Cellulosomes
Clostridium thermocellum
Clostridium cellulolyticum
Cellulase
Cellulose
Cellulases
Clostridium
Clostridium cellulovorans
Endo-1,4-beta Xylanases
Piromyces
Cellobiose
Xylosidases
Metabolic Engineering
Actinomycetales
Cellulose 1,4-beta-Cellobiosidase
Lignin
Multienzyme Complexes
Triticum
Carrier Proteins
Encyclopedias as Topic
Polysaccharides
Glucans
ScaC, an adaptor protein carrying a novel cohesin that expands the dockerin-binding repertoire of the Ruminococcus flavefaciens 17 cellulosome. (1/63)
A new gene, designated scaC and encoding a protein carrying a single cohesin, was identified in the cellulolytic rumen anaerobe Ruminococcus flavefaciens 17 as part of a gene cluster that also codes for the cellulosome structural components ScaA and ScaB. Phylogenetic analysis showed that the sequence of the ScaC cohesin is distinct from the sequences of other cohesins, including the sequences of R. flavefaciens ScaA and ScaB. The scaC gene product also includes at its C terminus a dockerin module that closely resembles those found in R. flavefaciens enzymes that bind to the cohesins of the primary ScaA scaffoldin. The putative cohesin domain and the C-terminal dockerin module were cloned and overexpressed in Escherichia coli as His(6)-tagged products (ScaC-Coh and ScaC-Doc, respectively). Affinity probing of protein extracts of R. flavefaciens 17 separated in one-dimensional and two-dimensional gels with recombinant cohesins from ScaC and ScaA revealed that two distinct subsets of native proteins interact with ScaC-Coh and ScaA-Coh. Furthermore, ScaC-Coh failed to interact with the recombinant dockerin module from the enzyme EndB that is recognized by ScaA cohesins. On the other hand, ScaC-Doc was shown to interact specifically with the recombinant cohesin domain from ScaA, and the ScaA-Coh probe was shown to interact with a native 29-kDa protein spot identified as ScaC by matrix-assisted laser desorption ionization-time of flight mass spectrometry. These results suggest that ScaC plays the role of an adaptor scaffoldin that is bound to ScaA via the ScaC dockerin module, which, via the distinctive ScaC cohesin, expands the range of proteins that can bind to the ScaA-based enzyme complex. (+info)Interaction between a type-II dockerin domain and a type-II cohesin domain from Clostridium thermocellum cellulosome. (2/63)
The interaction between the type-II dockerin domain of the scaffoldin protein CipA and the type-II cohesin domain of the outer layer protein SdbA is the fundamental mechanism for anchoring the cellulosome to the cell surface of Clostridium thermocellum. We constructed and purified a dockerin polypeptide and a cohesin polypeptide, and determined affinity constants of the interaction between them by the surface plasmon resonance method. The dissociation constant (K(D)) value was 1.8 x 10(-9) M, which is a little larger than that for the combination of a type-I dockerin and a type-I cohesin. (+info)A novel Acetivibrio cellulolyticus anchoring scaffoldin that bears divergent cohesins. (3/63)
Sequencing of a cellulosome-integrating gene cluster in Acetivibrio cellulolyticus was completed. The cluster contains four tandem scaffoldin genes (scaA, scaB, scaC, and scaD) bounded upstream and downstream, respectively, by a presumed cellobiose phosphorylase and a nucleotide methylase. The sequences and properties of scaA, scaB, and scaC were reported previously, and those of scaD are reported here. The scaD gene encodes an 852-residue polypeptide that includes a signal peptide, three cohesins, and a C-terminal S-layer homology (SLH) module. The calculated molecular weight of the mature ScaD is 88,960; a 67-residue linker segment separates cohesins 1 and 2, and two approximately 30-residue linkers separate cohesin 2 from 3 and cohesin 3 from the SLH module. The presence of an SLH module in ScaD indicates its role as an anchoring protein. The first two ScaD cohesins can be classified as type II, similar to the four cohesins of ScaB. Surprisingly, the third ScaD cohesin belongs to the type I cohesins, like the seven ScaA cohesins. ScaD is the first scaffoldin to be described that contains divergent types of cohesins as integral parts of the polypeptide chain. The recognition properties among selected recombinant cohesins and dockerins from the different scaffoldins of the gene cluster were investigated by affinity blotting. The results indicated that the divergent types of ScaD cohesins also differ in their preference of dockerins. ScaD thus plays a dual role, both as a primary scaffoldin, capable of direct incorporation of a single dockerin-borne enzyme, and as a secondary scaffoldin that anchors the major primary scaffoldin, ScaA and its complement of enzymes to the cell surface. (+info)Hydrophilic domains of scaffolding protein CbpA promote glycosyl hydrolase activity and localization of cellulosomes to the cell surface of Clostridium cellulovorans. (4/63)
CbpA, the scaffolding protein of Clostridium cellulovorans cellulosomes, possesses one family 3 cellulose binding domain, nine cohesin domains, and four hydrophilic domains (HLDs). Among the three types of domains, the function of the HLDs is still unknown. We proposed previously that the HLDs of CbpA play a role in attaching the cellulosome to the cell surface, since they showed some homology to the surface layer homology domains of EngE. Several recombinant proteins with HLDs (rHLDs) and recombinant EngE (rEngE) were examined to determine their binding to the C. cellulovorans cell wall fraction. Tandemly linked rHLDs showed higher affinity for the cell wall than individual rHLDs showed. EngE was shown to have a higher affinity for cell walls than rHLDs have. C. cellulovorans native cellulosomes were found to have higher affinity for cell walls than rHLDs have. When immunoblot analysis was carried out with the native cellulosome fraction bound to cell wall fragments, the presence of EngE was also confirmed, suggesting that the mechanism anchoring CbpA to the C. cellulovorans cell surface was mediated through EngE and that the HLDs play a secondary role in the attachment of the cellulosome to the cell surface. During a study of the role of HLDs on cellulose degradation, the mini-cellulosome complexes with HLDs degraded cellulose more efficiently than complexes without HLDs degraded cellulose. The rHLDs also showed binding affinity for crystalline cellulose and carboxymethyl cellulose. These results suggest that the CbpA HLDs play a major role and a minor role in C. cellulovorans cellulosomes. The primary role increases cellulose degradation activity by binding the cellulosome complex to the cellulose substrate; secondarily, HLDs aid the binding of the CbpA/cellulosome to the C. cellulovorans cell surface. (+info)Towards designer cellulosomes in Clostridia: mannanase enrichment of the cellulosomes produced by Clostridium cellulolyticum. (5/63)
The man5K gene of Clostridium cellulolyticum was cloned and overexpressed in Escherichia coli. This gene encodes a 424-amino-acid preprotein composed of an N-terminal leader peptide, followed by a dockerin module and a C-terminal catalytic module belonging to family 5 of the glycosyl hydrolases. Mature Man5K displays 62% identity with ManA from Clostridium cellulovorans. Two forms of the protein were purified from E. coli; one form corresponds to the full-length enzyme (45 kDa), and a truncated form (39 kDa) lacks the N-terminal dockerin module. Both forms exhibit the same typical family 5 mannanase substrate preference; they are very active with the galactomannan locust bean gum, and the more galacto-substituted guar gum molecules are degraded less. The truncated form, however, displays fourfold-higher activity with galactomannans than the full-length enzyme. Man5K was successfully overproduced in C. cellulolyticum by using expression vectors. The trans-produced protein was found to be incorporated into the cellulosomes and became one of the major enzymatic components. Modified cellulosomes displayed 20-fold-higher specific activities than control fractions on galactomannan substrates, whereas the specific activity on crystalline cellulose was reduced by 20%. This work clearly showed that the composition of the cellulosomes is obviously regulated by the relative amounts of the enzymes produced and that this composition can be engineered in clostridia by structural gene cloning. (+info)Structural insights into the mechanism of formation of cellulosomes probed by small angle X-ray scattering. (6/63)
Exploring the mechanism by which the multiprotein complexes of cellulolytic organisms, the cellulosomes, attain their exceptional synergy is a challenge for biologists. We have studied the solution structures of the Clostridium cellulolyticum cellulosomal enzyme Cel48F in the free and complexed states with cohesins from Clostridium thermocellum and Clostridium cellulolyticum by small angle x-ray scattering in order to investigate the conformational events likely to occur upon complexation. The solution structure of the free cellulase indicates that the dockerin module is folded, whereas the linker connecting the catalytic module to the dockerin is extended and flexible. Remarkably, the docking of the different cohesins onto Cel48F leads to a pleating of the linker. The global structure determined here allowed modeling of the atomic structure of the C. cellulolyticum dockerin-cohesin interface, highlighting the local differences between both organisms responsible for the species specificity. (+info)Interactions between immunoglobulin-like and catalytic modules in Clostridium thermocellum cellulosomal cellobiohydrolase CbhA. (7/63)
Cellobiohydrolase CbhA from Clostridium thermocellum cellulosome is a multi-modular protein composed starting from the N-terminus of a carbohydrate-binding module (CBM) of family 4, an immunoglobulin(Ig)-like module, a catalytic module of family 9 glycoside hydrolases (GH9), X1(1) and X1(2) modules, a CBM of family 3 and a dockerin module. Deletion of the Ig-like module from the Ig-GH9 construct results in complete inactivation of the GH9 module. The crystal structure of the Ig-GH9 module pair reveals the existence of an extensive module interface composed of over 40 amino acid residues of both modules and maintained through a large number of hydrophilic and hydrophobic interactions. To investigate the importance of these interactions between the two modules, we compared the secondary and tertiary structures and thermostabilities of the individual Ig-like and GH9 modules and the Ig-GH9 module pair using both circular dichroism (CD) spectroscopy and differential scanning calorimetry (DSC). Thr230, Asp262 and Asp264 of the Ig-like module are located in the module interface of the Ig-GH9 module pair and are suggested to be important in 'communication' between the modules. These residues were mutated to alanyl residues. The structure, stability and catalytic properties of the native Ig-GH9 and its D264A and T230A/D262A mutants were compared. The results indicate that despite being able to fold relatively independently, the Ig-like and GH9 modules interact and these interactions affect the final fold and stability of each module. Mutations of one or two amino acid residues lead to destabilization and change of the mechanism of thermal unfolding of the polypeptides. The enzymatic properties of native Ig-GH9, D264A and T230A/D262A mutants are similar. The results indicate that inactivation of the GH9 module occurs as a result of multiple structural disturbances finally affecting the topology of the catalytic center. (+info)Action of designer cellulosomes on homogeneous versus complex substrates: controlled incorporation of three distinct enzymes into a defined trifunctional scaffoldin. (8/63)
In recent work, we reported the self-assembly of a comprehensive set of defined "bifunctional" chimeric cellulosomes. Each complex contained the following: (i) a chimeric scaffoldin possessing a cellulose-binding module and two cohesins of divergent specificity and (ii) two cellulases, each bearing a dockerin complementary to one of the divergent cohesins. This approach allowed the controlled integration of desired enzymes into a multiprotein complex of predetermined stoichiometry and topology. The observed enhanced synergy on recalcitrant substrates by the bifunctional designer cellulosomes was ascribed to two major factors: substrate targeting and proximity of the two catalytic components. In the present work, the capacity of the previously described chimeric cellulosomes was amplified by developing a third divergent cohesin-dockerin device. The resultant trifunctional designer cellulosomes were assayed on homogeneous and complex substrates (microcrystalline cellulose and straw, respectively) and found to be considerably more active than the corresponding free enzyme or bifunctional systems. The results indicate that the synergy between two prominent cellulosomal enzymes (from the family-48 and -9 glycoside hydrolases) plays a crucial role during the degradation of cellulose by cellulosomes and that one dominant family-48 processive endoglucanase per complex is sufficient to achieve optimal levels of synergistic activity. Furthermore cooperation within a cellulosome chimera between cellulases and a hemicellulase from different microorganisms was achieved, leading to a trifunctional complex with enhanced activity on a complex substrate. (+info)Cellulosomes are large, complex enzymatic structures produced by certain anaerobic bacteria that allow them to break down and consume cellulose, a major component of plant biomass. These structures are composed of multiple enzymes that work together in a coordinated manner to degrade cellulose into simpler sugars, which the bacteria can then use as a source of energy and carbon.
The individual enzymes in a cellulosome are non-covalently associated with a central scaffoldin protein, forming a multi-enzyme complex. The scaffoldin protein contains cohesin modules that bind to dockerin modules on the enzyme subunits, creating a highly organized and stable structure.
Cellulosomes have been identified in several species of anaerobic bacteria, including members of the genera Clostridium and Ruminococcus. They are thought to play a key role in the global carbon cycle by breaking down plant material and releasing carbon dioxide back into the atmosphere.
'Clostridium thermocellum' is a type of anaerobic, gram-positive bacterium that is known for its ability to produce cellulases and break down cellulose. It is thermophilic, meaning it grows optimally at higher temperatures, typically between 55-70°C. This organism is of interest in the field of bioenergy because of its potential to convert plant biomass into useful products such as biofuels. However, it's important to note that this bacterium can also produce harmful metabolic byproducts and can be potentially pathogenic to humans.
'Clostridium cellulolyticum' is a species of gram-positive, rod-shaped, anaerobic bacteria found in soil and aquatic environments. It is known for its ability to break down complex carbohydrates such as cellulose and hemicellulose into simple sugars through the process of fermentation. This makes it a potential candidate for biofuel production from plant biomass.
The bacterium produces a range of enzymes that can degrade these polysaccharides, including cellulases and xylanases. These enzymes work together in a complex system to break down the cellulose and hemicellulose into monosaccharides, which can then be fermented by the bacterium to produce various end products such as acetate, ethanol, hydrogen, and carbon dioxide.
'Clostridium cellulolyticum' is also known to produce a number of other enzymes and metabolites that have potential applications in industry, including amylases, proteases, and lipases. However, further research is needed to fully understand the biology and potential uses of this organism.
Cellulase is a type of enzyme that breaks down cellulose, which is a complex carbohydrate and the main structural component of plant cell walls. Cellulases are produced by certain bacteria, fungi, and protozoans, and are used in various industrial applications such as biofuel production, food processing, and textile manufacturing. In the human body, there are no known physiological roles for cellulases, as humans do not produce these enzymes and cannot digest cellulose.
Cellulose is a complex carbohydrate that is the main structural component of the cell walls of green plants, many algae, and some fungi. It is a polysaccharide consisting of long chains of beta-glucose molecules linked together by beta-1,4 glycosidic bonds. Cellulose is insoluble in water and most organic solvents, and it is resistant to digestion by humans and non-ruminant animals due to the lack of cellulase enzymes in their digestive systems. However, ruminants such as cows and sheep can digest cellulose with the help of microbes in their rumen that produce cellulase.
Cellulose has many industrial applications, including the production of paper, textiles, and building materials. It is also used as a source of dietary fiber in human food and animal feed. Cellulose-based materials are being explored for use in biomedical applications such as tissue engineering and drug delivery due to their biocompatibility and mechanical properties.
Cellulases are a group of enzymes that break down cellulose, which is a complex carbohydrate and the main structural component of plant cell walls. These enzymes are produced by various organisms, including bacteria, fungi, and protozoa. They play an important role in the natural decomposition process and have various industrial applications, such as in the production of biofuels, paper, and textiles.
Cellulases work by hydrolyzing the beta-1,4 glycosidic bonds between the glucose molecules that make up cellulose, breaking it down into simpler sugars like glucose. This process is known as saccharification. The specific type of cellulase enzyme determines where on the cellulose molecule it will cleave the bond.
There are three main types of cellulases: endoglucanases, exoglucanases, and beta-glucosidases. Endoglucanases randomly attack internal bonds in the amorphous regions of cellulose, creating new chain ends for exoglucanases to act on. Exoglucanases (also known as cellobiohydrolases) cleave cellobiose units from the ends of the cellulose chains, releasing cellobiose or glucose. Beta-glucosidases convert cellobiose into two molecules of glucose, which can then be further metabolized by the organism.
In summary, cellulases are a group of enzymes that break down cellulose into simpler sugars through hydrolysis. They have various industrial applications and play an essential role in natural decomposition processes.
'Clostridium' is a genus of gram-positive, rod-shaped bacteria that are widely distributed in nature, including in soil, water, and the gastrointestinal tracts of animals and humans. Many species of Clostridium are anaerobic, meaning they can grow and reproduce in environments with little or no oxygen. Some species of Clostridium are capable of producing toxins that can cause serious and sometimes life-threatening illnesses in humans and animals.
Some notable species of Clostridium include:
* Clostridium tetani, which causes tetanus (also known as lockjaw)
* Clostridium botulinum, which produces botulinum toxin, the most potent neurotoxin known and the cause of botulism
* Clostridium difficile, which can cause severe diarrhea and colitis, particularly in people who have recently taken antibiotics
* Clostridium perfringens, which can cause food poisoning and gas gangrene.
It is important to note that not all species of Clostridium are harmful, and some are even beneficial, such as those used in the production of certain fermented foods like sauerkraut and natto. However, due to their ability to produce toxins and cause illness, it is important to handle and dispose of materials contaminated with Clostridium species carefully, especially in healthcare settings.
'Clostridium cellulovorans' is a species of gram-positive, rod-shaped, anaerobic bacteria that is commonly found in soil and aquatic environments. It is known for its ability to break down complex carbohydrates, such as cellulose and xylan, into simpler sugars, which it then ferments to produce various end products, including acetate, ethanol, hydrogen, and carbon dioxide.
The bacterium is of interest in the field of bioenergy, as its ability to efficiently convert plant biomass into useful chemicals has potential applications in the production of biofuels and other bioproducts. Additionally, 'C. cellulovorans' has been studied for its potential use in bioremediation, as it is capable of degrading a variety of pollutants, including polycyclic aromatic hydrocarbons (PAHs) and pesticides.
It is important to note that while 'C. cellulovorans' is generally considered to be a non-pathogenic bacterium, it can cause infections in individuals with compromised immune systems or underlying medical conditions. As with any potential pathogen, appropriate precautions should be taken when handling this organism in the laboratory setting.
Endo-1,4-beta Xylanases are a type of enzyme that catalyze the endohydrolysis of 1,4-beta-D-xylosidic linkages in xylans, which are complex polysaccharides made up of beta-1,4-linked xylose residues. Xylan is a major hemicellulose component found in the cell walls of plants, and endo-1,4-beta Xylanases play an important role in the breakdown and digestion of plant material by various organisms, including bacteria, fungi, and animals. These enzymes are widely used in industrial applications, such as biofuel production, food processing, and pulp and paper manufacturing, to break down xylans and improve the efficiency of various processes.
"Piromyces" is not a medical term, but rather it refers to a genus of anamorphic fungi belonging to the family Neocallimastigaceae. These fungi are commonly found in the digestive tracts of various animals, including ruminants and some non-ruminant herbivores, where they play a crucial role in breaking down complex plant material through anaerobic digestion. They are not associated with any human or animal diseases.
Cellobiose is a disaccharide made up of two molecules of glucose joined by a β-1,4-glycosidic bond. It is formed when cellulose or beta-glucans are hydrolyzed, and it can be further broken down into its component glucose molecules by the action of the enzyme beta-glucosidase. Cellobiose has a sweet taste, but it is not as sweet as sucrose (table sugar). It is used in some industrial processes and may have potential applications in the food industry.
Xylans are a type of complex carbohydrate, specifically a hemicellulose, that are found in the cell walls of many plants. They are made up of a backbone of beta-1,4-linked xylose sugar molecules and can be substituted with various side groups such as arabinose, glucuronic acid, and acetyl groups. Xylans are indigestible by humans, but they can be broken down by certain microorganisms in the gut through a process called fermentation, which can produce short-chain fatty acids that have beneficial effects on health.
Xylosidases are a group of enzymes that catalyze the hydrolysis of xylosides, which are glycosides with a xylose sugar. Specifically, they cleave the terminal β-1,4-linked D-xylopyranoside residues from various substrates such as xylooligosaccharides and xylan. These enzymes play an important role in the breakdown and metabolism of plant-derived polysaccharides, particularly hemicelluloses, which are a major component of plant biomass. Xylosidases have potential applications in various industrial processes, including biofuel production and animal feed manufacturing.
Metabolic engineering is a branch of biotechnology that involves the modification and manipulation of metabolic pathways in organisms to enhance their production of specific metabolites or to alter their flow of energy and carbon. This field combines principles from genetics, molecular biology, biochemistry, and chemical engineering to design and construct novel metabolic pathways or modify existing ones with the goal of optimizing the production of valuable compounds or improving the properties of organisms for various applications.
Examples of metabolic engineering include the modification of microorganisms to produce biofuels, pharmaceuticals, or industrial chemicals; the enhancement of crop yields and nutritional value in agriculture; and the development of novel bioremediation strategies for environmental pollution control. The ultimate goal of metabolic engineering is to create organisms that can efficiently and sustainably produce valuable products while minimizing waste and reducing the impact on the environment.
Actinomycetales is an order of Gram-positive bacteria that are characterized by their filamentous morphology and branching appearance, resembling fungi. These bacteria are often found in soil and water, and some species can cause diseases in humans and animals. The name "Actinomycetales" comes from the Greek words "actis," meaning ray or beam, and "mykes," meaning fungus.
The order Actinomycetales includes several families of medical importance, such as Mycobacteriaceae (which contains the tuberculosis-causing Mycobacterium tuberculosis), Corynebacteriaceae (which contains the diphtheria-causing Corynebacterium diphtheriae), and Actinomycetaceae (which contains the actinomycosis-causing Actinomyces israelii).
Actinomycetales are known for their complex cell walls, which contain a unique type of lipid called mycolic acid. This feature makes them resistant to many antibiotics and contributes to their ability to cause chronic infections. They can also form resistant structures called spores, which allow them to survive in harsh environments and contribute to their ability to cause disease.
Overall, Actinomycetales are important both as beneficial soil organisms and as potential pathogens that can cause serious diseases in humans and animals.
Cellulose 1,4-beta-Cellobiosidase is an enzyme that catalyzes the hydrolysis of cellulose, a complex carbohydrate and the main structural component of plant cell walls, into simpler sugars. Specifically, this enzyme breaks down cellulose by cleaving the 1,4-beta-glycosidic bonds between the cellobiose units that make up the cellulose polymer, releasing individual cellobiose molecules (disaccharides consisting of two glucose molecules). This enzyme is also known as cellobiohydrolase or beta-1,4-D-glucan cellobiohydrolase. It plays a crucial role in the natural breakdown of plant material and is widely used in various industrial applications, such as biofuel production and pulp and paper manufacturing.
I'm sorry for any confusion, but "Lignin" is not a medical term. It is a term used in the field of biology and chemistry, particularly in botany and wood science. Lignin is a complex organic polymer that binds cellulose fibers together, providing strength and rigidity to the cell walls of plants. It is a major component of wood and bark.
If you have any medical terms you would like defined or any other questions, please let me know!
Multienzyme complexes are specialized protein structures that consist of multiple enzymes closely associated or bound together, often with other cofactors and regulatory subunits. These complexes facilitate the sequential transfer of substrates along a series of enzymatic reactions, also known as a metabolic pathway. By keeping the enzymes in close proximity, multienzyme complexes enhance reaction efficiency, improve substrate specificity, and maintain proper stoichiometry between different enzymes involved in the pathway. Examples of multienzyme complexes include the pyruvate dehydrogenase complex, the citrate synthase complex, and the fatty acid synthetase complex.
"Triticum" is the genus name for a group of cereal grains that includes common wheat (T. aestivum), durum wheat (T. durum), and spelt (T. spelta). These grains are important sources of food for humans, providing carbohydrates, proteins, and various nutrients. They are used to make a variety of foods such as bread, pasta, and breakfast cereals. Triticum species are also known as "wheat" in layman's terms.
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.
Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).
Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.
Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.
An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.
Polysaccharides are complex carbohydrates consisting of long chains of monosaccharide units (simple sugars) bonded together by glycosidic linkages. They can be classified based on the type of monosaccharides and the nature of the bonds that connect them.
Polysaccharides have various functions in living organisms. For example, starch and glycogen serve as energy storage molecules in plants and animals, respectively. Cellulose provides structural support in plants, while chitin is a key component of fungal cell walls and arthropod exoskeletons.
Some polysaccharides also have important roles in the human body, such as being part of the extracellular matrix (e.g., hyaluronic acid) or acting as blood group antigens (e.g., ABO blood group substances).
Glucans are polysaccharides (complex carbohydrates) that are made up of long chains of glucose molecules. They can be found in the cell walls of certain plants, fungi, and bacteria. In medicine, beta-glucans derived from yeast or mushrooms have been studied for their potential immune-enhancing effects. However, more research is needed to fully understand their role and effectiveness in human health.
Bacterial polysaccharides are complex carbohydrates that consist of long chains of sugar molecules (monosaccharides) linked together by glycosidic bonds. They are produced and used by bacteria for various purposes such as:
1. Structural components: Bacterial polysaccharides, such as peptidoglycan and lipopolysaccharide (LPS), play a crucial role in maintaining the structural integrity of bacterial cells. Peptidoglycan is a major component of the bacterial cell wall, while LPS forms the outer layer of the outer membrane in gram-negative bacteria.
2. Nutrient storage: Some bacteria synthesize and store polysaccharides as an energy reserve, similar to how plants store starch. These polysaccharides can be broken down and utilized by the bacterium when needed.
3. Virulence factors: Bacterial polysaccharides can also function as virulence factors, contributing to the pathogenesis of bacterial infections. For example, certain bacteria produce capsular polysaccharides (CPS) that surround and protect the bacterial cells from host immune defenses, allowing them to evade phagocytosis and persist within the host.
4. Adhesins: Some polysaccharides act as adhesins, facilitating the attachment of bacteria to surfaces or host cells. This is important for biofilm formation, which helps bacteria resist environmental stresses and antibiotic treatments.
5. Antigenic properties: Bacterial polysaccharides can be highly antigenic, eliciting an immune response in the host. The antigenicity of these molecules can vary between different bacterial species or even strains within a species, making them useful as targets for vaccines and diagnostic tests.
In summary, bacterial polysaccharides are complex carbohydrates that serve various functions in bacteria, including structural support, nutrient storage, virulence factor production, adhesion, and antigenicity.
Cellulase
Cellulosome
Dockerin
Cytophaga hutchinsonii
Anaeromyces robustus
Michelle O'Malley
Harry J. Gilbert
Serpin
Edward A. Bayer
Fibrobacter succinogenes
List of MeSH codes (A11)
Mini-cellulosomes & Other Enzymes
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Complexes4
- Cellulosomes are extracellular complexes consisting of multiple enzymes, which are associated with the cell's surface. (phys.org)
- Cellulosomes exist as extracellular complexes that are either attached to the cell wall of bacteria or free in solution, where the insoluble substrate can be broken down into soluble products and taken up by the cell. (cazypedia.org)
- Cellulosomes are naturally occurring elaborate enzyme complexes found in many anaerobic microorganisms that can efficiently hydrolyze cellulose based on the high level of enzyme-substrate synergy [ 9 ]. (biomedcentral.com)
- The degradative enzymes this organism produces are typically exoenzymes that are collected and organized into large surface complexes termed cellulosomes. (up.ac.za)
Scaffolds1
- however, some bacteria use large enzymatic assemblies called cellulosomes, which recruit complementary enzymes to protein scaffolds. (rcsb.org)
Enzymes1
- The GRC meeting on plant cell wall degradation (Cellulosomes, cellulases and other plant cell wall degrading enzymes) in 2013 was extraordinarily successful and has really reinvigorated the field. (megazyme.com)
Bacteria2
- Genetically engineered bacteria might have cellulosomes that could break down waste paper quickly and turn it into fuel. (weizmann.ac.il)
- Early on [ 8 ] it became clear that cellulosomes were not restricted to C. thermocellum , but were present in other cellulolytic bacteria. (cazypedia.org)
Large1
- Cellulosomes were first observed by Bayer and Lamed and their colleagues as large protuberances on the surface of C. The store-house consciousness accumulates the karmic causes the potential energy for the mental and physical manifestation of an individual, thus explaining how rebirth senior online dating service without pay and karma occurs. (alseides-villas.gr)
Enzymes2
- optimised feedstocks (Willow and Miscanthus) from P1 for biobutanol production, - the potential of enzymes identified by P2 & P6 for incorporation into designer cellulosomes, - a sub-set of barley genotypes showing improved saccharification from P3 will be evaluated for biobutanol production, - optimised wheat feedstocks from P4 for biobutanol production. (ukri.org)
- its C-terminus that anchors the cellulosome complex to cell wall associated proteins.25 Other species of anaerobic bacteria also display cellulosomes, which can adopt more elaborate structures that contain as many as 96 enzymes.24 Open in a separate window Number?3. (insulin-receptor.info)
Cellulosome1
- The prototypical CipA cellulosome and methods used to recombinantly display miniaturized cellulosomes (minicellulosomes). (insulin-receptor.info)
Designer1
- Dr. Ed Bayer, Weizmann Institute of Sciences (PLB - Ding) Title: Designer cellulosomes: Why play with nature? (msu.edu)
Research2
- Research article on spore coat CotH kinases from the cellulosomes! (anaerobicfungi.org)
- During his scientific career, he has pioneered two separate areas of research: avidin-biotin technology and the field of cellulosomes with Prof. Raffi Lamed of Tel Aviv University. (cazypedia.org)