Protein complexes that take part in the process of PHOTOSYNTHESIS. They are located within the THYLAKOID MEMBRANES of plant CHLOROPLASTS and a variety of structures in more primitive organisms. There are two major complexes involved in the photosynthetic process called PHOTOSYSTEM I and PHOTOSYSTEM II.
Spherical phototrophic bacteria found in mud and stagnant water exposed to light.
Complexes containing CHLOROPHYLL and other photosensitive molecules. They serve to capture energy in the form of PHOTONS and are generally found as components of the PHOTOSYSTEM I PROTEIN COMPLEX or the PHOTOSYSTEM II PROTEIN COMPLEX.
Pyrrole containing pigments found in photosynthetic bacteria.
A genus of gram-negative, rod-shaped, phototrophic bacteria found in aquatic environments. Internal photosynthetic membranes are present as lamellae underlying the cytoplasmic membrane.
A large multisubunit protein complex found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to catalyze the splitting of WATER into DIOXYGEN and of reducing equivalents of HYDROGEN.
The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)
Porphyrin derivatives containing magnesium that act to convert light energy in photosynthetic organisms.
Chlorophylls from which the magnesium has been removed by treatment with weak acid.
A large multisubunit protein complex that is found in the THYLAKOID MEMBRANE. It uses light energy derived from LIGHT-HARVESTING PROTEIN COMPLEXES to drive electron transfer reactions that result in either the reduction of NADP to NADPH or the transport of PROTONS across the membrane.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.
Type C cytochromes that are small (12-14 kD) single-heme proteins. They function as mobile electron carriers between membrane-bound enzymes in photosynthetic BACTERIA.
A phylum of anoxygenic, phototrophic bacteria including the family Chlorobiaceae. They occur in aquatic sediments, sulfur springs, and hot springs and utilize reduced sulfur compounds instead of oxygen.
Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.
A widely cultivated plant, native to Asia, having succulent, edible leaves eaten as a vegetable. (From American Heritage Dictionary, 1982)
A genus of gram-negative bacteria widely distributed in fresh water as well as marine and hypersaline habitats.
Proteins found in any species of bacterium.
A phylum of bacteria consisting of the purple bacteria and their relatives which form a branch of the eubacterial tree. This group of predominantly gram-negative bacteria is classified based on homology of equivalent nucleotide sequences of 16S ribosomal RNA or by hybridization of ribosomal RNA or DNA with 16S and 23S ribosomal RNA.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
A genus in the family ACETOBACTERACEAE consisting of chemoorganotrophic, straight rods with rounded ends. They are aerobic and acidophilic.
A family in the order Rhizobiales, class ALPHAPROTEOBACTERIA comprised of many genera of budding or appendaged bacteria.
Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.
Photochemistry is the study of chemical reactions induced by absorption of light, resulting in the promotion of electrons to higher energy levels and subsequent formation of radicals or excited molecules that can undergo various reaction pathways.
Organelles of phototrophic bacteria which contain photosynthetic pigments and which are formed from an invagination of the cytoplasmic membrane.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A genus of phototrophic, obligately anaerobic bacteria in the family Chlorobiaceae. They are found in hydrogen sulfide-containing mud and water environments.
A lipid-soluble benzoquinone which is involved in ELECTRON TRANSPORT in mitochondrial preparations. The compound occurs in the majority of aerobic organisms, from bacteria to higher plants and animals.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A genus of EUKARYOTES, in the phylum EUGLENIDA, found mostly in stagnant water. Characteristics include a pellicle usually marked by spiral or longitudinal striations.
The rate dynamics in chemical or physical systems.
Proteins, usually acting in oxidation-reduction reactions, containing iron but no porphyrin groups. (Lehninger, Principles of Biochemistry, 1993, pG-10)
A family of phototrophic bacteria, in the order Rhodospirillales, isolated from stagnant water and mud.
A pre-emergent herbicide.
The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A specific bacteriochlorophyll that is similar in structure to chlorophyll a.
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
A family of phototrophic purple sulfur bacteria that deposit globules of elemental sulfur inside their cells. They are found in diverse aquatic environments.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Non-pathogenic ovoid to rod-shaped bacteria that are widely distributed and found in fresh water as well as marine and hypersaline habitats.
A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)
A genus of facultatively or obligately anaerobic marine phototrophic bacteria, in the family RHODOBACTERACEAE.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
A genus of gram-negative, ovoid to rod-shaped bacteria that is phototrophic. All species use ammonia as a nitrogen source. Some strains are found only in sulfide-containing freshwater habitats exposed to light while others may occur in marine, estuarine, and freshwater environments.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.
Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.
The accumulation of an electric charge on a object
Benzene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
Proteins that form the structure of the NUCLEAR PORE. They are involved in active, facilitated and passive transport of molecules in and out of the CELL NUCLEUS.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.
The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Dimethylamines are organic compounds that contain two methyl groups (-CH3) bonded to a nitrogen atom (N), with the general formula (CH3)2NH. They can act as secondary amines and are commonly used in chemical synthesis, but they are not typically found as natural components in the human body.
Plant cell inclusion bodies that contain the photosynthetic pigment CHLOROPHYLL, which is associated with the membrane of THYLAKOIDS. Chloroplasts occur in cells of leaves and young stems of plants. They are also found in some forms of PHYTOPLANKTON such as HAPTOPHYTA; DINOFLAGELLATES; DIATOMS; and CRYPTOPHYTA.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
The functional hereditary units of BACTERIA.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

Role of a novel photosystem II-associated carbonic anhydrase in photosynthetic carbon assimilation in Chlamydomonas reinhardtii. (1/2359)

Intracellular carbonic anhydrases (CA) in aquatic photosynthetic organisms are involved in the CO2-concentrating mechanism (CCM), which helps to overcome CO2 limitation in the environment. In the green alga Chlamydomonas reinhardtii, this CCM is initiated and maintained by the pH gradient created across the chloroplast thylakoid membranes by photosystem (PS) II-mediated electron transport. We show here that photosynthesis is stimulated by a novel, intracellular alpha-CA bound to the chloroplast thylakoids. It is associated with PSII on the lumenal side of the thylakoid membranes. We demonstrate that PSII in association with this lumenal CA operates to provide an ample flux of CO2 for carboxylation.  (+info)

Two light-activated conductances in the eye of the green alga Volvox carteri. (2/2359)

Photoreceptor currents of the multicellular green alga Volvox carteri were analyzed using a dissolver mutant. The photocurrents are restricted to the eyespot region of somatic cells. Photocurrents are detectable from intact cells and excised eyes. The rhodopsin action spectrum suggests that the currents are induced by Volvox rhodopsin. Flash-induced photocurrents are a composition of a fast Ca2+-carried current (PF) and a slower current (PS), which is carried by H+. PF is a high-intensity response that appears with a delay of less than 50 micros after flash. The stimulus-response curve of its initial rise is fit by a single exponential and parallels the rhodopsin bleaching. These two observations suggest that the responsible channel is closely connected to the rhodopsin, both forming a tight complex. At low flash energies PS is dominating. The current delay increases up to 10 ms, and the PS amplitude saturates when only a few percent of the rhodopsin is bleached. The data are in favor of a second signaling system, which includes a signal transducer mediating between rhodopsin and the channel. We present a model of how different modes of signal transduction are accomplished in this alga under different light conditions.  (+info)

Multiple pathways for ultrafast transduction of light energy in the photosynthetic reaction center of Rhodobacter sphaeroides. (3/2359)

A pathway of electron transfer is described that operates in the wild-type reaction center (RC) of the photosynthetic bacterium Rhodobacter sphaeroides. The pathway does not involve the excited state of the special pair dimer of bacteriochlorophylls (P*), but instead is driven by the excited state of the monomeric bacteriochlorophyll (BA*) present in the active branch of pigments along which electron transfer occurs. Pump-probe experiments were performed at 77 K on membrane-bound RCs by using different excitation wavelengths, to investigate the formation of the charge separated state P+HA-. In experiments in which P or BA was selectively excited at 880 nm or 796 nm, respectively, the formation of P+HA- was associated with similar time constants of 1.5 ps and 1. 7 ps. However, the spectral changes associated with the two time constants are very different. Global analysis of the transient spectra shows that a mixture of P+BA- and P* is formed in parallel from BA* on a subpicosecond time scale. In contrast, excitation of the inactive branch monomeric bacteriochlorophyll (BB) and the high exciton component of P (P+) resulted in electron transfer only after relaxation to P*. The multiple pathways for primary electron transfer in the bacterial RC are discussed with regard to the mechanism of charge separation in the RC of photosystem II from higher plants.  (+info)

Lipophilicity determination of some potential photosystem II inhibitors on reversed-phase high-performance thin-layer chromatography. (4/2359)

The retention characteristics of 25 2-cyano-3-methylthio-3-substituted amine-acrylates are determined using reversed-phase thin-layer chromatography (RP-TLC) with methanol-water mixtures as eluents. The relationship between Rm values and partition coefficients (C log P) are established. The Rm values decrease linearly with increasing methanol concentration in the eluent. The Rm values extrapolated to zero organic modifier concentration (Rm0) in the eluent are highly related to C log P. The Rm0 value can be used to evaluate the lipophilicity of this kind of compound.  (+info)

A functional model for O-O bond formation by the O2-evolving complex in photosystem II. (5/2359)

The formation of molecular oxygen from water in photosynthesis is catalyzed by photosystem II at an active site containing four manganese ions that are arranged in di-mu-oxo dimanganese units (where mu is a bridging mode). The complex [H2O(terpy)Mn(O)2Mn(terpy)OH2](NO3)3 (terpy is 2,2':6', 2"-terpyridine), which was synthesized and structurally characterized, contains a di-mu-oxo manganese dimer and catalyzes the conversion of sodium hypochlorite to molecular oxygen. Oxygen-18 isotope labeling showed that water is the source of the oxygen atoms in the molecular oxygen evolved, and so this system is a functional model for photosynthetic water oxidation.  (+info)

Photosystem I, an improved model of the stromal subunits PsaC, PsaD, and PsaE. (6/2359)

An improved electron density map of photosystem I (PSI) calculated at 4-A resolution yields a more detailed structural model of the stromal subunits PsaC, PsaD, and PsaE than previously reported. The NMR structure of the subunit PsaE of PSI from Synechococcus sp. PCC7002 (Falzone, C. J., Kao, Y.-H., Zhao, J., Bryant, D. A., and Lecomte, J. T. J. (1994) Biochemistry 33, 6052-6062) has been used as a model to interpret the region of the electron density map corresponding to this subunit. The spatial orientation with respect to other subunits is described as well as the possible interactions between the stromal subunits. A first model of PsaD consisting of a four-stranded beta-sheet and an alpha-helix is suggested, indicating that this subunit partly shields PsaC from the stromal side. In addition to the improvements on the stromal subunits, the structural model of the membrane-integral region of PSI is also extended. The current electron density map allows the identification of the N and C termini of the subunits PsaA and PsaB. The 11-transmembrane alpha-helices of these subunits can now be assigned uniquely to the hydrophobic segments identified by hydrophobicity analyses.  (+info)

Localization of two phylloquinones, QK and QK', in an improved electron density map of photosystem I at 4-A resolution. (7/2359)

An improved electron density map of photosystem I from Synechococcus elongatus calculated at 4-A resolution for the first time reveals a second phylloquinone molecule and thereby completes the set of cofactors constituting the electron transfer system of this iron-sulfur type photosynthetic reaction center: six chlorophyll a, two phylloquinones, and three Fe4S4 clusters. The location of the newly identified phylloquinone pair, the individual plane orientations of these molecules, and the resulting distances to other cofactors of the electron transfer system are discussed and compared with those determined by magnetic resonance techniques.  (+info)

Structural features and assembly of the soluble overexpressed PsaD subunit of photosystem I. (8/2359)

PsaD is a peripheral protein on the reducing side of photosystem I (PS I). We expressed the psaD gene from the thermophilic cyanobacterium Mastigocladus laminosus in Escherichia coli and obtained a soluble protein with a polyhistidine tag at the carboxyl terminus. The soluble PsaD protein was purified by Ni-affinity chromatography and had a mass of 16716 Da by MALDI-TOF. The N-terminal amino acid sequence of the overexpressed PsaD matched the N-terminal sequence of the native PsaD from M. laminosus. The soluble PsaD could assemble into the PsaD-less PS I. As determined by isothermal titration calorimetry, PsaD bound to PS I with 1.0 binding site per PS I, the binding constant of 7.7x10(6) M-1, and the enthalpy change of -93.6 kJ mol-1. This is the first time that the binding constant and binding heat have been determined in the assembly of any photosynthetic membrane protein. To identify the surface-exposed domains, purified PS I complexes and overexpressed PsaD were treated with N-hydroxysuccinimidobiotin (NHS-biotin) and biotin-maleimide, and the biotinylated residues were mapped. The Cys66, Lys21, Arg118 and Arg119 residues were exposed on the surface of soluble PsaD whereas the Lys129 and Lys131 residues were not exposed on the surface. Consistent with the X-ray crystallographic studies on PS I, circular dichroism spectroscopy revealed that PsaD contains a small proportion of alpha-helical conformation.  (+info)

Photosynthetic Reaction Center (RC) Complex Proteins are specialized protein-pigment structures that play a crucial role in the primary process of light-driven electron transport during photosynthesis. They are present in the thylakoid membranes of cyanobacteria, algae, and higher plants.

The Photosynthetic Reaction Center Complex Proteins are composed of two major components: the light-harvesting complex (LHC) and the reaction center (RC). The LHC contains antenna pigments like chlorophylls and carotenoids that absorb sunlight and transfer the excitation energy to the RC. The RC is a multi-subunit protein complex containing cofactors such as bacteriochlorophyll, pheophytin, quinones, and iron-sulfur clusters.

When a photon of light is absorbed by the antenna pigments in the LHC, the energy is transferred to the RC, where it initiates a charge separation event. This results in the transfer of an electron from a donor molecule to an acceptor molecule, creating a flow of electrical charge and generating a transmembrane electrochemical gradient. The energy stored in this gradient is then used to synthesize ATP and reduce NADP+, which are essential for carbon fixation and other metabolic processes in the cell.

In summary, Photosynthetic Reaction Center Complex Proteins are specialized protein structures involved in capturing light energy and converting it into chemical energy during photosynthesis, ultimately driving the synthesis of ATP and NADPH for use in carbon fixation and other metabolic processes.

Rhodobacter sphaeroides is not a medical term, but rather a scientific name for a type of bacteria. It belongs to the class of proteobacteria and is commonly found in soil, fresh water, and the ocean. This bacterium is capable of photosynthesis, and it can use light as an energy source, converting it into chemical energy. Rhodobacter sphaeroides is often studied in research settings due to its unique metabolic capabilities and potential applications in biotechnology.

In a medical context, Rhodobacter sphaeroides may be mentioned in relation to rare cases of infection, particularly in individuals with weakened immune systems. However, it is not considered a significant human pathogen, and there are no specific medical definitions associated with this bacterium.

Light-harvesting protein complexes are specialized structures in photosynthetic organisms, such as plants, algae, and some bacteria, that capture and transfer light energy to the reaction centers where the initial chemical reactions of photosynthesis occur. These complexes consist of proteins and pigments (primarily chlorophylls and carotenoids) arranged in a way that allows them to absorb light most efficiently. The absorbed light energy is then converted into electrical charges, which are transferred to the reaction centers for further chemical reactions leading to the production of organic compounds and oxygen. The light-harvesting protein complexes play a crucial role in initiating the process of photosynthesis and optimizing its efficiency by capturing and distributing light energy.

Bacteriochlorophylls are a type of pigment that are found in certain bacteria and are used in photosynthesis. They are similar to chlorophylls, which are found in plants and algae, but have some differences in their structure and absorption spectrum. Bacteriochlorophylls absorb light at longer wavelengths than chlorophylls, with absorption peaks in the near-infrared region of the electromagnetic spectrum. This allows bacteria that contain bacteriochlorophylls to carry out photosynthesis in environments with low levels of light or at great depths in the ocean where sunlight is scarce.

There are several different types of bacteriochlorophylls, including bacteriochlorophyll a, bacteriochlorophyll b, and bacteriochlorophyll c. These pigments play a role in the capture of light energy during photosynthesis and are involved in the electron transfer processes that occur during this process. Bacteriochlorophylls are also used as a taxonomic marker to help classify certain groups of bacteria.

Rhodopseudomonas is a genus of gram-negative, rod-shaped bacteria that are capable of photosynthesis. These bacteria contain bacteriochlorophyll and can use light as an energy source in the absence of oxygen, which makes them facultative anaerobes. They typically inhabit freshwater and soil environments, and some species are able to fix nitrogen gas. Rhodopseudomonas species are known to cause various infections in humans, including bacteremia, endocarditis, and respiratory tract infections, particularly in immunocompromised individuals. However, such infections are relatively rare.

Photosystem II Protein Complex is a crucial component of the photosynthetic apparatus in plants, algae, and cyanobacteria. It is a multi-subunit protein complex located in the thylakoid membrane of the chloroplasts. Photosystem II plays a vital role in light-dependent reactions of photosynthesis, where it absorbs sunlight and uses its energy to drive the oxidation of water molecules into oxygen, electrons, and protons.

The protein complex consists of several subunits, including the D1 and D2 proteins, which form the reaction center, and several antenna proteins that capture light energy and transfer it to the reaction center. Photosystem II also contains various cofactors, such as pigments (chlorophylls and carotenoids), redox-active metal ions (manganese and calcium), and quinones, which facilitate the charge separation and electron transfer processes during photosynthesis.

Photosystem II Protein Complex is responsible for the initial charge separation event in photosynthesis, which sets off a series of redox reactions that ultimately lead to the reduction of NADP+ to NADPH and the synthesis of ATP, providing energy for the carbon fixation reactions in the Calvin cycle. Additionally, Photosystem II Protein Complex is involved in oxygen evolution, contributing to the Earth's atmosphere's oxygen levels and making it an essential component of global carbon fixation and oxygen production.

The Electron Transport Chain (ETC) is a series of complexes in the inner mitochondrial membrane that are involved in the process of cellular respiration. It is the final pathway for electrons derived from the oxidation of nutrients such as glucose, fatty acids, and amino acids to be transferred to molecular oxygen. This transfer of electrons drives the generation of a proton gradient across the inner mitochondrial membrane, which is then used by ATP synthase to produce ATP, the main energy currency of the cell.

The electron transport chain consists of four complexes (I-IV) and two mobile electron carriers (ubiquinone and cytochrome c). Electrons from NADH and FADH2 are transferred to Complex I and Complex II respectively, which then pass them along to ubiquinone. Ubiquinone then transfers the electrons to Complex III, which passes them on to cytochrome c. Finally, cytochrome c transfers the electrons to Complex IV, where they combine with oxygen and protons to form water.

The transfer of electrons through the ETC is accompanied by the pumping of protons from the mitochondrial matrix to the intermembrane space, creating a proton gradient. The flow of protons back across the inner membrane through ATP synthase drives the synthesis of ATP from ADP and inorganic phosphate.

Overall, the electron transport chain is a crucial process for generating energy in the form of ATP in the cell, and it plays a key role in many metabolic pathways.

Photosynthesis is not strictly a medical term, but it is a fundamental biological process with significant implications for medicine, particularly in understanding energy production in cells and the role of oxygen in sustaining life. Here's a general biological definition:

Photosynthesis is a process by which plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy in the form of organic compounds, such as glucose (or sugar), using water and carbon dioxide. This process primarily takes place in the chloroplasts of plant cells, specifically in structures called thylakoids. The overall reaction can be summarized as:

6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2

In this equation, carbon dioxide (CO2) and water (H2O) are the reactants, while glucose (C6H12O6) and oxygen (O2) are the products. Photosynthesis has two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). The light-dependent reactions occur in the thylakoid membrane and involve the conversion of light energy into ATP and NADPH, which are used to power the Calvin cycle. The Calvin cycle takes place in the stroma of chloroplasts and involves the synthesis of glucose from CO2 and water using the ATP and NADPH generated during the light-dependent reactions.

Understanding photosynthesis is crucial for understanding various biological processes, including cellular respiration, plant metabolism, and the global carbon cycle. Additionally, research into artificial photosynthesis has potential applications in renewable energy production and environmental remediation.

Chlorophyll is a green pigment found in the chloroplasts of photosynthetic plants, algae, and some bacteria. It plays an essential role in light-dependent reactions of photosynthesis by absorbing light energy, primarily from the blue and red parts of the electromagnetic spectrum, and converting it into chemical energy to fuel the synthesis of carbohydrates from carbon dioxide and water. The structure of chlorophyll includes a porphyrin ring, which binds a central magnesium ion, and a long phytol tail. There are several types of chlorophyll, including chlorophyll a and chlorophyll b, which have distinct absorption spectra and slightly different structures. Chlorophyll is crucial for the process of photosynthesis, enabling the conversion of sunlight into chemical energy and the release of oxygen as a byproduct.

Pheophytins are pigments that are formed when the magnesium ion is lost from chlorophylls, which are the green pigments involved in photosynthesis. This results in the conversion of chlorophyll a and chlorophyll b to pheophytin a and pheophytin b, respectively. Pheophytins do not participate in light absorption during photosynthesis and have a different spectral absorption pattern compared to chlorophylls. They are believed to play a role in the photoprotection of photosystem II by dissipating excess energy absorbed by the antenna complexes as heat, thereby preventing the formation of harmful reactive oxygen species.

Photosystem I Protein Complex, also known as PsaA/B-Protein or Photosystem I reaction center, is a large protein complex found in the thylakoid membrane of plant chloroplasts and cyanobacteria. It plays a crucial role in light-dependent reactions of photosynthesis, where it absorbs light energy and converts it into chemical energy in the form of NADPH.

The complex is composed of several subunits, including PsaA and PsaB, which are the core components that bind to chlorophyll a and bacteriochlorophyll a pigments. These pigments absorb light energy and transfer it to the reaction center, where it is used to drive the electron transport chain and generate a proton gradient across the membrane. This gradient is then used to produce ATP, which provides energy for the carbon fixation reactions in photosynthesis.

Photosystem I Protein Complex is also involved in cyclic electron flow, where electrons are recycled within the complex to generate additional ATP without producing NADPH. This process helps regulate the balance between ATP and NADPH production in the chloroplast and optimizes the efficiency of photosynthesis.

In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:

1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.

Without more context, it's hard to provide a precise medical definition of 'light'.

Cyanobacteria, also known as blue-green algae, are a type of bacteria that obtain their energy through photosynthesis, similar to plants. They can produce oxygen and contain chlorophyll a, which gives them a greenish color. Some species of cyanobacteria can produce toxins that can be harmful to humans and animals if ingested or inhaled. They are found in various aquatic environments such as freshwater lakes, ponds, and oceans, as well as in damp soil and on rocks. Cyanobacteria are important contributors to the Earth's oxygen-rich atmosphere and play a significant role in the global carbon cycle.

Cytochrome c2 is a type of cytochrome, which is a small water-soluble protein involved in electron transport chains and associated with the inner membrane of mitochondria. Cytochrome c2 specifically contains heme as a cofactor and plays a role in the respiratory chain of certain bacteria, contributing to their energy production through oxidative phosphorylation. It is not found in human or mammalian cells.

Chlorobi, also known as green sulfur bacteria, are a group of anaerobic, phototrophic bacteria that contain chlorophylls a and b, as well as bacteriochlorophyll c, d, or e. They obtain energy through photosynthesis, using light as an energy source and sulfide or other reduced sulfur compounds as electron donors. These bacteria are typically found in environments with limited sunlight and high sulfide concentrations, such as in sediments of stratified water bodies or in microbial mats. They play a significant role in the global carbon and sulfur cycles.

Quinones are a class of organic compounds that contain a fully conjugated diketone structure. This structure consists of two carbonyl groups (C=O) separated by a double bond (C=C). Quinones can be found in various biological systems and synthetic compounds. They play important roles in many biochemical processes, such as electron transport chains and redox reactions. Some quinones are also known for their antimicrobial and anticancer properties. However, some quinones can be toxic or mutagenic at high concentrations.

Spectrophotometry is a technical analytical method used in the field of medicine and science to measure the amount of light absorbed or transmitted by a substance at specific wavelengths. This technique involves the use of a spectrophotometer, an instrument that measures the intensity of light as it passes through a sample.

In medical applications, spectrophotometry is often used in laboratory settings to analyze various biological samples such as blood, urine, and tissues. For example, it can be used to measure the concentration of specific chemicals or compounds in a sample by measuring the amount of light that is absorbed or transmitted at specific wavelengths.

In addition, spectrophotometry can also be used to assess the properties of biological tissues, such as their optical density and thickness. This information can be useful in the diagnosis and treatment of various medical conditions, including skin disorders, eye diseases, and cancer.

Overall, spectrophotometry is a valuable tool for medical professionals and researchers seeking to understand the composition and properties of various biological samples and tissues.

"Energy transfer" is a general term used in the field of physics and physiology, including medical sciences, to describe the process by which energy is passed from one system, entity, or location to another. In the context of medicine, energy transfer often refers to the ways in which cells and organ systems exchange and utilize various forms of energy for proper functioning and maintenance of life.

In a more specific sense, "energy transfer" may refer to:

1. Bioenergetics: This is the study of energy flow through living organisms, including the conversion, storage, and utilization of energy in biological systems. Key processes include cellular respiration, photosynthesis, and metabolic pathways that transform energy into forms useful for growth, maintenance, and reproduction.
2. Electron transfer: In biochemistry, electrons are transferred between molecules during redox reactions, which play a crucial role in energy production and consumption within cells. Examples include the electron transport chain (ETC) in mitochondria, where high-energy electrons from NADH and FADH2 are passed along a series of protein complexes to generate an electrochemical gradient that drives ATP synthesis.
3. Heat transfer: This is the exchange of thermal energy between systems or objects due to temperature differences. In medicine, heat transfer can be relevant in understanding how body temperature is regulated and maintained, as well as in therapeutic interventions such as hyperthermia or cryotherapy.
4. Mechanical energy transfer: This refers to the transmission of mechanical force or motion from one part of the body to another. For instance, muscle contractions generate forces that are transmitted through tendons and bones to produce movement and maintain posture.
5. Radiation therapy: In oncology, ionizing radiation is used to treat cancer by transferring energy to malignant cells, causing damage to their DNA and leading to cell death or impaired function.
6. Magnetic resonance imaging (MRI): This non-invasive diagnostic technique uses magnetic fields and radio waves to excite hydrogen nuclei in the body, which then release energy as they return to their ground state. The resulting signals are used to generate detailed images of internal structures and tissues.

In summary, "energy transfer" is a broad term that encompasses various processes by which different forms of energy (thermal, mechanical, electromagnetic, etc.) are exchanged or transmitted between systems or objects in the context of medicine and healthcare.

"Spinacia oleracea" is the scientific name for a plant species, not a medical term. It is commonly known as spinach, a leafy green vegetable. While spinach has many health benefits and is often recommended as part of a balanced diet, it does not have a specific medical definition.

Spinach is rich in various nutrients such as iron, calcium, vitamin A, vitamin C, and folic acid. It can contribute to overall health, support immune function, and provide antioxidant benefits. However, it is important to note that 'Spinacia oleracea' itself does not have a medical definition.

Rhodobacter is not a medical term, but a genus of bacteria found in the environment. It is commonly found in aquatic environments and can perform photosynthesis, although it is not classified as a plant. Some species of Rhodobacter are capable of fixing nitrogen gas from the atmosphere, making them important contributors to the global nitrogen cycle.

While there may be some medical research into the potential uses or impacts of certain species of Rhodobacter, there is no widely recognized medical definition for this term. If you have any specific concerns about bacteria or infections, it's best to consult with a healthcare professional for accurate information and advice.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

Proteobacteria is a major class of Gram-negative bacteria that includes a wide variety of pathogens and free-living organisms. This class is divided into six subclasses: Alpha, Beta, Gamma, Delta, Epsilon, and Zeta proteobacteria. Proteobacteria are characterized by their single circular chromosome and the presence of lipopolysaccharide (LPS) in their outer membrane. They can be found in a wide range of environments, including soil, water, and the gastrointestinal tracts of animals. Some notable examples of Proteobacteria include Escherichia coli, Salmonella enterica, and Yersinia pestis.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

'Acidiphilium' is a genus of bacteria that are characterized by their ability to thrive in highly acidic environments, typically with a pH between 1 and 5. These bacteria are gram-negative, motile, and rod-shaped, and they are commonly found in natural environments such as acid mine drainage, soil, and water. They are able to use a variety of organic compounds as their energy source and are often involved in the biogeochemical cycling of elements such as carbon, nitrogen, and sulfur. Some species of 'Acidiphilium' have been studied for their potential applications in bioremediation and other industrial processes.

Hyphomicrobiaceae is a family of bacteria that are characterized by their unique mode of reproduction known as "budding." This type of reproduction involves the formation of a new cell, or bud, on the surface of the parent cell. Once the bud has reached a certain size, it will separate from the parent cell and become a fully functioning independent organism.

Members of Hyphomicrobiaceae are typically gram-negative, aerobic bacteria that are found in a variety of environments, including soil, water, and plant material. They are often associated with nitrogen fixation, a process by which certain bacteria are able to convert atmospheric nitrogen into ammonia, a form that can be used by plants for growth.

One notable genus within Hyphomicrobiaceae is Hyphomicrobium, which is known for its ability to oxidize methanol and other single-carbon compounds as a source of energy. This makes it an important player in the global carbon cycle, as it helps to convert methane, a potent greenhouse gas, into less harmful forms.

Overall, Hyphomicrobiaceae is an interesting family of bacteria with diverse metabolic capabilities and ecological roles.

An electron is a subatomic particle, symbol e-, with a negative electric charge. Electrons are fundamental components of atoms and are responsible for the chemical bonding between atoms to form molecules. They are located in an atom's electron cloud, which is the outermost region of an atom and contains negatively charged electrons that surround the positively charged nucleus.

Electrons have a mass that is much smaller than that of protons or neutrons, making them virtually weightless on the atomic scale. They are also known to exhibit both particle-like and wave-like properties, which is a fundamental concept in quantum mechanics. Electrons play a crucial role in various physical phenomena, such as electricity, magnetism, and chemical reactions.

I'm sorry for any confusion, but "photochemistry" is not a term typically used in medical definitions. Photochemistry is a branch of chemistry that deals with the chemical effects of light. It involves the absorption of light by a substance, which can lead to the promotion of an electron to a higher energy state, and subsequently result in various chemical reactions.

In a medical context, photochemical processes might be discussed in relation to certain therapies or diagnostic techniques, such as photodynamic therapy for cancer treatment, where a photosensitizing agent is used that reacts with light to produce singlet oxygen or other reactive species to destroy nearby cells. However, it's not a term used to define a specific medical condition or concept in the same way that one might define "inflammation" or "metabolism."

Bacterial chromatophores are membranous structures within certain bacteria that contain pigments and are involved in light absorption. They are primarily found in photosynthetic bacteria, where they play a crucial role in the process of photosynthesis by capturing light energy and converting it into chemical energy.

The term "chromatophore" is derived from the Greek words "chroma," meaning color, and "phoros," meaning bearer. In bacteria, chromatophores are typically composed of one or more membrane-bound vesicles called thylakoids, which contain various pigments such as bacteriochlorophylls and carotenoids.

Bacterial chromatophores can be found in several groups of photosynthetic bacteria, including cyanobacteria, green sulfur bacteria, purple sulfur bacteria, and purple nonsulfur bacteria. The specific arrangement and composition of the pigments within the chromatophores determine the type of light that is absorbed and the wavelengths that are utilized for photosynthesis.

Overall, bacterial chromatophores are essential organelles for the survival and growth of many photosynthetic bacteria, allowing them to harness the energy from sunlight to fuel their metabolic processes.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Chlorobium is a genus of photosynthetic bacteria that are primarily found in anaerobic environments, such as freshwater and marine sediments, and in the upper layers of microbial mats. These bacteria contain bacteriochlorophylls and use light energy to convert carbon dioxide into organic compounds through a process called chemosynthesis. Chlorobium species are important contributors to the global carbon cycle and play a significant role in the ecology of anaerobic environments.

The medical relevance of Chlorobium is limited, as these bacteria do not typically interact with humans or animals in a way that causes disease. However, they may be of interest to researchers studying photosynthesis, carbon cycling, and microbial ecology.

Ubiquinone, also known as coenzyme Q10 (CoQ10), is a lipid-soluble benzoquinone that plays a crucial role in the mitochondrial electron transport chain as an essential component of Complexes I, II, and III. It functions as an electron carrier, assisting in the transfer of electrons from reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH2) to molecular oxygen during oxidative phosphorylation, thereby contributing to the generation of adenosine triphosphate (ATP), the primary energy currency of the cell.

Additionally, ubiquinone acts as a potent antioxidant in both membranes and lipoproteins, protecting against lipid peroxidation and oxidative damage to proteins and DNA. Its antioxidant properties stem from its ability to donate electrons and regenerate other antioxidants like vitamin E. Ubiquinone is synthesized endogenously in all human cells, with the highest concentrations found in tissues with high energy demands, such as the heart, liver, kidneys, and skeletal muscles.

Deficiency in ubiquinone can result from genetic disorders, aging, or certain medications (such as statins), leading to impaired mitochondrial function and increased oxidative stress. Supplementation with ubiquinone has been explored as a potential therapeutic strategy for various conditions associated with mitochondrial dysfunction and oxidative stress, including cardiovascular diseases, neurodegenerative disorders, and cancer.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

'Euglena' is a genus of unicellular flagellate protists that are typically characterized by their oval-shaped bodies, long whip-like tail (flagellum), and eyespot (stigma) which helps them to move towards light. They are commonly found in freshwater environments and can also be found in soil and brackish water. Some species of Euglena have the ability to photosynthesize, while others obtain their nutrition through heterotrophy (consuming other organisms or organic matter). The term 'Euglena' is derived from the Greek word 'euglenes', which means "well-shaped" or "true-eyed". Medical professionals and researchers may study Euglena as part of broader research into protists, microbiology, or ecology.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Non-heme iron proteins are a type of iron-containing protein that do not contain heme as their prosthetic group. Heme is a complex molecule consisting of an iron atom contained in the center of a porphyrin ring, which is a large organic molecule made up of four pyrrole rings joined together. In contrast, non-heme iron proteins contain iron that is bound to the protein in other ways, such as through coordination with amino acid side chains or through association with an iron-sulfur cluster.

Examples of non-heme iron proteins include ferritin and transferrin, which are involved in the storage and transport of iron in the body, respectively. Ferritin is a protein that stores iron in a form that is safe and bioavailable for use by the body. Transferrin, on the other hand, binds to iron in the intestines and transports it to cells throughout the body.

Non-heme iron proteins are important for many biological processes, including oxygen transport, electron transfer, and enzyme catalysis. They play a crucial role in energy metabolism, DNA synthesis, and other essential functions.

Rhodospirillaceae is a family of purple bacteria within the class Alphaproteobacteria. These bacteria are characterized by their ability to perform anoxygenic photosynthesis, using bacteriochlorophyll and other pigments to capture light energy for use in metabolism. They typically contain one or more polar flagella and have a spiral or curved cell shape. Members of this family can be found in various environments such as freshwater, marine habitats, and soil, where they play important roles in carbon and nitrogen cycling. Some species are capable of fixing atmospheric nitrogen, making them significant contributors to the global nitrogen cycle.

Diuron is a pesticide and herbicide that is used to control weeds in various settings, such as agriculture, landscaping, and forestry. Its chemical name is 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Diuron works by inhibiting photosynthesis in plants, which prevents them from growing and eventually kills them.

While diuron is effective at controlling weeds, it can also have harmful effects on non-target organisms, including aquatic life and pollinators. Additionally, there are concerns about the potential for diuron to contaminate water sources and pose risks to human health. As a result, its use is regulated in many countries, and there are restrictions on how it can be applied and disposed of.

It's worth noting that Diuron is not a medical term or a drug used for treating any medical condition in humans or animals.

I'm sorry for any confusion, but "spectrum analysis" is not a commonly used medical term. Spectrum analysis is a term that is more frequently used in the fields of physics, mathematics, and engineering to describe the process of breaking down a signal or a wave into its different frequencies and amplitudes, creating a visual representation called a spectrum.

If you have any concerns about a medical issue, I would recommend consulting with a healthcare professional for accurate information and guidance.

Bacteriochlorophyll A is a type of pigment-protein complex found in certain photosynthetic bacteria. It plays a crucial role in the process of anaerobic photosynthesis, where it absorbs light energy and converts it into chemical energy through a series of reactions.

The structure of bacteriochlorophyll A is similar to that of chlorophylls found in plants and cyanobacteria, but with some key differences. One major difference is the type of light that it absorbs. While chlorophylls absorb light primarily in the blue and red regions of the electromagnetic spectrum, bacteriochlorophyll A absorbs light in the near-infrared region, between 700 and 1000 nanometers.

Bacteriochlorophyll A is an essential component of the photosynthetic apparatus in purple bacteria and green sulfur bacteria, which are two groups of photosynthetic bacteria that live in environments with low light levels. These bacteria use bacteriochlorophyll A to capture light energy and power the synthesis of ATP and NADPH, which are used to fuel the production of organic compounds from carbon dioxide.

In summary, bacteriochlorophyll A is a type of pigment-protein complex found in certain photosynthetic bacteria that plays a crucial role in anaerobic photosynthesis by absorbing light energy and converting it into chemical energy through a series of reactions.

In the context of medicine, particularly in relation to cancer treatment, protons refer to positively charged subatomic particles found in the nucleus of an atom. Proton therapy, a type of radiation therapy, uses a beam of protons to target and destroy cancer cells with high precision, minimizing damage to surrounding healthy tissue. The concentrated dose of radiation is delivered directly to the tumor site, reducing side effects and improving quality of life during treatment.

Chromatiaceae is a family of bacteria that are primarily characterized by their ability to photosynthesize and store energy in the form of sulfur granules. These bacteria are often found in aquatic environments, such as in salt marshes, freshwater sediments, and marine ecosystems. They are capable of using reduced sulfur compounds as an electron donor during photosynthesis, which distinguishes them from other photosynthetic bacteria that use water as an electron donor.

Chromatiaceae bacteria are gram-negative rods or curved rods, and they typically form distinct layers in the environment where they live. They are often found in stratified water columns, where they can form a layer of purple or brown-colored cells that are visible to the naked eye. The pigmentation comes from bacteriochlorophylls and carotenoids, which are used in light absorption during photosynthesis.

These bacteria play an important role in the biogeochemical cycling of sulfur and carbon in aquatic environments. They can help to remove excess nutrients from the water column, and they can also serve as a food source for other organisms in the ecosystem. However, some species of Chromatiaceae can also be associated with harmful algal blooms or other environmental disturbances that can have negative impacts on water quality and aquatic life.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

Rhodobacter capsulatus is not a medical term, but a species name in the field of microbiology. It refers to a type of purple nonsulfur bacteria that is capable of photosynthesis and can be found in freshwater and soil environments. These bacteria are known for their ability to switch between using light and organic compounds as sources of energy, depending on the availability of each. They have been studied for their potential applications in biotechnology and renewable energy production.

While not directly related to medical definitions, some research has explored the potential use of Rhodobacter capsulatus in bioremediation and wastewater treatment due to its ability to break down various organic compounds. However, it is not a pathogenic organism and does not have any direct relevance to human health or disease.

Cytochrome c is a small protein that is involved in the electron transport chain, a key part of cellular respiration in which cells generate energy in the form of ATP. Cytochrome c contains a heme group, which binds to and transports electrons. The cytochrome c group refers to a class of related cytochromes that have similar structures and functions. These proteins are found in the mitochondria of eukaryotic cells (such as those of plants and animals) and in the inner membranes of bacteria. They play a crucial role in the production of energy within the cell, and are also involved in certain types of programmed cell death (apoptosis).

I apologize for any confusion, but "Rhodovulum" is not a medical term, but rather a taxonomic genus name in the field of microbiology. It belongs to the family of purple sulfur bacteria, Rhodospirillaceae, and includes several species of photosynthetic, gram-negative bacteria that are commonly found in aquatic environments. These bacteria are capable of using light as an energy source and sulfur compounds as electron donors during photosynthesis. They play a role in the biogeochemical cycling of elements such as carbon, sulfur, and nitrogen in various ecosystems.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

Electrochemistry is a branch of chemistry that deals with the interconversion of electrical energy and chemical energy. It involves the study of chemical processes that cause electrons to move, resulting in the transfer of electrical charge, and the reverse processes by which electrical energy can be used to drive chemical reactions. This field encompasses various phenomena such as the generation of electricity from chemical sources (as in batteries), the electrolysis of substances, and corrosion. Electrochemical reactions are fundamental to many technologies, including energy storage and conversion, environmental protection, and medical diagnostics.

"Chromatium" is a genus of bacteria that are commonly found in aquatic environments, particularly in anaerobic or low-oxygen conditions. These bacteria are known for their ability to perform anaerobic respiration using sulfur as the final electron acceptor in the electron transport chain. This process is often referred to as "sulfur reduction" or "sulfur respiration."

The name "Chromatium" comes from the Greek word "chroma," which means "color," and refers to the distinctive purple color of these bacteria, which is due to the presence of bacteriochlorophyll and carotenoid pigments. These pigments allow Chromatium species to perform photosynthesis, using light energy to convert carbon dioxide into organic compounds.

It's worth noting that "Chromatium" is a specific taxonomic name for a genus of bacteria, and should not be confused with the more general term "chromatin," which refers to the complex of DNA, histone proteins, and other molecules that make up the chromosomes in eukaryotic cells.

I'm sorry for any confusion, but "thermodynamics" is not a term that has a specific medical definition. It is a branch of physics that deals with the relationships between heat and other forms of energy. However, the principles of thermodynamics can be applied to biological systems, including those in the human body, such as in the study of metabolism or muscle function. But in a medical context, "thermodynamics" would not be a term used independently as a diagnosis, treatment, or any medical condition.

Electron Spin Resonance (ESR) Spectroscopy, also known as Electron Paramagnetic Resonance (EPR) Spectroscopy, is a technique used to investigate materials with unpaired electrons. It is based on the principle of absorption of energy by the unpaired electrons when they are exposed to an external magnetic field and microwave radiation.

In this technique, a sample is placed in a magnetic field and microwave radiation is applied. The unpaired electrons in the sample absorb energy and change their spin state when the energy of the microwaves matches the energy difference between the spin states. This absorption of energy is recorded as a function of the magnetic field strength, producing an ESR spectrum.

ESR spectroscopy can provide information about the number, type, and behavior of unpaired electrons in a sample, as well as the local environment around the electron. It is widely used in physics, chemistry, and biology to study materials such as free radicals, transition metal ions, and defects in solids.

Electrophoresis, polyacrylamide gel (EPG) is a laboratory technique used to separate and analyze complex mixtures of proteins or nucleic acids (DNA or RNA) based on their size and electrical charge. This technique utilizes a matrix made of cross-linked polyacrylamide, a type of gel, which provides a stable and uniform environment for the separation of molecules.

In this process:

1. The polyacrylamide gel is prepared by mixing acrylamide monomers with a cross-linking agent (bis-acrylamide) and a catalyst (ammonium persulfate) in the presence of a buffer solution.
2. The gel is then poured into a mold and allowed to polymerize, forming a solid matrix with uniform pore sizes that depend on the concentration of acrylamide used. Higher concentrations result in smaller pores, providing better resolution for separating smaller molecules.
3. Once the gel has set, it is placed in an electrophoresis apparatus containing a buffer solution. Samples containing the mixture of proteins or nucleic acids are loaded into wells on the top of the gel.
4. An electric field is applied across the gel, causing the negatively charged molecules to migrate towards the positive electrode (anode) while positively charged molecules move toward the negative electrode (cathode). The rate of migration depends on the size, charge, and shape of the molecules.
5. Smaller molecules move faster through the gel matrix and will migrate farther from the origin compared to larger molecules, resulting in separation based on size. Proteins and nucleic acids can be selectively stained after electrophoresis to visualize the separated bands.

EPG is widely used in various research fields, including molecular biology, genetics, proteomics, and forensic science, for applications such as protein characterization, DNA fragment analysis, cloning, mutation detection, and quality control of nucleic acid or protein samples.

A chemical model is a simplified representation or description of a chemical system, based on the laws of chemistry and physics. It is used to explain and predict the behavior of chemicals and chemical reactions. Chemical models can take many forms, including mathematical equations, diagrams, and computer simulations. They are often used in research, education, and industry to understand complex chemical processes and develop new products and technologies.

For example, a chemical model might be used to describe the way that atoms and molecules interact in a particular reaction, or to predict the properties of a new material. Chemical models can also be used to study the behavior of chemicals at the molecular level, such as how they bind to each other or how they are affected by changes in temperature or pressure.

It is important to note that chemical models are simplifications of reality and may not always accurately represent every aspect of a chemical system. They should be used with caution and validated against experimental data whenever possible.

Iron-sulfur proteins are a group of metalloproteins that contain iron and sulfur atoms in their active centers. These clusters of iron and sulfur atoms, also known as iron-sulfur clusters, can exist in various forms, including Fe-S, 2Fe-2S, 3Fe-4S, and 4Fe-4S structures. The iron atoms are coordinated to the protein through cysteine residues, while the sulfur atoms can be in the form of sulfide (S2-) or sulfane (-S-).

These proteins play crucial roles in many biological processes, such as electron transfer, redox reactions, and enzyme catalysis. They are found in various organisms, from bacteria to humans, and are involved in a wide range of cellular functions, including energy metabolism, photosynthesis, nitrogen fixation, and DNA repair.

Iron-sulfur proteins can be classified into several categories based on their structure and function, such as ferredoxins, Rieske proteins, high-potential iron-sulfur proteins (HiPIPs), and radical SAM enzymes. Dysregulation or mutations in iron-sulfur protein genes have been linked to various human diseases, including neurodegenerative disorders, cancer, and mitochondrial disorders.

Cytochromes are a type of hemeprotein found in the mitochondria and other cellular membranes of organisms. They contain a heme group, which is a prosthetic group composed of an iron atom surrounded by a porphyrin ring. This structure allows cytochromes to participate in redox reactions, acting as electron carriers in various biological processes.

There are several types of cytochromes, classified based on the type of heme they contain and their absorption spectra. Some of the most well-known cytochromes include:

* Cytochrome c: a small, mobile protein found in the inner mitochondrial membrane that plays a crucial role in the electron transport chain during cellular respiration.
* Cytochrome P450: a large family of enzymes involved in the metabolism of drugs, toxins, and other xenobiotics. They are found in various tissues, including the liver, lungs, and skin.
* Cytochrome b: a component of several electron transport chains, including those found in mitochondria, bacteria, and chloroplasts.

Cytochromes play essential roles in energy production, detoxification, and other metabolic processes, making them vital for the survival and function of living organisms.

I'm sorry for any confusion, but static electricity is not a term that has a specific medical definition. Static electricity is an electrical charge that builds up on the surface of objects. This occurs when there is an imbalance of electric charges within or on the surface of a material. It can be caused by certain conditions, such as friction, which can build up an electric charge.

While not a medical term, static electricity can have various effects in different settings, including medical ones. For instance, it can cause issues with electronic equipment used in healthcare settings. Additionally, some people may experience a shock or spark when they touch a conductive object that has been charged with static electricity. However, these occurrences are not typically considered medical conditions or issues.

Benzoquinones are a type of chemical compound that contain a benzene ring (a cyclic arrangement of six carbon atoms) with two ketone functional groups (-C=O) in the 1,4-positions. They exist in two stable forms, namely ortho-benzoquinone and para-benzoquinone, depending on the orientation of the ketone groups relative to each other.

Benzoquinones are important intermediates in various biological processes and are also used in industrial applications such as dyes, pigments, and pharmaceuticals. They can be produced synthetically or obtained naturally from certain plants and microorganisms.

In the medical field, benzoquinones have been studied for their potential therapeutic effects, particularly in the treatment of cancer and infectious diseases. However, they are also known to exhibit toxicity and may cause adverse reactions in some individuals. Therefore, further research is needed to fully understand their mechanisms of action and potential risks before they can be safely used as drugs or therapies.

Nuclear pore complex proteins, also known as nucleoporins, are a group of specialized proteins that make up the nuclear pore complex (NPC), a large protein structure found in the nuclear envelope of eukaryotic cells. The NPC regulates the transport of molecules between the nucleus and the cytoplasm.

Nucleoporins are organized into distinct subcomplexes, which together form the NPC. They contain phenylalanine-glycine (FG) repeats, which are stretches of amino acids rich in phenylalanine and glycine residues. These FG repeats interact with transport factors, which are responsible for carrying molecules through the NPC.

Nucleoporins play a critical role in the regulation of nuclear transport, and mutations in these proteins have been linked to various human diseases, including neurological disorders and cancer.

X-ray crystallography is a technique used in structural biology to determine the three-dimensional arrangement of atoms in a crystal lattice. In this method, a beam of X-rays is directed at a crystal and diffracts, or spreads out, into a pattern of spots called reflections. The intensity and angle of each reflection are measured and used to create an electron density map, which reveals the position and type of atoms in the crystal. This information can be used to determine the molecular structure of a compound, including its shape, size, and chemical bonds. X-ray crystallography is a powerful tool for understanding the structure and function of biological macromolecules such as proteins and nucleic acids.

Hydrogen bonding is not a medical term per se, but it is a fundamental concept in chemistry and biology that is relevant to the field of medicine. Here's a general definition:

Hydrogen bonding is a type of attractive force between molecules or within a molecule, which occurs when a hydrogen atom is bonded to a highly electronegative atom (like nitrogen, oxygen, or fluorine) and is then attracted to another electronegative atom. This attraction results in the formation of a partially covalent bond known as a "hydrogen bond."

In biological systems, hydrogen bonding plays a crucial role in the structure and function of many biomolecules, such as DNA, proteins, and carbohydrates. For example, the double helix structure of DNA is stabilized by hydrogen bonds between complementary base pairs (adenine-thymine and guanine-cytosine). Similarly, the three-dimensional structure of proteins is maintained by a network of hydrogen bonds that help to determine their function.

In medical contexts, hydrogen bonding can be relevant in understanding drug-receptor interactions, where hydrogen bonds between a drug molecule and its target protein can enhance the binding affinity and specificity of the interaction, leading to more effective therapeutic outcomes.

Heme is not a medical term per se, but it is a term used in the field of medicine and biology. Heme is a prosthetic group found in hemoproteins, which are proteins that contain a heme iron complex. This complex plays a crucial role in various biological processes, including oxygen transport (in hemoglobin), electron transfer (in cytochromes), and chemical catalysis (in peroxidases and catalases).

The heme group consists of an organic component called a porphyrin ring, which binds to a central iron atom. The iron atom can bind or release electrons, making it essential for redox reactions in the body. Heme is also vital for the formation of hemoglobin and myoglobin, proteins responsible for oxygen transport and storage in the blood and muscles, respectively.

In summary, heme is a complex organic-inorganic structure that plays a critical role in several biological processes, particularly in electron transfer and oxygen transport.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Bacteria are single-celled microorganisms that are among the earliest known life forms on Earth. They are typically characterized as having a cell wall and no membrane-bound organelles. The majority of bacteria have a prokaryotic organization, meaning they lack a nucleus and other membrane-bound organelles.

Bacteria exist in diverse environments and can be found in every habitat on Earth, including soil, water, and the bodies of plants and animals. Some bacteria are beneficial to their hosts, while others can cause disease. Beneficial bacteria play important roles in processes such as digestion, nitrogen fixation, and biogeochemical cycling.

Bacteria reproduce asexually through binary fission or budding, and some species can also exchange genetic material through conjugation. They have a wide range of metabolic capabilities, with many using organic compounds as their source of energy, while others are capable of photosynthesis or chemosynthesis.

Bacteria are highly adaptable and can evolve rapidly in response to environmental changes. This has led to the development of antibiotic resistance in some species, which poses a significant public health challenge. Understanding the biology and behavior of bacteria is essential for developing strategies to prevent and treat bacterial infections and diseases.

Site-directed mutagenesis is a molecular biology technique used to introduce specific and targeted changes to a specific DNA sequence. This process involves creating a new variant of a gene or a specific region of interest within a DNA molecule by introducing a planned, deliberate change, or mutation, at a predetermined site within the DNA sequence.

The methodology typically involves the use of molecular tools such as PCR (polymerase chain reaction), restriction enzymes, and/or ligases to introduce the desired mutation(s) into a plasmid or other vector containing the target DNA sequence. The resulting modified DNA molecule can then be used to transform host cells, allowing for the production of large quantities of the mutated gene or protein for further study.

Site-directed mutagenesis is a valuable tool in basic research, drug discovery, and biotechnology applications where specific changes to a DNA sequence are required to understand gene function, investigate protein structure/function relationships, or engineer novel biological properties into existing genes or proteins.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Temperature, in a medical context, is a measure of the degree of hotness or coldness of a body or environment. It is usually measured using a thermometer and reported in degrees Celsius (°C), degrees Fahrenheit (°F), or kelvin (K). In the human body, normal core temperature ranges from about 36.5-37.5°C (97.7-99.5°F) when measured rectally, and can vary slightly depending on factors such as time of day, physical activity, and menstrual cycle. Elevated body temperature is a common sign of infection or inflammation, while abnormally low body temperature can indicate hypothermia or other medical conditions.

Dimethylamine is an organic compound with the formula (CH3)2NH. It is a colorless gas that is highly soluble in water and polar solvents. Dimethylamine is a derivative of ammonia (NH3) in which two hydrogen atoms are replaced by methyl groups (CH3).

Dimethylamines, in medical terminology, typically refer to compounds that contain the functional group -N(CH3)2. These compounds can have various biological activities and may be used as drugs or therapeutic agents. For example, dimethylamine is a metabolite of choline, a nutrient important for brain function.

However, it's worth noting that "dimethylamines" is not typically used as a medical term to describe a specific condition or diagnosis. If you have any concerns about exposure to dimethylamine or its potential health effects, it would be best to consult with a healthcare professional.

Chloroplasts are specialized organelles found in the cells of green plants, algae, and some protists. They are responsible for carrying out photosynthesis, which is the process by which these organisms convert light energy from the sun into chemical energy in the form of organic compounds, such as glucose.

Chloroplasts contain the pigment chlorophyll, which absorbs light energy from the sun. They also contain a system of membranes and enzymes that convert carbon dioxide and water into glucose and oxygen through a series of chemical reactions known as the Calvin cycle. This process not only provides energy for the organism but also releases oxygen as a byproduct, which is essential for the survival of most life forms on Earth.

Chloroplasts are believed to have originated from ancient cyanobacteria that were engulfed by early eukaryotic cells and eventually became integrated into their host's cellular machinery through a process called endosymbiosis. Over time, chloroplasts evolved to become an essential component of plant and algal cells, contributing to their ability to carry out photosynthesis and thrive in a wide range of environments.

Medical definitions of water generally describe it as a colorless, odorless, tasteless liquid that is essential for all forms of life. It is a universal solvent, making it an excellent medium for transporting nutrients and waste products within the body. Water constitutes about 50-70% of an individual's body weight, depending on factors such as age, sex, and muscle mass.

In medical terms, water has several important functions in the human body:

1. Regulation of body temperature through perspiration and respiration.
2. Acting as a lubricant for joints and tissues.
3. Facilitating digestion by helping to break down food particles.
4. Transporting nutrients, oxygen, and waste products throughout the body.
5. Helping to maintain healthy skin and mucous membranes.
6. Assisting in the regulation of various bodily functions, such as blood pressure and heart rate.

Dehydration can occur when an individual does not consume enough water or loses too much fluid due to illness, exercise, or other factors. This can lead to a variety of symptoms, including dry mouth, fatigue, dizziness, and confusion. Severe dehydration can be life-threatening if left untreated.

The term "Theoretical Models" is used in various scientific fields, including medicine, to describe a representation of a complex system or phenomenon. It is a simplified framework that explains how different components of the system interact with each other and how they contribute to the overall behavior of the system. Theoretical models are often used in medical research to understand and predict the outcomes of diseases, treatments, or public health interventions.

A theoretical model can take many forms, such as mathematical equations, computer simulations, or conceptual diagrams. It is based on a set of assumptions and hypotheses about the underlying mechanisms that drive the system. By manipulating these variables and observing the effects on the model's output, researchers can test their assumptions and generate new insights into the system's behavior.

Theoretical models are useful for medical research because they allow scientists to explore complex systems in a controlled and systematic way. They can help identify key drivers of disease or treatment outcomes, inform the design of clinical trials, and guide the development of new interventions. However, it is important to recognize that theoretical models are simplifications of reality and may not capture all the nuances and complexities of real-world systems. Therefore, they should be used in conjunction with other forms of evidence, such as experimental data and observational studies, to inform medical decision-making.

Molecular structure, in the context of biochemistry and molecular biology, refers to the arrangement and organization of atoms and chemical bonds within a molecule. It describes the three-dimensional layout of the constituent elements, including their spatial relationships, bond lengths, and angles. Understanding molecular structure is crucial for elucidating the functions and reactivities of biological macromolecules such as proteins, nucleic acids, lipids, and carbohydrates. Various experimental techniques, like X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM), are employed to determine molecular structures at atomic resolution, providing valuable insights into their biological roles and potential therapeutic targets.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

Macromolecular substances, also known as macromolecules, are large, complex molecules made up of repeating subunits called monomers. These substances are formed through polymerization, a process in which many small molecules combine to form a larger one. Macromolecular substances can be naturally occurring, such as proteins, DNA, and carbohydrates, or synthetic, such as plastics and synthetic fibers.

In the context of medicine, macromolecular substances are often used in the development of drugs and medical devices. For example, some drugs are designed to bind to specific macromolecules in the body, such as proteins or DNA, in order to alter their function and produce a therapeutic effect. Additionally, macromolecular substances may be used in the creation of medical implants, such as artificial joints and heart valves, due to their strength and durability.

It is important for healthcare professionals to have an understanding of macromolecular substances and how they function in the body, as this knowledge can inform the development and use of medical treatments.

A bacterial gene is a segment of DNA (or RNA in some viruses) that contains the genetic information necessary for the synthesis of a functional bacterial protein or RNA molecule. These genes are responsible for encoding various characteristics and functions of bacteria such as metabolism, reproduction, and resistance to antibiotics. They can be transmitted between bacteria through horizontal gene transfer mechanisms like conjugation, transformation, and transduction. Bacterial genes are often organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule.

It's important to note that the term "bacterial gene" is used to describe genetic elements found in bacteria, but not all genetic elements in bacteria are considered genes. For example, some DNA sequences may not encode functional products and are therefore not considered genes. Additionally, some bacterial genes may be plasmid-borne or phage-borne, rather than being located on the bacterial chromosome.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the ... Light-harvesting complex Photosynthesis Photosystem Phycobilisome Photosynthetic reaction center protein family Berg JM, ... "Evolution of photosynthetic reaction centers: insights from the structure of the heliobacterial reaction center". ... The reaction center found in Rhodopseudomonas bacteria is currently best understood, since it was the first reaction center of ...
The D1 and D2 proteins occur as a heterodimer that form the reaction core of PSII, a multisubunit protein-pigment complex ... Photosynthetic reaction centre proteins are main protein components of photosynthetic reaction centres (RCs) of bacteria and ... IPR005867 Photosystem II reaction centre protein PsbD/D2 InterPro: IPR005868 Photosynthetic reaction centre, L subunit InterPro ... "Evolution of photosynthetic reaction centers: insights from the structure of the heliobacterial reaction center". ...
This membrane protein complex, called a photosynthetic reaction center, was known to play a crucial role in initiating a simple ... "Structure of the protein subunits in the photosynthetic reaction centre of Rhodopseudomonas viridis at 3Å resolution". Nature. ... Deisenhofer determined the three-dimensional structure of a protein complex found in certain photosynthetic bacteria. ... Deisenhofer, J.; Epp, O.; Miki, K.; Huber, R.; Michel, H. (1984). "X-ray structure analysis of a membrane protein complex". ...
This membrane protein complex, called a photosynthetic reaction center, was known to play a crucial role in initiating a simple ... "Structure of the protein subunits in the photosynthetic reaction centre of Rhodopseudomonas viridis at 3Å resolution". Nature. ... Deisenhofer determined the three-dimensional structure of a protein complex found in certain photosynthetic bacteria. ... a membrane-bound complex of proteins and co-factors that is essential to photosynthesis. Born in Bavaria, Deisenhofer earned ...
... palustris has genes that encode for proteins that make up light-harvesting complexes (LHCs) and photosynthetic reaction centers ... LHCs and photosynthetic reaction centers are typically found in photosynthetic organisms such as green plants. Moreover, R. ... in Chlorophyll and replaces it with its Vanadium center in order to attach and harvest energy via Light Harvesting Complexes ... R. palustris also has genes that encode for the protein ruBisCO, an enzyme necessary for carbon dioxide fixation in plants and ...
While carotenoids can be found complexed within chlorophyll-binding proteins such as the photosynthetic reaction centers and ... Pigment-protein complexes that are outside of the photosynthetic system are less common, but have a simpler structure. For ... In lobsters, there are various types of astaxanthin-protein complexes present. The first one is crustacyanin (max 632 nm), a ... Astaxanthin's color is formed by creating complexes with proteins in a certain order. For example, the crustochrin has ...
The complexes consist of proteins and photosynthetic pigments and surround a photosynthetic reaction center to focus energy, ... The LH1 complexes surrounds the reaction centre, while the LH2 complexes are arranged around the LH1 complexes and the reaction ... Photosynthesis Photosynthetic reaction center Photosystem II light-harvesting protein Light harvesting pigment Fassioli, ... A light-harvesting complex consists of a number of chromophores which are complex subunit proteins that may be part of a larger ...
1996 marked the publication of Schulten's model of the LH2 structure of the photosynthetic reaction centre protein family of ... 2015). Why More Is Different Philosophical Issues in Condensed Matter Physics and Complex Systems. Berlin Heidelberg: Springer- ... Schulten recognized that a successful attack on modeling the photosynthetic reaction center would require parallel computing ... Huber won the Nobel Prize in chemistry for determining the three-dimensional structure of the photosynthetic reaction center. ...
... bacteria are protein complexes responsible for the transfer of solar energy to the photosynthetic reaction centre. Purple ... also known as the core antenna complex) that is directly associated with the reaction centre, with the RC at the center of its ... It is one of the many independent types of light-harvesting complex used by various photosynthetic organisms. In photosynthetic ... Both the alpha and the beta chains of antenna complexes are small proteins of 42 to 68 residues which share a three-domain ...
... photosynthetic reaction center complex proteins MeSH D08.811.600.710.249 - light-harvesting protein complexes MeSH D08.811. ... photosystem i protein complex MeSH D08.811.600.710.750 - photosystem ii protein complex MeSH D08.811.600.715 - polyketide ... electron transport chain complex proteins MeSH D08.811.600.250.500 - electron-transferring flavoproteins MeSH D08.811.600.250. ... glycine decarboxylase complex h-protein MeSH D08.811.600.391.200 - glycine dehydrogenase (decarboxylating) MeSH D08.811.600.465 ...
Bacterial photosynthetic reaction centres and photosystems I and II Light harvesting complexes from bacteria and chloroplasts 4 ... Family 1.G.11 Poxvirus Cell Entry Protein Complex (PEP-C) Family 1.G.12 The Avian Leukosis Virus gp95 Fusion Protein (ALV-gp95 ... HBV-S Protein) Family 1.G.7 The Reovirus FAST Fusion Protein (R-FAST) Family 1.G.8 The Arenavirus Fusion Protein (AV-FP) Family ... Transport proteins, Transmembrane proteins, Protein classification, Biological databases). ...
Bacterial photosynthetic reaction centres and photosystems I and II Light-harvesting complexes from bacteria and chloroplasts ... In humans, 27% of all proteins have been estimated to be alpha-helical membrane proteins. Beta-barrel proteins are so far found ... A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many ... Membrane Proteins of known 3D Structure Elofsson, Arne; Heijne, Gunnar von (7 June 2007). "Membrane Protein Structure: ...
... and reaction centre components in the thylakoid membrane include a water-soluble peridinin-chlorophyll a-protein complex (PCP ... photosynthetic electron transport systems such as the photosystem II reaction centre and the chlorophyll-a-P700 reaction centre ... Response of chlorophyll-protein complexes to different photon-flux densities". Marine Biology. 130 (1): 23-33. doi:10.1007/ ... Spectroscopic properties of the Chlorophyll a-Chlorophyll c2-Peridinin-Protein-Complex (acpPC) from the coral symbiotic ...
The binding of the PsaC subunit to the PsaA and PsaB subunits of the photosynthetic reaction center, Photosystem I, has been ... "The Assembly of a Multisubunit Photosynthetic Membrane Protein Complex: A Site-Specific Spin Labeling EPR Spectroscopic Study ... The theory of SDSL is based on the specific reaction of spin labels with amino acids. A spin label's built-in protein structure ... The assembly of multi-subunit membrane protein complexes has also been studied using spin labeling. ...
... and similar proteins in the photosynthetic reaction center. The endosymbiotic theory suggests that photosynthetic bacteria were ... This complex is made up of a series of proteins with different pigments which surround the reaction center. As carbon dioxide ... DNA in chloroplasts codes for redox proteins such as those found in the photosynthetic reaction centers. The CoRR Hypothesis ... the process always begins when energy from light is absorbed by proteins called reaction centers that contain photosynthetic ...
PSII is a multisubunit protein-pigment complex containing polypeptides bound to the photosynthetic membrane. Within the core of ... which pass the excitation energy on to the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind all the redox- ... Photosystem II (PSII) has a P680 reaction centre containing chlorophyll 'a' that uses light energy to carry out the oxidation ( ... Photosystem I (PSI) has a P700 reaction centre containing chlorophyll that takes the electron and associated hydrogen donated ...
... needed to drive this electron transport chain come from light-gathering proteins called photosynthetic reaction centres. ... In animals, these reactions involve complex organic molecules that are broken down to simpler molecules, such as carbon dioxide ... Reaction centers are classified into two types depending on the nature of photosynthetic pigment present, with most ... This process uses the ATP and NADPH produced by the photosynthetic reaction centres, as described above, to convert CO2 into ...
... and similar proteins in the photosynthetic reaction center. The endosymbiotic theory suggests that photosynthetic bacteria were ... contributing to more complex morphogenesis of land plants. Evolutionary history of plants Annual vs. perennial plant evolution ... DNA in chloroplasts codes for redox proteins such as photosynthetic reaction centers. The CoRR hypothesis proposes that this Co ... Therefore, chloroplasts may be photosynthetic bacteria that adapted to life inside plant cells. Like mitochondria, chloroplasts ...
ATP synthase large DNA and protein complexes: nucleosome centriole and microtubule-organizing center (MTOC) cytoskeleton ... Purple bacteria have "chromatophores", which are reaction centers found in invaginations of the cell membrane. Green sulfur ... which are photosynthetic antenna complexes found bonded to cell membranes. Cyanobacteria have internal thylakoid membranes for ... Such cell structures include: large RNA and protein complexes: ribosome, spliceosome, vault large protein complexes: proteasome ...
Each transmembrane reaction center complex is associated with an antenna complex that has hundreds of light-harvesting pigment ... This was significant because it showed that it was possible to produce these proteins in situ where they could be used as ... In fact, a common feature of all photosynthetic machinery in bacteria, algae and plants is the existence of many antenna ... complexes that can absorb the light and transfer it to a transmembrane reaction center complex. The light-harvesting pigment ...
Reaction centers are multi-protein complexes found within the thylakoid membrane. At the heart of a photosystem lies the ... "Evolution of photosynthetic reaction centers: insights from the structure of the heliobacterial reaction center". ... At the reaction center, there are many polypeptides that are surrounded by pigment proteins. At the center of the reaction ... and a reaction center. The antenna complex is where light is captured, while the reaction center is where this light energy is ...
The PSII oxygen-evolving complex (OEC) provides electrons to re-reduce the PSII reaction center, and oxidizes 2 water molecules ... is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane. ... which pass the excitation energy on to chlorophylls in the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind ... In oxygen-evolving reaction centers, more than half of the cyt b559 is in the HP form. In manganese-depleted non-oxygen ...
... complex functions to mediate the transfer of electrons and of energy between the two photosynthetic reaction center complexes, ... Iron-sulfur proteins, Light reactions, Integral membrane proteins, EC 1.10.99). ... The reaction is analogous to the reaction catalyzed by cytochrome bc1 (Complex III) of the mitochondrial electron transport ... In a separate reaction, the cytochrome b6f complex plays a central role in cyclic photophosphorylation, when NADP+ is not ...
... role of electron shuttles in the cyclic electron flow between the photosynthetic reaction center and the cytochrome bc1 complex ... "Crystal structures of photosynthetic reaction center and high-potential iron-sulfur protein from Thermochromatium tepidum: ... HiPIPs take part in many oxidizing reactions in creatures, and are especially known with photosynthetic anaerobic bacteria, ... In contrast, the protein associated with the Fd's allows these clusters to contact solvent resulting in 8 protein H-bonding ...
Light-harvesting complexes are involved in the energy transfer to the reaction centre. These are integral membrane protein ... the photosynthetic unit which is composed by the light-harvesting complexes LHI and LHII and the photosynthetic reaction centre ... Light-harvesting complexes surrounding a reaction centre (RC) harvest photons in the form of resonance energy, exciting ... LHI is directly associated with the reaction centre forming a polymeric ring-like structure around it. LHI has an absorption ...
These genes code for photosynthetic reaction centers and other components of the photosynthetic electron transport chain. A ... genes most commonly retained in mitochondrial DNA fulfil central roles in the structure of their respective protein complexes, ... Most genes for proteins of chloroplasts and mitochondria are, however, now located on chromosomes in the nuclei of eukaryotic ... Different products of protein synthesis in isolated chloroplasts and mitochondria are obtained in the presence of redox ...
... of all proteins in the cell. Metals are known to be involved in over 40% of enzymatic reactions, and metal-binding proteins ... The incorporation of a manganese center in photosystem II was highly significant, as it allowed for photosynthetic oxygen ... The incorporation of Mn in proteins allowed the complexes the ability to reduce reactive oxygen species in Mn-superoxide ... They belong to a class of enzymes with a mononuclear Mo center and they catalyze the metabolism reaction of C, N, S, etc., in ...
Photosynthetic reaction center Pairs of bacteriochlorophylls (green) inside the membrane capture energy from sunlight, then ... Heterotrimeric G proteins 1996 - Green fluorescent protein 1996 - CDK/cyclin complex 1996 - Kinesin motor protein 1997 - GroEL/ ... Crystal structures of protein and nucleic acid molecules and their complexes are central to the practice of most parts of ... 1986 - Repressor/DNA interactions 1987 - Major histocompatibility complex' 1987 - Ubiquitin 1987 - ROP protein 1989 - HIV-1 ...
... that are carried out through pigment-protein complexes (e.g. Photosystem II). Pigment-protein complexes (PPC) contain ... The light-driven charge separation process occurs at the reaction center due to the cooperation of two porphyrin derivatives. ... The dynamic and efficient antenna complexes that are present in photosynthetic organisms has inspired the design of synthetic ... are light harvesting complex 1 and light harvesting complex 2. Light harvesting complex 2 in the purple bacteria Rhodoblastus ...
... photosynthetic reaction centers). There, the electric field which is formed in the reaction center, following the light induced ... such as proteins. The photoacoustic immunoassay labels and detects target proteins using nanoparticles that can generate strong ... The second mechanism shows up in photosynthetically active sub-cell complexes in suspension (e.g. ... The photoacoustic signal from preparations which carry out the primary electron transfer reactions (e.g. reaction centers) is a ...
A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the ... Light-harvesting complex Photosynthesis Photosystem Phycobilisome Photosynthetic reaction center protein family Berg JM, ... "Evolution of photosynthetic reaction centers: insights from the structure of the heliobacterial reaction center". ... The reaction center found in Rhodopseudomonas bacteria is currently best understood, since it was the first reaction center of ...
... see PHOTOSYNTHETIC REACTION CENTER COMPLEX PROTEINS 1999-2008. History Note:. 2009; use PHOTOSYNTHETIC REACTION CENTER COMPLEX ... not for plant photosynthetic apparatus, use PHOTOSYNTHETIC REACTION CENTER, PLANT see PHOTOSYNTHETIC REACTION CENTER COMPLEX ... Plant proteins that mediate LIGHT SIGNAL TRANSDUCTION. They are involved in PHOTOTROPISM and other light adaption responses ... Plant proteins that mediate LIGHT SIGNAL TRANSDUCTION. They are involved in PHOTOTROPISM and other light adaption responses ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins. Photosynthetic Reaction Center, Plant. Photosynthetic Reaction Center Complex ... Pregnancy-Associated beta-Plasma Protein. Pregnancy-Specific beta 1-Glycoprotein. D15 - CENTRAL NERVOUS SYSTEM AGENTS. Anti- ... Photosynthetic Reaction Center, Bacterial. ... Salivary Proteins. Pregnancy Zone Proteins. Pregnancy Proteins ... D12 - AMINO ACIDS, PEPTIDES, AND PROTEINS. Parotin. ... Proteins. D10 - LIPIDS AND ANTILIPEMIC AGENTS. Lipids and ...
Photosynthetic Reaction Center Complex Proteins 92% * dimers 89% * antennas 86% * ATP-induced conformational dynamics in the ... tmRNA-SmpB complex mimics native aminoacyl-tRNAs in the A site of stalled ribosomes. Cheng, K., Ivanova, N., Scheres, S. H. W. ... Programmer, Centre for Environmental and Climate Science (CEC). *Programmer, MERGE: ModElling the Regional and Global Earth ... In situ high-resolution structure of the baseplate antenna complex in Chlorobaculum tepidum. Toudahl Nielsen, J., Kulminskaya, ...
Photosynthetic Reaction Center Complex Proteins 100% * Galactolipids 94% * Thylakoids 85% * Chloroplasts 75% ... Direct injection of pigment-protein complexes and membrane fragments suspended in water from phototrophs to C18 HPLC. Takaichi ... Orthogenomics of photosynthetic organisms: Bioinformatic and experimental analysis of chloroplast proteins of endosymbiont ... Role of galactolipid biosynthesis in coordinated development of photosynthetic complexes and thylakoid membranes during ...
Photosynthetic Reaction Center Complex Proteins 100% * photosynthetic reaction centers 81% * marine environment 62% ... Viral photosynthetic reaction center genes and transcripts in the marine environment. Sharon, I., Tzahor, S., Williamson, S., ... Meroz, Y. & Horn, D., 1 Aug 2008, In: Proteins: Structure, Function and Genetics. 72, 2, p. 606-612 7 p.. Research output: ... Motif extraction and protein classification. Kunik, V., Solan, Z., Edelman, S., Ruppin, E. & Horn, D., 2005, Proceedings - 2005 ...
Photosynthetic Reaction Center Complex Proteins 10% * Superoxides 8% * Temperature 19% * X-Ray Diffraction 10% ...
Enzymes: multienzyme complexes. Photosynthesis. *Photosynthetic reaction center complex proteins. *Photosystem *I. *II ... "Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).. *↑ Spiekerkoetter, U; Khuchua, Z; Yue, Z; Bennett, MJ; Strauss, AW ( ... The encoded protein can also bind RNA and decreases the stability of some mRNAs. The genes of the alpha and beta subunits of ... The HADHB protein catalyzes the final step of beta-oxidation, in which 3-ketoacyl CoA is cleaved by the thiol group of another ...
Bacterial Reaction centers (bRCs) from photosynthetic bacteria are pigment-protein complexes responsible for initial charge ... 2D POLIM on protein aggregation. *Tracking energy transfer and charge separation within photosynthetic unit of green non-sulfur ... Energy and electron transfer in bacterial reaction centers. *Ultrafast coherence transfer in DNA-templated silver nanoclusters ... Exciton structure, energy transfer and coherence dynamics in the FMO complex. *Spectroscopy at the nanoscale in perovskite ...
Light-Harvesting Protein Complexes, Nitrogen, Oryza, Oxidation-Reduction, Photosynthesis, Photosynthetic Reaction Center ...
... wild-type plants and photomorphogenic mutants showed large differences in their maximum photosynthetic rate and chlorophyll a/b ... The regulation by light of the composition of the photosynthetic apparatus was investigated in Arabidopsis thaliana (L.) Heynh ... Light-Harvesting Protein Complexes, Mutation, Photoreceptor Cells, Photosynthetic Reaction Center Complex Proteins, Photosystem ... The regulation by light of the composition of the photosynthetic apparatus was investigated in Arabidopsis thaliana (L.) Heynh ...
Photosynthetic Reaction Center Complex Proteins D12.776.543.983.500 D12.776.543.930.500 Photosystem I Protein Complex D12.776. ... ELAV Proteins D12.776.641.520 D12.776.631.520 ELAV-Like Protein 2 D12.776.641.520.500 D12.776.631.520.500 ELAV-Like Protein 3 ... PrP 27-30 Protein D12.776.785.700.700 D12.776.785.340.750.700 PrPC Proteins D12.776.785.680 D12.776.785.340.500 PrPSc Proteins ... Photosystem II Protein Complex D12.776.543.983.500.750 D12.776.543.930.500.750 Phototrophic Processes G2.111.87.678 G2.111.669 ...
Photosynthetic Reaction Center Complex Proteins, Quantitative Trait Loci. Abstract. Winterhardiness has three primary ...
Photosynthetic reaction center complex proteins/metabolism * Photosystem I protein complex * Proteins/genetics ... Pulse-chase labeling of cell proteins shows that the PSI reaction center subunits are synthesized normally but turn over ... Biochemical analysis indicates that neither PSI reaction center subunits nor the seven small subunits belonging to PSI ... We conclude that the iron sulfur binding protein encoded by the psaC gene is an essential component, both for photochemical ...
The apparatus consists of up to four types of pigment-protein complexes: (i) the photosynthetic reaction center surrounded by ( ... is transferred between the pigment-protein complexes until it is used for the primary photoreaction in the reaction center. We ... Substitution of LH2 complexes by LH3 complexes or changing an architecture in which few LH2 (LH3) complexes are in contact with ... Pigment-protein complexes are found to form an excitation reservoir, in which excitation is spread over many chromophores ...
A protein complex which receives the light energy trapped by chlorophyll, bacteriochlorophyll and accessory pigments and ... Fields of Study , biochemistry , metabolism , energy metabolism , photosynthesis , photosynthetic reaction centers. Fields of ... Fields of Study , biochemistry , metabolism , carbohydrate metabolism , photosynthesis , photosynthetic reaction centers. ... Fields of Study , physiology , metabolism , carbohydrate metabolism , photosynthesis , photosynthetic reaction centers. ...
Photosynthetic Reaction Center Complex Proteins [D08.811.600.710] * Polyketide Synthases [D08.811.600.715] * Prostaglandin- ... Multienzyme Complexes [D08.811.600] * Anthranilate Phosphoribosyltransferase [D08.811.600.075] * Anthranilate Synthase [D08.811 ... Mi-2 Nucleosome Remodeling and Deacetylase Complex [D08.811.600.620] * Phosphoenolpyruvate Sugar Phosphotransferase System [ ...
... reaction center (RC) proteins, or a core complex consisting of the RC encircled by light harvesting (LH1) proteins (RC-LH1) ... reaction center (RC) proteins, or a core complex consisting of the RC encircled by light harvesting (LH1) proteins (RC-LH1) ... Bio-Phototransistors with Immobilized Photosynthetic Proteins Takshi, Arash; Yaghoubi, Houman; Jun, Daniel; Beatty, J. Thomas, ... The efficient mechanism of light capture by photosynthetic proteins allows for energy transfer and conversion to ...
There are two main constituent proteins in the core complex: light-harvesting complex I (LH1) and the reaction center (RC). The ... Some proteins can even hold two different jobs. One example of a dual-duty protein is the bacterial photosynthetic core complex ... A model of the Core Complex-Only Photosynthetic Membrane In the absence of the light-harvesting complex II, the core complex ... In photosynthetic bacteria, these two steps are carried out in the large membrane protein assembly called the photosynthetic ...
This complex, the so called reaction centre of the photosynthesis, was isolated by him from the purple bacteria ... "for the determination of the three-dimensional structure of a photosynthetic reaction centre."[1] ... Michel succeeded in the crystallization of several membrane proteins, especially in the year 1981 of the central complex, which ... From thereon he was convinced that it was possible to create crystalized membrane proteins, an assumption that was considered ...
  • A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the primary energy conversion reactions of photosynthesis. (wikipedia.org)
  • Bacterial Reaction centers (bRCs) from photosynthetic bacteria are pigment-protein complexes responsible for initial charge separation steps of photosynthesis. (lu.se)
  • Michel succeeded in the crystallization of several membrane proteins, especially in the year 1981 of the central complex, which is responsible for the primary separation of electronic charges and for the transport of electrons over the photosynthetic membrane during the Photosynthesis. (uni-wuerzburg.de)
  • This complex, the so called reaction centre of the photosynthesis, was isolated by him from the purple bacteria Rhodopseudomonas viridis. (uni-wuerzburg.de)
  • The thylakoid membrane is the site of the light reactions of photosynthesis. (flashcardmachine.com)
  • Photosynthesis begins with the absorption of light energy by the chlorophyll pigments of the light-harvesting antennae ( Light Harvesting Complexes - LHC - composed of proteins and chlorophyll and carotenoid pigments). (cea.fr)
  • Light reaction of photosynthesis is one of the most important reactions for sustaining our environment. (elifesciences.org)
  • Scientists used to believe that photosystem I, the membrane protein complex present in all aerobic organisms, utilized a form of chlorophyll called chlorophyll a for photosynthesis. (riken.jp)
  • How A. marina uses low-energy light for photosynthesis has been a long-standing question," notes Koji Yonekura, who leads the Biostructural Mechanism Group at the RIKEN SPring-8 Center. (riken.jp)
  • 2. Photosynthetic pigments: Types, spectral properties, functions in photosynthesis. (elte.hu)
  • Previous experiments led by Graham Fleming, a physical chemist holding joint appointments with Berkeley Lab and UC Berkeley, pointed to quantum mechanical effects as the key to the ability of green plants, through photosynthesis, to almost instantaneously transfer solar energy from molecules in light harvesting complexes to molecules in electrochemical reaction centers. (lbl.gov)
  • We present strong evidence for quantum entanglement in noisy non-equilibrium systems at high temperatures by determining the timescales and temperatures for which entanglement is observable in a protein structure that is central to photosynthesis in certain bacteria," Sarovar says. (lbl.gov)
  • For a long time, improving the efficiency of photosynthesis by artificial modification of photosynthetic proteins and pathways has been considered impossible or unrealistic. (scar.ac.cn)
  • Over evolutionary time, photosynthesis has become complex and tightly regulated. (scar.ac.cn)
  • Recently, core photosystem II (PSII) genes were identified in cyanophages and proposed to function in photosynthesis and in increasing viral fitness by supplementing the host production of these proteins. (nih.gov)
  • Primary steps of the photosynthesis, such as photon absorption, are going inside the protein complexes named as light-harvesting antenna, and processing extremely fast - at the timescales from tens of femtoseconds (10 -15 s) to tens of picoseconds (10 -12 s). (polivkalab.cz)
  • In cyanobacteria, which are prokaryotes performing oxygenic photosynthesis, solar energy is absorbed by the large extramembrane complex, phycobillisome. (polivkalab.cz)
  • The basic function of the light reactions of photosynthesis is the conversion of solar energy to chemical energy. (goldenssport.com)
  • Select the most accurate statement describing the basic function of the light reactions of photosynthesis. (goldenssport.com)
  • In the dinoflagellate symbiont, the proteomic response to low pH was characterised by the relative over-abundance of photosynthesis-related proteins. (wgtn.ac.nz)
  • However, under low light conditions, their growth rate was significantly reduced as compared with the wild-type, due to a lowered efficiency of the light reaction of photosynthesis. (silverchair.com)
  • The vast majority of plastid genome-encoded genes can be grouped into two classes: genetic system genes (rRNAs, tRNAs, ribosomal proteins, subunits of an Escherichia coli -like RNA polymerase) and photosynthesis genes (subunits of the photosystems I and II, the cytochrome b 6 f complex, the ATP synthase, large subunit of Rubisco). (silverchair.com)
  • At the heart of Photosynthesis, the pigment-protein complex photosystem II reaction center (PSII RC), performs charge separation with near unity quantum efficiency despite its highly disordered energy landscape, and thus converts sunlight to electrochemical energy. (uam.es)
  • The reaction center contains two pigments that serve to collect and transfer the energy from photon absorption: BChl and Bph. (wikipedia.org)
  • A protein complex which receives the light energy trapped by chlorophyll, bacteriochlorophyll and accessory pigments and inititates the electron transfer process that transduces the light energy to ATP. (usda.gov)
  • The light-absorption function of the LH1 is carried out by pigments (bacteriochlorophylls, abbreviated as BChls) embedded in the protein. (uiuc.edu)
  • The rate of such energy transfer is dependent on the geometry of the pigment organization, which in turn is defined largely by protein geometry, since pigments are fixated at certain preferred binding sites. (uiuc.edu)
  • Previous ensemble studies have shown that cyanobacteria respond to changes in nutrient availability by modifying the structure of PBS complexes, but this process has not been visualized for individual pigments at the single-cell level due to spectral overlap. (osti.gov)
  • We characterized the response of four key photosynthetic pigments to nitrogen depletion and repletion at the subcellular level in individual, live Synechocystis sp. (osti.gov)
  • The light harvesting complex is composed of trimeric and monomeric antenna proteins containing Chlorophyll a and b pigments and Carotenoids. (unine.ch)
  • Whether in vivo or in vitro , the Laboratory of Bioenergetics, Metalloproteins and Stress ( I2BC department), led by Bruno Robert, has shown that this quenching is linked to a rearrangement of the proteins and pigments that build the LHC, which creates energy traps . (cea.fr)
  • The researchers' analysis revealed that one of the light-harvesting pigments is pheophytin a , a metal-free chlorin that differs from other type I reaction centers. (riken.jp)
  • 3. Evolution of photosynthetic pigments. (elte.hu)
  • Several types of pigments-such as chlorophylls, carotenoids, and phycobilins-serve this function in various photosynthetic organisms. (scar.ac.cn)
  • In the majority of LH complexes, however, two types of pigments serve as light-capturing agents: (bacterio)chlorophylls [(B)Chls] and carotenoids. (polivkalab.cz)
  • Not all pigments bound in protein are involved in light-harvesting and energy transfer. (polivkalab.cz)
  • The two photosystems absorb light energy through proteins containing pigments, such as chlorophyll. (goldenssport.com)
  • The respective part of photosynthetic apparatus of all photoautotrophic organisms, which is responsible of capturing light, is created by pigment-protein complexes containing chlorophyll-a and other accessorial pigments ( chlorophyll-b, phycocyanine, phycoerythrine, fucoxantine, peridinine etc.) which help to absorb the energy of light and pass it to chlorophyll-a. (cas.cz)
  • Some of other photosynthetic pigments (e.g. phycocyanines) are fluorescent themselves. (cas.cz)
  • Carotenoids are important photosynthetic pigments that play key roles in light harvesting and energy transfer, photoprotection, and in the folding, assembly, and stabilization of light-harvesting pigment-protein complexes. (uea.ac.uk)
  • The genetically tractable purple phototrophic bacteria have been useful for investigating the biosynthesis and function of photosynthetic pigments and cofactors, including carotenoids. (uea.ac.uk)
  • The regulation by light of the composition of the photosynthetic apparatus was investigated in Arabidopsis thaliana (L.) Heynh. (ox.ac.uk)
  • The present study suggests that any chloroplast gene encoding a component of the photosynthetic apparatus can be disrupted in C. reinhardtii using the strategy described. (unige.ch)
  • The apparatus consists of up to four types of pigment-protein complexes: (i) the photosynthetic reaction center surrounded by (ii) the light-harvesting complex LH1, (iii) antenna complexes LH2, which are replaced under low-light conditions by (iv) antenna complexes LH3 with a higher absorption maximum. (uiuc.edu)
  • Following absorption of light anywhere in the apparatus, electronic excitation is transferred between the pigment-protein complexes until it is used for the primary photoreaction in the reaction center. (uiuc.edu)
  • The kinetics of excitation migration in the photosynthetic apparatus is described through a master equation which connects the calculated transfer rates to the overall architecture of the apparatus. (uiuc.edu)
  • This feature permits a high quantum yield of 83% to 89%, but also protects the apparatus from overheating by spreading dissipation over all complexes. (uiuc.edu)
  • The work supports a role for chemical modification in the recognition and subsequent degradation of a key protein subunit of PSII by a bacterial-type protease, suggesting that tryptophan oxidation of components of the photosynthetic apparatus after high light stress plays a critical role in initiating the PSII repair system. (elifesciences.org)
  • Photosynthetic apparatus of all photosynthetic organisms contains two vital components needed for the light reactions: a light-harvesting (LH) antenna and a reaction center. (polivkalab.cz)
  • Moreover, the chlorophyll fluorescence changes in the time in relation to photosynthetic activity and could be used for the characterization of the status of photosynthetic apparatus in assessed algae or cyanobacteria. (cas.cz)
  • In photosynthetic organisms, maintenance of photosynthetic light reaction is manifested by so called Photosystem II (PSII) repair system, where the reaction center protein D1 is targeted to photo-oxidative damage and rapidly degraded by the processive protease FtsH. (elifesciences.org)
  • The team's findings could help us better understand how photosynthetic organisms are able to survive in extremely low-light environments, both here on Earth and potentially beyond. (riken.jp)
  • Photosynthetic organisms. (elte.hu)
  • 5. Structure and function of Q-type centers in bacterial photosynthetic organisms. (elte.hu)
  • Analysis of these mutants does not lead to a simple hypothesis of the role of this protein as the characteristics from the two organisms are not identical. (ucl.ac.uk)
  • All photosynthetic organisms contain carotenoids. (polivkalab.cz)
  • Unlike reaction centers, LH complexes exhibit a large variability among photosynthetic organisms. (polivkalab.cz)
  • Consequently, the carotenoids' actions in LH complexes are of vital importance for survival of photosynthetic organisms. (polivkalab.cz)
  • The projects carried out in our laboratory aims for a deeper understanding of both LH and regulatory functions of carotenoids in antenna complexes from various photosynthetic organisms. (polivkalab.cz)
  • Plastocyanin is a "blue" copper protein which catalyzes electron transfer between the cytochrome b6 .f complex and P-700, the reaction center of photosystem I. Plastocyanin is a nuclear encoded polypeptide in all eukaryotic photosynthetic organisms where it has been studied. (agrisera.com)
  • Molecular excitations, either originating directly from sunlight or transferred as excitation energy via light-harvesting antenna systems, give rise to electron transfer reactions along the path of a series of protein-bound co-factors. (wikipedia.org)
  • Development of molecular properties and reaction centers: loss of charge, appearance of apolar structures, ability to insert into membranes. (elte.hu)
  • Photosystem two is a multi subunit protein complex which carries out a photochemical reaction producing reduced plastoquinone and molecular oxygen as the products. (ucl.ac.uk)
  • It is synthesized as a pre-protein of approximate molecular weight 17,000, imported post-translationally into chloroplasts, and processed to its mature form of approximate molecular weight 10,500 within the plastid. (agrisera.com)
  • The chloroplast gene psaC encoding the iron sulfur protein of photosystem I (PSI) from the green alga Chlamydomonas reinhardtii has been cloned and characterized. (unige.ch)
  • Leaves are the primary photosynthetic organs, within which mesophyll cells differentiate to become chloroplast-filled. (biomedcentral.com)
  • The stroma also contains the ___,____, and ribosomes involved in the synthesis of several chloroplast proteins. (flashcardmachine.com)
  • Further characterization of Trp-14 using chloroplast transformation in Chlamydomonas indicated that substitution of D1 Trp-14 to Phe, mimicking Trp oxidation enhanced FtsH-mediated D1 degradation under high light, although the substitution did not affect protein stability and PSII activity. (elifesciences.org)
  • Comparison with mitochondrial and chloroplast complexes. (elte.hu)
  • It is the process by which the chloroplast thylakoids of the leaf and other photosynthetic structures harvest light. (scar.ac.cn)
  • The proteins which form this centre are encoded for by both nuclear and chloroplast genes and while the function of some has been determined, many play an unknown role. (ucl.ac.uk)
  • Green plants and algae have two different types of reaction centers that are part of larger supercomplexes known as P700 in Photosystem I and P680 in Photosystem II. (wikipedia.org)
  • Cyanobacteria, the precursor to chloroplasts found in green plants, have both photosystems with both types of reaction centers. (goldenssport.com)
  • Reaction centers are present in all green plants, algae, and many bacteria. (wikipedia.org)
  • The reaction center found in Rhodopseudomonas bacteria is currently best understood, since it was the first reaction center of known structure and has fewer polypeptide chains than the examples in green plants. (wikipedia.org)
  • In the 1960s, Roderick Clayton was the first to purify the reaction center complex from purple bacteria. (wikipedia.org)
  • The latter sub-unit is not a general structural motif in photosynthetic bacteria. (wikipedia.org)
  • Kinetics of excitation migration and trapping in the photosynthetic unit of purple bacteria. (uiuc.edu)
  • In this work, reaction center (RC) proteins, or a core complex consisting of the RC encircled by light harvesting (LH1) proteins (RC-LH1) from photosynthetic bacteria, were immobilized on an insulating layer of an ion-sensitive field-effect transistor (ISFET) to build bio-photodetectors. (ubc.ca)
  • In photosynthetic bacteria, these two steps are carried out in the large membrane protein assembly called the photosynthetic core complex. (uiuc.edu)
  • 2D electronic spectroscopy using ultrafast laser pulses throughout the visible regime was applied to study excitation energy transfer in the major light harvesting complex of photosystem II (LHCII) and the reaction center from purple bacteria. (escholarship.org)
  • Structure and function of the Q-type centers in Chloroflexus and purple bacteria, comparison with photosystem II. (elte.hu)
  • 9. Antenna complexes in algae and photosynthetic bacteria. (elte.hu)
  • Green plants and certain bacteria are able to transfer the energy harvested from sunlight through a network of light harvesting pigment-protein complexes and into reaction centers with nearly 100-percent efficiency. (lbl.gov)
  • In the case of LHCII , the main collecting antenna of higher plants, in vitro spectroscopy experiments conducted on the aggregated complex (in the absence of the detergent conventionally used to solubilise it) establish that this transfer occurs between chlorophyll a and a lutein (a carotenoid). (cea.fr)
  • Annular lipids are proposed to provide a connection for super-complex formation with the photosystem-I reaction center and the LHCII kinase enzyme for transmembrane signaling. (rcsb.org)
  • The delocalized excited states observed in the experimental and theoretical results were found to increase the range of optimal angles for energy transfer from LHCII to neighboring pigment-protein complexes, as opposed to the case of a single, isolated donor excited state. (escholarship.org)
  • Chlorophyll-proteins of LHCI and LHCII. (elte.hu)
  • The absorption profile of major plant antenna complex LHCII (green, digitised from [Kondo et al. (astrobiology.com)
  • A dimer of RC complexes receive energy by a modular assembly of LHCs, including core and minor (monomeric) antenna complexes plus LHCII trimers. (astrobiology.com)
  • Once the light energy has been absorbed directly by the pigment molecules, or passed to them by resonance transfer from a surrounding light-harvesting complex, they release electrons into an electron transport chain and pass energy to a hydrogen donor such as H2O to extract electrons and protons from it. (wikipedia.org)
  • proteins mediating electron transport and oxidative phosphorylation are bound in the inner mitochondrial membrane, so the respiration rate varies with membrane surface area. (flashcardmachine.com)
  • New results concerning water splitting (H-abstraction model), reaction center (active tetramer), quinone reduction (lipids and proton wire), and light protection (function of cytochrome b559, cyclic electron transport around photosystem II). (elte.hu)
  • This energy conversion is a complex process involving interactions between several pigment molecules and electron-transport proteins. (scar.ac.cn)
  • Electrons travel through the cytochrome b6f complex to photosystem I via an electron transport chain within the thylakoid membrane. (goldenssport.com)
  • Fe participates in cellular respiration, synthesis, and stabilization of chlorophyll, photosynthetic electron transport, and various other metabolic functions ( Grotz and Guerinot, 2006 ). (frontiersin.org)
  • A reaction center is laid out in such a way that it captures the energy of a photon using pigment molecules and turns it into a usable form. (wikipedia.org)
  • We calculate, using Forster theory, all rates for the inter-complex excitation transfer processes on the basis of the atomic level structures of the pigment-protein complexes and of an effective Hamiltonian, established previously, for intra-complex excitations. (uiuc.edu)
  • Pigment-protein complexes are found to form an excitation reservoir, in which excitation is spread over many chromophores rather than forming an excitation funnel in which excitation is transferred without detours from the periphery to the RC. (uiuc.edu)
  • Cyanobacterial phycobilisome (PBS) pigment-protein complexes harvest light and transfer the energy to reaction centers. (osti.gov)
  • Lastly, we observed differential rod and core pigment responses to nitrogen deprivation, suggesting that PBS complexes undergo a stepwise degradation process. (osti.gov)
  • Experiments using two-dimensional (2D) electronic spectroscopy to investigate the structure-function relationships that give rise to photosynthetic energy transfer within pigment protein complexes are presented and discussed in this dissertation. (escholarship.org)
  • We show that this phenotype is caused by the deficiency in a pigment-protein complex of the light-harvesting antenna of photosystem II and hence by a reduced efficiency of photon capture when light availability is limiting. (silverchair.com)
  • Our results indicate that, in contrast to the current view, light-harvesting complexes do not only consist of the classical pigment-binding proteins, but may contain small structural subunits in addition. (silverchair.com)
  • Four different subunits were found to be important for the function of the photosynthetic reaction center. (wikipedia.org)
  • The genes of the alpha and beta subunits of the mitochondrial trifunctional protein are located adjacent to each other in the human genome in a head-to-head orientation. (wikidoc.org)
  • Biochemical analysis indicates that neither PSI reaction center subunits nor the seven small subunits belonging to PSI accumulate stably in the thylakoid membranes of the transformants. (unige.ch)
  • Pulse-chase labeling of cell proteins shows that the PSI reaction center subunits are synthesized normally but turn over rapidly in the transformants. (unige.ch)
  • A) A core complex in which the LH1 subunits form a complete ring, as seen in Rhodospirillum rubrum . (uiuc.edu)
  • B) A core complex in which the LH1 subunits forms a ring with a gap, with an extra polypeptide near the gap, as seen in Rhodopseudomonas palustris . (uiuc.edu)
  • The dimeric photosynthetic cytochrome b6f complex, a 16-mer of eight distinct subunits and 26 transmembrane helices, catalyzes transmembrane proton-coupled electron transfer for energy storage. (rcsb.org)
  • These subunits appear to be crucial architectural factors for the assembly and/or maintenance of stable light-harvesting complexes. (silverchair.com)
  • The difference between the dark and light currents at different wavelengths are well-matched with the absorption spectrum of the photosynthetic proteins. (ubc.ca)
  • This absorption creates excitation energy (change from a ground electronic state to an excited state of the collecting chlorophyll ), which is transferred from one chlorophyll to the next to the photosynthetic reaction centre where it is converted into chemical potential energy (by charge separation). (cea.fr)
  • The schematic on the left shows the absorption of light by a light harvesting complex and the transport of the resulting excitation energy to the reaction center through the FMO protein. (lbl.gov)
  • Photosynthetic rates at saturating irradiance were the same in wild-type and antisense plants, but there was a 10-15% reduction in quantum yield that reflected the decrease in light absorption by the leaf. (ox.ac.uk)
  • HADHB is a subunit of the mitochondrial trifunctional protein and has thiolase activity. (wikidoc.org)
  • This gene encodes the beta subunit of the mitochondrial trifunctional protein, a catalyst of mitochondrial beta-oxidation of long chain fatty acids . (wikidoc.org)
  • Internal lipids mediate crosslinking to stabilize the domain-swapped iron-sulfur protein subunit, dielectric heterogeneity within intermonomer and intramonomer electron transfer pathways, and dimer stabilization through lipid-mediated intermonomer interactions. (rcsb.org)
  • This study provides a complete structure analysis of lipid-mediated functions in a multi-subunit membrane protein complex and reveals lipid sites at positions essential for assembly and function. (rcsb.org)
  • The final chapter discusses the nuclear encoded subunit of the PSII core, PSII-W. We report the isolation and partial sequencing of the gene for this protein in C. reinhardtii. (ucl.ac.uk)
  • 2) The damaged pheo a may be attributed to the one bonding to the D2 protein comparing the D2 subunit in the PS Ⅱ reaction center with M subunit in the purple bacterium photosynthetic reaction center. (jipb.net)
  • In the bacterial reaction center, the electron is obtained from a reduced compound haem group in a cytochrome subunit or from a water-soluble cytochrome-c protein. (goldenssport.com)
  • The orientation of the RC proteins was controlled via application of a hybrid linker made of 10-carboxydecylphosphonic acid and cytochrome c that anchored the RCs to their electron donor side. (ubc.ca)
  • After the electron has left Photosystem II it is transferred to a cytochrome b6f complex and then to plastocyanin, a blue copper protein and electron carrier. (goldenssport.com)
  • The second phase is marked by the development of photosynthetic chloroplasts which occupy the available cellular space. (biomedcentral.com)
  • Understanding the build-up of photosynthetic capacity requires detailed knowledge of how these cells, and chloroplasts within, are produced and develop. (biomedcentral.com)
  • Both reaction center types are present in chloroplasts and cyanobacteria, and work together to form a unique photosynthetic chain able to extract electrons from water, creating high-energy oxygen as a byproduct. (goldenssport.com)
  • 3) A possible arrangement model of redox cofactors in the PS Ⅱ reaction center was proposed based on our experiment. (jipb.net)
  • Potentially, the seven proteins encoded by the viral genes are sufficient to form an intact monomeric PSI complex. (nih.gov)
  • The spectroscopic properties of carotenoids, being fundamental constituents of light-harvesting complexes in marine algae, exhibit a strong dependence on the environment. (polivkalab.cz)
  • Polívka, T., Hiller, R. G., Frank, H. A. Spectroscopy of the Peridinin - Chlorophyll-a Protein: Insight into light-harvesting strategy of marine algae. (polivkalab.cz)
  • A redox-active protein that carries electrons via a prosthetic Fe-containing heme group. (flashcardmachine.com)
  • Type I photosystems use ferredoxin-like iron-sulfur cluster proteins as terminal electron acceptors, while type II photosystems ultimately shuttle electrons to a quinone terminal electron acceptor. (goldenssport.com)
  • Photosystem I is an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane from plastocyanin to ferredoxin. (goldenssport.com)
  • To achieve this amazing feat, the PSII RC exploits The Quantum Design Principles of Photosynthetic Charge Separation 1-2 , complementary and interrelated solutions to ensure rapid forward and irreversible transfer of energy and electrons within a disordered and fluctuating environment. (uam.es)
  • Reaction centers from different bacterial species may contain slightly altered bacterio-chlorophyll and bacterio-pheophytin chromophores as functional co-factors. (wikipedia.org)
  • In different bacterial species, the photosynthetic core complex can take on very different organizations. (uiuc.edu)
  • The efficient mechanism of light capture by photosynthetic proteins allows for energy transfer and conversion to electrochemical energy at very low light intensities. (ubc.ca)
  • The electrochemical water splitting reaction, which consists of hydrogen reduction at the cathode and oxygen evolution (OER) at the anode, is one of the core processes for the utilization of sustainable and green energy sources. (edu.au)
  • The LH complex absorbs light energy and funnels it into the reaction center where the charge separation takes place. (polivkalab.cz)
  • Regulatory mechanisms of photosynthetic light reactions. (elte.hu)
  • this may be evidence that photosystem stoichiometry is controlled not only by photoreceptors, but also by photosynthetic metabolism. (ox.ac.uk)
  • Moreover, modulation of the proteins involved in cellular metal homeostasis may help in the regulation of metabolism, adaptability to a diverse range of environmental conditions, and biofortification. (frontiersin.org)
  • The first step of photosynthetic electron transfer in the thylakoid membrane occurs at Photosystem II (PSII), where light energy absorbed by P 680 chlorophyll molecules drives water oxidation, and electron is transferred to plastoquinone. (elifesciences.org)
  • We employ 2DES for studying photosynthetic chromophore-protein complexes, artificial molecules and nanostructures. (lu.se)
  • The difference between Photosystem II and the bacterial reaction center is the source of the electron that neutralizes the pair of chlorophyll a molecules. (goldenssport.com)
  • Cyanobacteria of the Synechococcus and Prochlorococcus genera are important contributors to photosynthetic productivity in the open oceans. (nih.gov)
  • One of such examples, is the Orange Carotenoid Protein (OCP) found in cyanobacteria. (polivkalab.cz)
  • This was also significant for being the first 3D crystal structure of any membrane protein complex. (wikipedia.org)
  • Significance of the geometry of antennae and reaction centers. (elte.hu)
  • 8. Photosynthetic antennae in higher plants. (elte.hu)
  • 10. Hypotheses on the evolution of photosynthetic antennae. (elte.hu)
  • Reaction center origin of bacterial antennae. (elte.hu)
  • The matrix also contains the mitochondrial genetic machinery-DNA, RNA, and ribosomes-that generates several (but by no means all) mitochondrial proteins. (flashcardmachine.com)
  • Their simple structure as well as high energy and charge transfer efficiency, which are not fully understood yet, makes bRCs one of the most important and most investigated photosynthetic systems in the world. (lu.se)
  • We use methods based on chlorophyll fluorescence to analyze the photosynthetic efficiency of the plants exposed to different light conditions. (unine.ch)
  • Of particular interest is energy and electron transfer in photosynthetic light-harvesting complexes and reaction centers, which demonstrate remarkable efficiency and robustness. (lu.se)
  • While LH processes carried out by (B)Chls are understood in great detail for many antenna proteins, the functions of carotenoids in LH complexes are much less understood, mainly due to their unique excited state properties. (polivkalab.cz)
  • Besides, carotenoids also play a regulatory role in LH complexes by controlling energy flow throughout LH complexes. (polivkalab.cz)
  • However, the sluggish kinetics of the oxygen evolution reaction requires a higher overpotential than the theoretical potential (1.23 V). Engineering a high-performance electrocatalyst is an avenue to improve the reaction kinetics for OER. (edu.au)
  • It may be considered that there are two different electron transfer branches in the PS Ⅱ reaction center just as in the purple bacterium photosynthetic reaction center. (jipb.net)
  • Immune-response activation was signalled by increased abundance of alkaline phosphatases, an interferon-induced protein, collagen alpha chain, and a Golgi-associated plant pathogenesis-related protein, while HSPs, catalase and enolase indicated the upregulation of ROS management pathways. (wgtn.ac.nz)
  • Figure 2 - Structural model of the Rhodobacter sphaeroides core complex and excitation states. (uiuc.edu)
  • spectrofluorometers (see below), recording the fluorescence as a result of excitation by appropriate light wavelength, and fluorometers , which measure changes in induced chlorophyll fluorescence as a response to changes in photosynthetic activity of the organism. (cas.cz)
  • When the induced chlorophyll fluorescence technique is applied, even some information about physiological status of the phytoplankton, and especially about its photosynthetic activity can be obtained. (cas.cz)
  • The lessons we're learning about the quantum aspects of light harvesting in natural systems can be applied to the design of artificial photosynthetic systems that are even better," Sarovar says. (lbl.gov)
  • The structures of these supercomplexes are large, involving multiple light-harvesting complexes. (wikipedia.org)
  • The organic structures in light harvesting complexes and their synthetic mimics could also serve as useful components of quantum computers or other quantum-enhanced devices, such as wires for the transfer of information. (lbl.gov)
  • Here we construct general models of photosynthetic light-harvesting structures to determine how an oxygenic photosystem would perform in different irradiant spectral fluxes. (astrobiology.com)
  • Other ancient mats have been studied, but Westall says evidence that they photosynthesized has been indirect - either being assumed from their carbon-isotope composition, which Westall argues can also come from non-photosynthetic microbes, or by looking closely at the mat's structure and seeing microbe-like structures. (uncommondescent.com)
  • A small conserved open reading frame in the plastid genome, ycf9 , encodes a putative membrane protein of 62 amino acids. (silverchair.com)
  • The potential contribution of coherence to the robustness of photosynthetic energy transfer to the rugged energy landscape and to temperature variations is discussed. (escholarship.org)
  • The bacterial photosynthetic reaction center has been an important model to understand the structure and chemistry of the biological process of capturing light energy. (wikipedia.org)
  • Its role is to capture the light energy and trasfer it in the form of excitaiton to the chlorophyll of the reaction centers and to dissipate the excess of light energy when the light input overcomes the photosynthetic capacity. (unine.ch)
  • Now, Tasuku Hamaguchi, Keisuke Kawakami, Yonekura and their colleagues have shed light on this question by analyzing the structure of the photosystem I reaction center-the part of chlorophyll that converts sunlight into a form of chemical energy that can be used by the rest of the photosynthetic machinery-of chlorophyll d in A. marina (Fig. 1). (riken.jp)
  • These experiments elucidated information about the excited state structure and the energy transfer timescales within these complexes. (escholarship.org)
  • Experiments on the B band of the bacterial reaction center were able to isolate the previously inseparable two peaks and observe energy transfer between these two excited states. (escholarship.org)
  • Using this approach, energy was found to transfer from the carotenoid to the bacteriochlorophyll both via S1 and via Qx in the bacterial reaction center in an approximately 2:1 ratio, and within about 750 fs. (escholarship.org)
  • Energy transfer inside and between chlorophyll-proteins. (elte.hu)
  • Water oxidation using solar energy is carried out by Photosystem II using a catalytic Mn4 complex. (psi.ch)
  • Interprotein energy transfer (solid arrows) is 1-2 orders of magnitude slower than intra-protein relaxation (Chl b → Chl a , dashed arrow). (astrobiology.com)
  • Hypotheses about the evolution of reaction centers and their evidences (Olson, Blankenship, Vermaas models, „export model", „redox switch" hypothesis, apoprotein early model). (elte.hu)
  • Chapter one discusses the literature on the oxygen evolution reaction and Co- and Ru-based electrocatalysts for OER as well as the organic solution-phase synthesis method. (edu.au)
  • This is mainly due to current limitations in managing the inherent Li-S redox reactions which involve diffusion and migration of electrochemically active polysulfides. (edu.au)
  • First, the transfer of an electron from BPh− to P960+ is relatively slow compared to two other redox reactions in the reaction center. (goldenssport.com)
  • C) and (D) Two proposed organizations for a dimeric core complex, the dimerization of which requires the extra polypeptide, PufX. (uiuc.edu)
  • The structure of Photosystem II is remarkably similar to the bacterial reaction center, and it is theorized that they share a common ancestor. (goldenssport.com)
  • 2011), orange carotenoid protein (Polívka et al. (polivkalab.cz)
  • We provide detailed procedures for manipulating carotenoid biosynthesis, and for the preparation and analysis of the light-harvesting and photosynthetic reaction center complexes that bind them. (uea.ac.uk)
  • In addition there is dearth of informatio such that only three genera have been classified based on diverse photosynthetic pathways with no information found on the physiological and biochemical characterization of these genera. (scar.ac.cn)
  • In the Rhodobacter species, there is a similar extra protein called PufX, which causes the core complex to dimerize (Figure 1C and D) in Rhodobacter sphaeroides . (uiuc.edu)
  • Dimeric core complexes are seen in certain Rhodobacter species, the best-known case being Rhodobacter sphaeroides . (uiuc.edu)
  • A) Setup of the all-atom simulation that combined modeling with the low-resolution structural data of the Rhodobacter sphaeroides core complex. (uiuc.edu)
  • The Rhodobacter sphaeroides core complex is capable of bending the cellular membrane. (uiuc.edu)
  • It is still not completely established where the PufX protein is in the Rhodobacter sphaeroides core complex dimer. (uiuc.edu)
  • Photosystem II (PSII) is the initial site of photosynthetic electron transfer by water oxidation. (elifesciences.org)