An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC 1.18.6.1.
A non-heme iron-sulfur protein isolated from Clostridium pasteurianum and other bacteria. It is a component of NITROGENASE, which is active in nitrogen fixation, and consists of two subunits with molecular weights of 59.5 kDa and 50.7 kDa, respectively.
The process in certain BACTERIA; FUNGI; and CYANOBACTERIA converting free atmospheric NITROGEN to biologically usable forms of nitrogen, such as AMMONIA; NITRATES; and amino compounds.
A genus of gram-negative, aerobic bacteria found in soil and water. Its organisms occur singly, in pairs or irregular clumps, and sometimes in chains of varying lengths.
A species of gram-negative, aerobic bacteria first isolated from soil in Vineland, New Jersey. Ammonium and nitrate are used as nitrogen sources by this bacterium. It is distinguished from other members of its genus by the ability to use rhamnose as a carbon source. (From Bergey's Manual of Determinative Bacteriology, 9th ed)
A metallic element with the atomic symbol Mo, atomic number 42, and atomic weight 95.94. It is an essential trace element, being a component of the enzymes xanthine oxidase, aldehyde oxidase, and nitrate reductase. (From Dorland, 27th ed)
A non-heme iron-sulfur protein isolated from Clostridium pasteurianum and other bacteria. It is a component of NITROGENASE along with molybdoferredoxin and is active in nitrogen fixation.
Gram-negative, non-motile, capsulated, gas-producing rods found widely in nature and associated with urinary and respiratory infections in humans.
Vibrio- to spiral-shaped phototrophic bacteria found in stagnant water and mud exposed to light.
Iron-containing proteins that transfer electrons, usually at a low potential, to flavoproteins; the iron is not present as in heme. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)
An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.
Dithionite. The dithionous acid ion and its salts.
Non-pathogenic ovoid to rod-shaped bacteria that are widely distributed and found in fresh water as well as marine and hypersaline habitats.
The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.
Organic compounds that are acyclic and contain three acid groups. A member of this class is citric acid which is the first product formed by reaction of pyruvate and oxaloacetate. (From Lehninger, Principles of Biochemistry, 1982, p443)
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.
A species of motile, free-living, gram-negative bacteria that occur in the soil. They are aerobic or microaerophilic and are sometimes capable of nitrogen fixation.
Proteins that have one or more tightly bound metal ions forming part of their structure. (Dorland, 28th ed)
A low-molecular-weight (16,000) iron-free flavoprotein containing one molecule of flavin mononucleotide (FMN) and isolated from bacteria grown on an iron-deficient medium. It can replace ferredoxin in all the electron-transfer functions in which the latter is known to serve in bacterial cells.
A metallic element with the atomic symbol V, atomic number 23, and atomic weight 50.94. It is used in the manufacture of vanadium steel. Prolonged exposure can lead to chronic intoxication caused by absorption usually via the lungs.
Argon. A noble gas with the atomic symbol Ar, atomic number 18, and atomic weight 39.948. It is used in fluorescent tubes and wherever an inert atmosphere is desired and nitrogen cannot be used.
The functional hereditary units of BACTERIA.
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).
Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2.
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.
A genus of gram-negative, rod-shaped, phototrophic bacteria found in aquatic environments. Internal photosynthetic membranes are present as lamellae underlying the cytoplasmic membrane.
Proteins found in any species of bacterium.
A genus in the family ACETOBACTERACEAE comprised of acetate-oxidizing bacteria.
A genus of motile or nonmotile gram-positive bacteria of the family Clostridiaceae. Many species have been identified with some being pathogenic. They occur in water, soil, and in the intestinal tract of humans and lower animals.
Tungsten. A metallic element with the atomic symbol W, atomic number 74, and atomic weight 183.85. It is used in many manufacturing applications, including increasing the hardness, toughness, and tensile strength of steel; manufacture of filaments for incandescent light bulbs; and in contact points for automotive and electrical apparatus.
A genus of gram-negative, aerobic, rod-shaped bacteria that activate PLANT ROOT NODULATION in leguminous plants. Members of this genus are nitrogen-fixing and common soil inhabitants.
A family of signal transducing adaptor proteins that control the METABOLISM of NITROGEN. They are primarily found in prokaryotes.
Proteins, usually acting in oxidation-reduction reactions, containing iron but no porphyrin groups. (Lehninger, Principles of Biochemistry, 1993, pG-10)
A genus of CYANOBACTERIA consisting of trichomes that are untapered with conspicuous constrictions at cross-walls. A firm individual sheath is absent, but a soft covering is often present. Many species are known worldwide as major components of freshwater PLANKTON and also of many saline lakes. The species ANABAENA FLOS-AQUAE is responsible for acute poisonings of various animals.
A genus of gram-negative, facultatively anaerobic bacteria including species which are often associated with grasses (POACEAE) and which fix nitrogen as well as species which anaerobically degrade toluene and other mono-aromatic hydrocarbons.
A species of ANABAENA that can form SPORES called akinetes.
A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.
An acidifying agent that has expectorant and diuretic effects. Also used in etching and batteries and as a flux in electroplating.
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)
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
An enzyme that catalyzes the conversion of ATP, L-glutamate, and NH3 to ADP, orthophosphate, and L-glutamine. It also acts more slowly on 4-methylene-L-glutamate. (From Enzyme Nomenclature, 1992) EC 6.3.1.2.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
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.
The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
A hemoglobin-like oxygen-binding hemeprotein present in the nitrogen-fixing root nodules of leguminous plants. The red pigment has a molecular weight approximately 1/4 that of hemoglobin and has been suggested to act as an oxido-reduction catalyst in symbiotic nitrogen fixation.
The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis.
The relationship between two different species of organisms that are interdependent; each gains benefits from the other or a relationship between different species where both of the organisms in question benefit from the presence of the other.
A form-genus of unicellular coccoid to rod-shaped CYANOBACTERIA, in the order Chroococcales. Three different clusters of strains from diverse habitats are included.
The rate dynamics in chemical or physical systems.
Organic and inorganic compounds that contain iron as an integral part of the molecule.
Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
A family of gram-negative aerobic bacteria consisting of ellipsoidal to rod-shaped cells that occur singly, in pairs, or in chains.
The absence of light.
Genus of BACTERIA in the family Frankiaceae. They are nitrogen-fixing root-nodule symbionts of many species of woody dicotyledonous plants.
Used as an electron carrier in place of the flavine enzyme of Warburg in the hexosemonophosphate system and also in the preparation of SUCCINIC DEHYDROGENASE.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Small molecules that are required for the catalytic function of ENZYMES. Many VITAMINS are coenzymes.
An enzyme found in bacteria. It catalyzes the reduction of FERREDOXIN and other substances in the presence of molecular hydrogen and is involved in the electron transport of bacterial photosynthesis.
Enzymes that transfer the ADP-RIBOSE group of NAD or NADP to proteins or other small molecules. Transfer of ADP-ribose to water (i.e., hydrolysis) is catalyzed by the NADASES. The mono(ADP-ribose)transferases transfer a single ADP-ribose. POLY(ADP-RIBOSE) POLYMERASES transfer multiple units of ADP-ribose to protein targets, building POLY ADENOSINE DIPHOSPHATE RIBOSE in linear or branched chains.
An amino acid that inhibits phosphate-activated glutaminase and interferes with glutamine metabolism. It is an antineoplastic antibiotic produced by an unidentified species of Streptomyces from Peruvian soil. (From Merck Index, 11th ed)

Correlation of activity regulation and substrate recognition of the ADP-ribosyltransferase that regulates nitrogenase activity in Rhodospirillum rubrum. (1/904)

In Rhodospirillum rubrum, nitrogenase activity is regulated posttranslationally through the ADP-ribosylation of dinitrogenase reductase by dinitrogenase reductase ADP-ribosyltransferase (DRAT). Several DRAT variants that are altered both in the posttranslational regulation of DRAT activity and in the ability to recognize variants of dinitrogenase reductase have been found. This correlation suggests that these two properties are biochemically connected.  (+info)

The presence of ADP-ribosylated Fe protein of nitrogenase in Rhodobacter capsulatus is correlated with cellular nitrogen status. (2/904)

The photosynthetic bacterium Rhodobacter capsulatus has been shown to regulate its nitrogenase by covalent modification via the reversible ADP-ribosylation of Fe protein in response to darkness or the addition of external NH4+. Here we demonstrate the presence of ADP-ribosylated Fe protein under a variety of steady-state growth conditions. We examined the modification of Fe protein and nitrogenase activity under three different growth conditions that establish different levels of cellular nitrogen: batch growth with limiting NH4+, where the nitrogen status is externally controlled; batch growth on relatively poor nitrogen sources, where the nitrogen status is internally controlled by assimilatory processes; and continuous culture. When cultures were grown to stationary phase with different limiting concentrations of NH4+, the ADP-ribosylation state of Fe protein was found to correlate with cellular nitrogen status. Additionally, actively growing cultures (grown with N2 or glutamate), which had an intermediate cellular nitrogen status, contained a portion of their Fe protein in the modified state. The correlation between cellular nitrogen status and ADP-ribosylation state was corroborated with continuous cultures grown under various degrees of nitrogen limitation. These results show that in R. capsulatus the modification system that ADP-ribosylates nitrogenase in the short term in response to abrupt changes in the environment is also capable of modifying nitrogenase in accordance with long-term cellular conditions.  (+info)

Classes of Anabaena variabilis mutants with oxygen-sensitive nitrogenase activity. (3/904)

Mutants of Anabaena variabilis deficient in the envelope glycolipids of heterocysts have no or very low nitrogenase activity when assayed aerobically. Revertants capable of aerobic growth on N2 have increased quantities of these glycolipids. Among mutants which require fixed nitrogen for growth in air and which have a normal complement of glycolipids, one expresses high nitrogenase activity at low oxygen tension. Three others show high nitrogenase activity only in the presence of dithionite and are therefore impaired in electron transfer.  (+info)

Azorhizobium caulinodans PII and GlnK proteins control nitrogen fixation and ammonia assimilation. (4/904)

We herein report that Azorhizobium caulinodans PII and GlnK are not necessary for glutamine synthetase (GS) adenylylation whereas both proteins are required for complete GS deadenylylation. The disruption of both glnB and glnK resulted in a high level of GS adenylylation under the condition of nitrogen fixation, leading to ammonium excretion in the free-living state. PII and GlnK also controlled nif gene expression because NifA activated nifH transcription and nitrogenase activity was derepressed in glnB glnK double mutants, but not in wild-type bacteria, grown in the presence of ammonia.  (+info)

MgATP-independent hydrogen evolution catalysed by nitrogenase: an explanation for the missing electron(s) in the MgADP-AlF4 transition-state complex. (5/904)

When the MoFe (Kp1) and Fe (Kp2) component proteins of Klebsiella pneumoniae nitrogenase are incubated with MgADP and AlF4(-) in the presence of dithionite as a reducing agent, a stable putative transition-state complex is produced [Yousafzai and Eady (1997) Biochem. J. 326, 637-640]. Surprisingly, the EPR signal associated with reduced Kp2 is not detectable, but Kp1 retains the S=3/2 EPR signal arising from the dithionite reduced state of the MoFe cofactor centre of the protein. This is consistent with the [Fe4S4] centre of the Fe protein in the complex being oxidized, and similar observations have been made with the complex of Azotobacter vinelandii [Spee, Arendsen, Wassink, Marritt, Hagen and Haaker (1998) FEBS Lett. 432, 55-58]. No satisfactory explanation for the fate of the electrons lost by Kp2 has been forthcoming. However, we report here that during the preparation of the MgADP-AlF4 K. pneumoniae complex under argon, H2 was evolved in amounts corresponding to one half of the FeMoco content of the Kp1 (FeMoco is the likely catalytic site of nitrogenase with a composition Mo:Fe7:S9:homocitrate). This is surprising, since activity is observed during incubation in the absence of MgATP, normally regarded as being essential for nitrogenase function, and in the presence of MgADP, a strong competitive inhibitor of nitrogenase. The formation of H2 by nitrogenase in the absence of AlF4(-) was also observed in reaction mixtures containing MgADP but not MgATP. The reaction showed saturation kinetics when Kp1 was titrated with increasing amounts of Kp2 and, at saturation, the amount of H2 formed was stoichiometric with the FeMoco content of Kp1. The dependence of the rate of formation of H2 on [MgADP] was inconsistent with the activity arising from MgATP contamination. We conclude that MgATP is not obligatory for H+ reduction by nitrogenase since MgADP supports a very low rate of hydrogen evolution.  (+info)

Organization and expression of nitrogen-fixation genes in the aerobic nitrogen-fixing unicellular cyanobacterium Synechococcus sp. strain RF-1. (6/904)

Sixteen nif and 'nif-associated' genes (expressed only under conditions of nitrogen fixation) in Synechococcus sp. strain RF-1 have been cloned and sequenced. All of the nif and nif-associated genes identified in Synechococcus RF-1 were arranged in a continuous cluster spanning approximately 18 kb and containing seven operons. The nifH operon (nifH-nifD-nifK) has been reported previously. nifB, fdxN, nifS, nifU and nifP were found to be located upstream of the nifH operon. nifB-fdxN-nifS-nifU were expressed as an operon. A nifP-like gene was found to be located just upstream of nifB. nifE, nifN, nifX, nifW and the nif-associated hesA, hesB and 'fdx' were found to be located downstream from nifK. The genes located downstream from nifK are arranged nifE-nifN-nifX-orf-nifW-hesA-hesB-'+ ++fdx' and span approximately 7 kb. The function of the ORF situated between nifX and nifW is not known. However, it was identified as a counterpart of ORF-2 in Anabaena sp. strain PCC 7120 based on the deduced amino acid sequence. Northern hybridization and primer extension analysis indicated that the nif and nif-associated genes are organized in nifE-nifN, nifX-orf, nifW-hesA-hesB and 'fdx'-containing operons, respectively. According to the results of this study and previous reports, the genes are expressed in a rhythmic pattern with peaks during the dark phase when the culture is grown in a 12 h light/12 h dark regimen. The rhythm persisted after the culture was transferred to continuous illumination.  (+info)

Requirement of NifX and other nif proteins for in vitro biosynthesis of the iron-molybdenum cofactor of nitrogenase. (7/904)

The iron-molybdenum cofactor (FeMo-co) of nitrogenase contains molybdenum, iron, sulfur, and homocitrate in a ratio of 1:7:9:1. In vitro synthesis of FeMo-co has been established, and the reaction requires an ATP-regenerating system, dithionite, molybdate, homocitrate, and at least NifB-co (the metabolic product of NifB), NifNE, and dinitrogenase reductase (NifH). The typical in vitro FeMo-co synthesis reaction involves mixing extracts from two different mutant strains of Azotobacter vinelandii defective in the biosynthesis of cofactor or an extract of a mutant strain complemented with the purified missing component. Surprisingly, the in vitro synthesis of FeMo-co with only purified components failed to generate significant FeMo-co, suggesting the requirement for one or more other components. Complementation of these assays with extracts of various mutant strains demonstrated that NifX has a role in synthesis of FeMo-co. In vitro synthesis of FeMo-co with purified components is stimulated approximately threefold by purified NifX. Complementation of these assays with extracts of A. vinelandii DJ42. 48 (DeltanifENX DeltavnfE) results in a 12- to 15-fold stimulation of in vitro FeMo-co synthesis activity. These data also demonstrate that apart from the NifX some other component(s) is required for the cofactor synthesis. The in vitro synthesis of FeMo-co with purified components has allowed the detection, purification, and identification of an additional component(s) required for the synthesis of cofactor.  (+info)

Carbon and ammonia metabolism of Spirillum lipoferum. (8/904)

Intact cells and extracts from Spirillum lipoferum rapidly oxidized malate, succinate, lactate, and pyruvate. Glucose, galactose, fructose, acetate, and citrate did not increase the rate of O2 uptake by cells above the endogenous rate. Cells grown on NH+/4 oxidized the various substrates at about the same rate as did cells grown on N2. Added oxidized nicotinamide adenine dinucleotide generally enhanced O2 uptake by extracts supplied organic acids, whereas oxidized nicotinamide adenine dinucleotide phosphate had little effect. Nitrogenase synthesis repressed by growth of cells in the presence of NH+/4 was derepressed by methionine sulfoximine or methionine sulfone. The total glutamine synthetase activity from N2-grown cells was about eight times that from NH+/4-grown S. lipoferum; the response of glutamate dehydrogenase was the opposite. The total glutamate synthetase activity from N2-grown S. lipoferum was 1.4 to 2.6 times that from NH+/4-grown cells. The levels of poly-beta-hydroxybutyrate and beta-hydroxybutyrate dehydrogenase were elevated in cells grown on N2 as compared with those grown on NH+/4. Cell-free extracts capable of reducing C2H2 have been prepared; both Mg2+ and Mn2+ are required for good activity.  (+info)

SUMMARY: 55FeCI3 labelling and non-denaturing gel electrophoresis were used to study nitrogenase synthesis in Gloeothece sp. CCAP 1430/3. Nitrogenase synthesis was inhibited by addition of NHX but was unaffected by elevated concentrations of O2. Upon transfer of cultures of Gloeothece from light to darkness, there was initially a slight decrease in the rate of synthesis of nitrogenase but after 4-5 h there was an almost complete cessation of synthesis. This delayed effect of darkness on nitrogenase synthesis could not be related to any change in RNA synthesis, in protein synthesis or in the rate of breakdown of storage glucan. In cultures of Gloeothece, mRNA, including nif mRNA, was unstable, having a half-life of about 5 min. The synthesis of nif mRNA did not stop immediately upon transfer of cultures to the dark. If darkness exerts its effect on nitrogenase synthesis by inhibiting the synthesis of nif mRNA, it does so only after a lag of about 4 h.
Nitrogenase is a complex metal-containing enzyme that catalyzes the conversion of nitrogen gas to ammonia. During nitrogenase catalysis the Fe protein and the molybdenum-iron protein associate and dissociate in a manner resulting in the hydrolysis of two molecules of MgATP and the transfer of at least one electron to the MoFe protein. The role of nucleotide binding and hydrolysis in nitrogenase catalysis is one of the most fascinating aspects of nitrogenase function. The Fe protein upon binding to MgATP undergoes a huge conformational change which is important for subsequent steps of nitrogenase reaction mechanism. Therefore structural characterization of the Fe protein bound to MgATP will provide a basis on how MgATP binding promotes the complex formation whereas hydrolysis to MgADP leads to the dissociation of the macromolecular complex structure. Towards these ends we have conducted structural studies on a site-directed variant of the Fe protein which is a close mimic of the MgATP ...
Nitrogenase activity exhibits a dilution effect. Evidence is presented that the reason for the dilution effect is that one of the component proteins of nitrogenase is limiting in preparations of this enzyme. The limiting component appears to be the non-haem-iron-containing protein (also called fraction II, iron protein, azoferredoxin), which is equivalent to the enhancement factor for nitrogenase activity present in extracts of nitrogenaseless mutant 22R1. A mathematical function of specific activity is described that is useful in describing nitrogenase. It takes into account the dilution effect and the exponential nature of the relationship between nitrogenase activity and enzyme protein concentration.. ...
Rhodopseudomonas viridis grows by means of nitrogen fixation under anaerobic, photosynthetic conditions. In batch culture, nitrogenase activity was highest at early-logarithmic phase, lower during mid- to late-logarithmic phase, and nearly zero during stationary phase. Nitrogen-fixing cells were morphologically and ultrastructurally similar to non-nitrogen-fixing cells as determined by electron microscopy. Electron spin resonance (esr) spectroscopy of nitrogen-fixing whole cells yielded g4.26 and g3.66 signals indicating the presence of nitrogenase molybdenum-iron (MoFe) protein. Ammonia switch-off occurred upon addition of 0.2 mM NH(,4)Cl, however, nitrogenase activity did not reappear for nearly four hours. Esr spectroscopy of whole cell multilayers (WCM) of Azotobacter vinelandii and Rhodospirillum rubrum was used to detect structural associations between nitrogenase MoFe protein and cell membrane. Conditions were defined for observing MoFe protein esr signals in whole cell preparations of each
The nitrogenase enzyme, which catalyzes the reduction of N2 gas to NH4+, occurs as three separate isozyme that use Mo, Fe-only, or V. The majority of global nitrogen fixation is attributed to the more efficient canonical Mo-nitrogenase, whereas Fe-only and V-(alternative) nitrogenases are often considered backup enzymes, used when Mo is limiting. Yet, the environmental distribution and diversity of alternative nitrogenases remains largely unknown. We searched for alternative nitrogenase genes in sequenced genomes and used PacBio sequencing to explore the diversity of canonical (nifD) and alternative (anfD and vnfD) nitrogenase amplicons in two coastal environments: the Florida Everglades and Sippewissett Marsh (MA). Genome-based searches identified an additional 25 species and 10 genera not previously known to encode alternative nitrogenases. Alternative nitrogenase amplicons were found in both Sippewissett Marsh and the Florida Everglades and their activity was further confirmed using newly
The first report of successful expression of functional NifH (dinitrogenase reductase) in aerobically grown S. cerevisiae established that mitochondria provide a suitable environment for production of the O2-sensitive nitrogenase proteins (16). The study also showed that activation of mitochondrial-targeted NifH only required additional coexpression of its associated maturase NifM. Thus, endogenous yeast mitochondrial [Fe-S] cluster biosynthetic machinery sufficed to provide NifH with its essential [4Fe-4S] cluster, which is normally provided by NifU and NifS (33). This result suggested that not all nif gene products essential for functional assembly of an active nitrogenase in a model prokaryotic system would necessarily be required for assembly of an active nitrogenase in a particular eukaryotic system. In other words, certain essential prokaryotic components can be replaced by eukaryotic proteins having similar functions. However, as discussed below, the present work reveals that this ...
TY - JOUR. T1 - 57Fe ENDOR spectroscopy and ?electron inventory? analysis of the nitrogenase E4 intermediate suggest the metal-ion core of FeMo-cofactor cycles through only one redox couple. AU - Doan, Peter E.. AU - Telser, Joshua. AU - Barney, Brett M.. AU - Igarashi, Robert Y.. AU - Dean, Dennis R.. AU - Seefeldt, Lance C.. AU - Hoffman, Brian M.. PY - 2011/11/2. Y1 - 2011/11/2. N2 - N2 binds to the active-site metal cluster in the nitrogenase MoFe protein, the FeMo-cofactor ([7Fe-9S-Mo-homocitrate-X]; FeMo-co) only after the MoFe protein has accumulated three or four electrons/protons (E3 or E4 states), with the E4 state being optimally activated. Here we study the FeMo-co 57Fe atoms of E4 trapped with the α-70Val→Ile MoFe protein variant through use of advanced ENDOR methods: ?random-hop? Davies pulsed 35 GHz ENDOR; difference triple resonance; the recently developed Pulse-Endor-SaTuration and REcovery (PESTRE) protocol for determining hyperfine-coupling signs; and Raw-DATA (RD)-PESTRE, ...
Nitrogenase catalyzes the biological reduction of N2 to ammonia (nitrogen fixation). The metalloclusters associated with the nitrogenase components include the [4Fe-4S] cluster of the Fe protein, and the P-cluster [8Fe7S] and FeMo-cofactor [7Fe-9S-Mo-X-homocitrate], both contained within the MoFe protein. These metal-complexes play a vital role in enzyme activity during electron transport and substrate reduction. It is known that the FeMo-cofactor provides the site of substrate reduction, but the exact site of substrate binding remains a topic of intense debate. Some models for the substrate binding location favor the molybdenum atom, while other models favor one or more iron atoms within FeMo-cofactor. We have shown that the a-70 residue of the MoFe protein plays a significant role in defining substrate access to the active site: a-70 approaches one 4Fe-4S face of the FeMo-cofactor. Substitutions at this position alter enzyme specificity for reduction of alternative alkyne substrates. These ...
Little is known about substrate binding and reduction of nitrogenase. EPR spectroscopy is used here to observe intermediate states generated by different substrates. Two different spin states (S=3/2 and S=1/2) were exhibited for each substrate, which may result from different binding of the substrate to the cofactor (side-on or terminal binding) or the difference of the substrate binding to either Fe or Mo of the cofactor. Parallel studies were performed on a variant MoFe protein, alpha-195Gln, which exhibited different signals from the wild-type suggesting that the substituted amino acid maybe necessary to reach some mechanistic states that the wild-type MoFe protein can reach. Electron transfer between the Fe protein and the MoFe protein was investigated to help determine the initial electron transfer pathway in nitrogenase. The altered Fe protein, L127-deletion Fe protein, is permanently in the complex-ready conformation and complexes with the MoFe protein to allow one electron transfer. The MCD
Azotobacter vinelandii is a free-living, obligately aerobic, nitrogen-fixing gamma-proteobacteria. It is found in soils world-wide, with features of nitrogen and energy metabolism relevant to agriculture. In response to carbon starvation it differentiates to form cysts that are impervious to chemical and physical challenge. Studies have been focused on its ability to fix diatmospheric nitrogen under free-living conditions, a process that occurs in the presence of oxygen levels that typically inactivate the nitrogenase enzyme. Unusually it encodes three distinct nitrogenase systems, the molybdenum, vanadium and iron-only nitrogenases, expression of which is differentially regulated by metal availability from the medium. Diazotrophic growth under aerobic conditions is possible because it adjusts oxygen-consumption rates to help maintain low levels of cytoplasmic oxygen, a phenomenon called respiratory protection. It is able to produce alginate, a polymer that further protects the organism from ...
One of the most intriguing aspects of Trichodesmium biology is the simultaneous occurrence of N2 fixation and photosynthesis. Several hypotheses explaining howTrichodesmium might fix N2 aerobically have been proposed. First, it is possible that the properties ofTrichodesmium nitrogenase are unique with respect to their resistance to O2 inactivation. Second, nitrogenase may be transiently modified to protect it from permanent O2deactivation, or it may be continually synthesized to replace protein being inactivated by O2. Third, there may be intracellular O2-consumptive processes that maintain O2 at concentrations compatible with N2 fixation. Finally, N2 fixation and photosynthesis may be spatially segregated in some manner-for instance, either within specific regions in a colony or by cell differentiation within a trichome-such that N2 fixation and photosynthesis are mutually exclusive within individual cells.. Mapping of the Trichodesmium nitrogenase operon and subsequent sequencing of ...
Requires Mg2+. The enzyme is a complex of two components (namely dinitrogen reductase and dinitrogenase). Dinitrogen reductase is a [4Fe-4S] protein, which, in the presence of two molecules of ATP, transfers an electron from ferredoxin to the dinitrogenase component. Dinitrogenase is a molybdenum-iron protein that reduces dinitrogen to two molecules of ammonia in three successive two-electron reductions via diazene and hydrazine. The reduction is initiated by formation of hydrogen in stoichiometric amounts [2]. Acetylene is reduced to ethylene (but only very slowly to ethane), azide to nitrogen and ammonia, and cyanide to methane and ammonia. In the absence of a suitable substrate, hydrogen is slowly formed. Ferredoxin may be replaced by flavodoxin [see EC 1.19.6.1 nitrogenase (flavodoxin)]. The enzyme does not reduce CO (cf. EC 1.18.6.2, vanadium-dependent nitrogenase ...
1G20: MgATP-Bound and nucleotide-free structures of a nitrogenase protein complex between the Leu 127 Delta-Fe-protein and the MoFe-protein.
1G20: MgATP-Bound and nucleotide-free structures of a nitrogenase protein complex between the Leu 127 Delta-Fe-protein and the MoFe-protein.
The mechanism by which planktonic marine cyanobacteria of the genus Trichodesmium fix N2 aerobically during photosynthesis without heterocysts is unknown. As an aid in understanding how these species protect nitrogenase, we have developed an immunofluorescence technique coupled to light microscopy (IF-LM) with which intact cyanobacteria can be immunolabeled and the distribution patterns of nitrogenase and other proteins can be described and semiquantified. Chilled ethanol was used to fix the cells, which were subsequently made permeable to antibodies by using dimethyl sulfoxide. Use of this technique demonstrated that about 3 to 20 cells (mean +/- standard deviation, 9 +/- 4) consecutively arranged in a Trichodesmium trichome were labeled with the nitrogenase antibody. The nitrogenase-containing cells were distributed more frequently around the center of the trichome and were rarely found at the ends. On average 15% of over 300 randomly encountered cells examined contained nitrogenase. The ...
From ATP to electron transfer: Electrostatics and free-energy transduction in nitrogenase. Simulation of scanning tunneling microscope images of 1,3-cyclohexadiene bound to a silicon surface
Doug Rees had his first experience with electron transfer processes in microbes as an undergraduate studying cytochrome in Neurospora with Carolyn W. Slayman at Yale College where he completed his BS in Molecular Biophysics and Biochemistry in 1974. In 1980 he received a PhD in Biophysics, determining crystal structures of carboxypeptidase A with William Lipscomb at Harvard. While there he also became acquainted with multi-center electron-sharing bonds (e.g. in boranes). During a two year postdoctoral appointment at the University of Minnesota with James B. Howard, he successfully produced the first crystals of the nitrogenase iron protein from Azotobacter vinelandii. He has continued his work with several nitrogenases and has had a productive collaboration with Jim Howard for 35 years.. Professor Rees joined the faculty of the Department of Chemistry and Biochemistry at UCLA in 1982 and moved to Caltech in 1989. He is a member of the American Academy of Arts and Sciences and the National ...
Nitrogenases are vitally important enzymes that perform an amazing chemical reaction, the reduction of N2 to ammonia. In nitrogenases, iron-sulfur clusters cata...
Pelagic nitrogen fixation makes an important contribution to the fixed nitrogen budget of the worlds oceans. Filamentous and unicellular cyanobacteria are significant players in this process but less is known of the potential activity of heterotrophic diazotrophs, although they are present and can be quite numerous in the nitrogen-deplete surface waters of the tropical and sub-tropical oceans. In this study we focused on the potential activity of several clades of heterotrophic nitrogen-fixers identified by phylogenetic analysis of 44 non-Trichodesmium-related, nifH (encoding the Fe-subunit of nitrogenase) clones from the Arabian Sea. Specific Northern slot blot protocols were developed to quantify nifH mRNAs from each clade and showed that two groups of Gammaproteobacteria, including the previously characterized UMB clade, and a third, novel phylotype affiliated with cluster III anaerobes, were actively expressing nitrogenase in the equatorial waters of this region. Transcripts (nifH mRNAs) ...
The nitrogenase complex reduces the N2 gas to ammonium, but not to nitrate. The product of fixation is ammonium. The oxidation of ammonium to nitrite/nitrate happens later and as I already said this processs called nitrification ...
All we that studied Bios probably remember two known aspects of the symbiotic relationships of plant roots with microorganisms: 1) The bacterial Rhizobium nodules on the roots of legumes (Figure 1). These bacteria, with the nitrogenase complex, are among the few organisms capable of fixing atmospheric N2 transforming it into organic nitrogen, which is used…
When the heavier homologues KSCN and KSeCN are employed, the Fe(III) compounds 3 and 4 are isolated in low yield (Scheme 1). The formation of these compounds is unexpected, since generally no redox processes are encountered when pseudohalides coordinate to transition metals,15 which implies that the Cp′Fe-fragment is susceptible to redox chemistry. Furthermore, this redox behavior is apparently facilitated by the synergy between two or more Fe atoms, an effect that also accounts for the facile N2 release from [Bu4N]N3 in the presence of [(tbsL)Fe3(thf)].4 Furthermore, S-C bond cleavage of a SCN− ligand is a rare event, but has previously been observed in [Pd3(SCN)(μ3-CO)(μ-dppm)3]+ to form [Pd3(μ3-S)(CN)(μ-dppm)3]+.16 The FeMoco nitrogenase enzyme also transiently binds SCN− before reduction to HCN and H2S occurs; but the mechanism of this biological SCN− reduction remains unknown.17 Cleavage of the S-C and Se-C bond to form 3 and 4 requires that the Fe(II) atoms are oxidized to ...
W.B. Silvester While dinitrogen (N2) fixation occurs in many free-living bacteria in soil, it is only when bacteria such as Rhizobium species and Frankia enter symbiotic relationships with a plant that really large quantities of nitrogen are fixed.
Markus Ribbe did his PhD in the laboratory of Ortwin Meyer in Bayreuth on the oxygen-tolerant superoxide-dependent nitrogenase of Streptomyces ...
Bikram, or hot yoga, is a modern form of an ancient system of postures and breathing that developed many centuries ago in India. All forms of yoga are...
In field and pot experiments the effect of selected pesticides on the nitrogenase activity, num-ber of soil microorganisms, and yield of hybrid lucerne was investigated. The obtained results show that crop protection preparations applied in the experiment (seed dressing compound Funaben T and...
The mid-point potentials of the Fe protein components (Ac2 and Ac2* respectively) of the Mo nitrogenase and V nitrogenase from Azotobacter chroococcum were determined in the presence of MgADP to be −450 mV (NHE) [Ac2(MgADP)2-Ac2*ox.(MgADP)2 couple] and −463 mV (NHE) [Ac2* (MgADP)2-Ac2*ox.(ADP)2 couple] at 23 degrees C at pH 7.2. These values are consistent with a flavodoxin characterized by Deistung & Thorneley [(1986) Biochem. J. 239, 69-75] with Em = −522 mV (NHE) being an effective electron donor to both the Mo nitrogenase and the V nitrogenase in vivo. Ac2*ox.(MgADP)2 and Ac2*ox.(MgADP)2 were reduced by SO2.- (formed by the predissociation of dithionite ion, S2O4(2-)) at similar rates, k = 4.7 × 10(6) +/- 0.5 × 10(6) M-1.s-1 and 3.2 × 10(6) +/- 0.2 × 10(6) M-1.s-1 respectively, indicating structural homology at the electron-transfer site associated with the [4Fe-4S] centre in these proteins. ...
TY - JOUR. T1 - Nitrogenase activity, nodule respiration, and O2 permeability following detopping of alfalfa and birdsfoot trefoil. AU - Denison, R. Ford. AU - Hunt, Stephen. AU - Layzell, David B.. N1 - Copyright: Copyright 2017 Elsevier B.V., All rights reserved.. PY - 1992. Y1 - 1992. N2 - Gas exchange measurements and noninvasive leghemoglobin (Lb) spectrophotometry (nodule oximetry) were used to monitor nodule responses to shoot removal in alfalfa (Medicago sativa L. cv Weevlchek) and birdsfoot trefoil (Lotus corniculatus L. cv Fergus). In each species, total nitrogenase activity, measured as H2 evolution in Ar:O2 (80:20), decreased to 50% of the initial rate within 1 hour after detopping, and net CO2 production decreased to about 65% of the initial value. In a separate experiment in which nodule oximetry was used, nodule O2 permeability decreased 50% within 5 hours in each species. A similar decrease in the O2-saturated respiration rate (Vmax) for the nodule central zone occurred within 5 ...
TY - JOUR. T1 - Diversity and activity of alternative nitrogenases in sequenced genomes and coastal environments. AU - McRose, Darcy L.. AU - Zhang, Xinning. AU - Kraepiel, Anne M.L.. AU - Morel, Francois M. M.. N1 - Publisher Copyright: © 2017 McRose, Zhang, Kraepiel and Morel. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.. PY - 2017/2/28. Y1 - 2017/2/28. N2 - The nitrogenase enzyme, which catalyzes the reduction of N2 gas to NH4+, occurs as three separate isozyme that use Mo, Fe-only, or V. The majority of global nitrogen fixation is attributed to the more efficient canonical Mo-nitrogenase, whereas Fe-only and V-(alternative) nitrogenases are often considered backup enzymes, used when Mo is limiting. Yet, the environmental distribution and diversity of alternative nitrogenases remains largely unknown. We searched for alternative nitrogenase genes in sequenced genomes and used PacBio sequencing to explore the diversity of canonical (nifD) and alternative (anfD and vnfD) ...
Team WashU_StLouis The production of a bio-fertilizer could benefit the agricultural industry by decreasing the need for energy intensive nitrogen fixation processes. The nif cluster of Cyanothece 51142 consists of 29 genes that construct and regulate a nitrogenase protein complex, which catalyzes the fixation of atmospheric nitrogen. This year, our iGEM team aims to harness the power of nif to produce ammonia in Escherichia coli. After synthesizing a nif- containing plasmid (34 kbp) using the DNA assembler method (Shao et al 2009) and transforming that plasmid into E. coli, our team tested for nitrogenase activity using the acetylene reduction assay. The transformed E. coli were then compared to wild-type under limited nitrogen conditions to check for a competitive advantage. Future tests will evaluate the expression of various nitrogenase subunits, such as nifD and nifK. Our team also aims to further characterize the promoter sequences of the Cyanothece 51142 nif cluster. Between the cysE and ...
Colonization and nitrogenase activity of Triticum aestivum (cv. Baccross and Mahdavi) to the dual inoculation with Azospirillum brasilense and Rhizobium melilot
TY - JOUR. T1 - Distribution of soil nitrogen and nitrogenase activity in the forefield of a High Arctic receding glacier. AU - Turpin-Jelfs, Thomas. AU - Michaelides, Katerina. AU - Blacker, Joshua J.. AU - Benning, Liane G.. AU - Williams, James M.. AU - Anesio, Alexandre M.. PY - 2019/1/24. Y1 - 2019/1/24. N2 - Glaciers retreating in response to climate warming are progressively exposing primary mineral substrates to surface conditions. As primary production is constrained by nitrogen (N) availability in these emerging ecosystems, improving our understanding of how N accumulates with soil formation is of critical concern. In this study, we quantified how the distribution and speciation of N, as well as rates of free-living biological N fixation (BNF), change along a 2000-year chronosequence of soil development in a High Arctic glacier forefield. Our results show the soil N pool increases with time since exposure and that the rate at which it accumulates is influenced by soil texture. Further, ...
leaving the download Management of Biological Nitrogen Fixation for the Development of More Productive and Sustainable Agricultural Systems: Extended versions of papers presented at the Symposium on Biological Nitrogen of war has an Iranian research in Establishing the other pair of the Application. In this evaluation, a parole favors sent as the natural next-generation order for silencing veritable applications. stakeholders between Programmed Lines and satan problems are born to be.
nifB- MoFe protein (nifB-Av1), ΔnifE MoFe protein (ΔnifE Av1) and ΔnifZ MoFe protein ΔnifZ Av1) were obtained by chromatography on DE52, Sephacryl S-300 and Q-Sepharose columns from nifB point-mutated, nifE deleted and nifZ deleted mutant stains (UW45, DJ35 and DJ194) of Azotobacter vinelandii Lipmann, respectively. When complemented with nitrogenase Fe protein (Av2), ΔnifZ Av1 had partial activity and both nifB- Av1 and ΔnifE Av1 had hardly any activity, but could be obviously activated by FeMoco extracted from wild-type MoFe protein (OP Av1) or ΔnifZ Av1. After being incubated with excess O-phenanthroline (O-phen) for 150 min at 30 °C and subjected to chromatography on a Sephadex G-25 column in an Ar atmosphere, nifB- Av1©, ΔnifE Av1© and ΔnifZ Av1© were obtained, respectively. Based on a calculation of Fe atoms in the O-phen-Fe compound with ε512nm= 11 100, lost Fe atoms of nifB- Av1, ΔnifE Av1 and ΔnifZ Av1 were estimated to be 1.35, 2.89 and 8.44 per molecule of protein, ...
A dedicated and enthusiastic junior plant microbiologist with excellent academic achievements, previous work and research experiences in terrestrial ecology as well as environmental resource management to a total of 3 published articles. Her current research focus is biological nitrogen fixation by associative diazotrophic bacteria in non-leguminous plant systems, particularly investigating the functions of nitrogenase isozymes of a plant growth promoting bacteria Kosakonia radicincitans in biological nitrogen fixation in relation to nitrogen availability.. ...
1.0 1.1 Brigle, KE et al. (1987) Products of the iron-molybdenum cofactor-specific biosynthetic genes, nifE and nifN, are structurally homologous to the products of the nitrogenase molybdenum-iron protein genes, nifD and nifK. J. Bacteriol. 169 1547-53 PubMed GONUTS page ...
Last week, in Part 1 of this series on electrochemical ammonia synthesis technologies, I quoted a recent article by researchers at MIT that identified avenues for future research and development. One option was a biomimicry approach, learning from enzymatic catalysts, such as nitrogenases, which can either be incorporated into or provide inspiration for the design of electrocatalytic processes.. The nitrogenase enzyme, natures ammonia synthesis technology, was developed in an iterative innovation process, otherwise known as evolution, that took hundreds of millions of years to reach this level of efficiency. According to one group of electrochemists, who presented their results at the recent NH3 Energy+ conference, nitrogenase produces ammonia in nature with an enviable 75% process efficiency - so its no surprise that they are basing their industrial technology on it.. Read more. ...
Iron-sulphur (FeS) clusters are important cofactors for numerous proteins involved in electron transfer, in redox and non-redox catalysis, in gene regulation, and as sensors of oxygen and iron. These functions depend on the various FeS cluster prosthetic groups, the most common being [2Fe-2S] and [4Fe-4S] [(PUBMED:16221578)]. FeS cluster assembly is a complex process involving the mobilisation of Fe and S atoms from storage sources, their assembly into [Fe-S] form, their transport to specific cellular locations, and their transfer to recipient apoproteins. So far, three FeS assembly machineries have been identified, which are capable of synthesising all types of [Fe-S] clusters: ISC (iron-sulphur cluster), SUF (sulphur assimilation), and NIF (nitrogen fixation) systems.. In the NIF system, NifS and NifU are required for the formation of metalloclusters of nitrogenase in Azotobacter vinelandii, and other organisms, as well as in the maturation of other FeS proteins. Nitrogenase catalyses the ...
Diazotrophic microorganisms introduce biologically available nitrogen (N) to the global N cycle through the activity of the nitrogenase enzyme. The genetically conserved dinitrogenase reductase (nifH) gene is phylogenetically distributed across four clusters (I-IV) and is widely used as a marker gene for N2 fixation, permitting investigators to study the genetic diversity of diazotrophs in nature and target potential participants in N2 fixation. To date there have been limited, standardized pipelines for the nifH functional gene, which is in stark contrast to the rRNA gene. Here we present a bioinformatics pipeline for processing nifH amplicon datasets - NifMAP (NifH MiSeq Illumina amplicon Analysis Pipeline), which as a novel aspect uses Hidden-Markov models to filter out homologous genes to nifH. By using this pipeline, we evaluated the broadly inclusive primer pairs (Ueda19F-R6, IGK3-DVV, F2-R6) that target the nifH gene. To evaluate any systematic biases, the nifH gene was amplified with ...
The India-UK Nitrogen Fixation Centre (IUNFC) is a BBSRC-DBT joint-funded VJC aiming to tackle the problems of food security, the environmental and economic challenges of crop production and soil improvement in India through scientific research on nitrogen fixation. Formed in 2016, with lead investigators in India and the UK and a total of eight additional co-investigators from prestigious institutes and universities in both countries, IUNFC is carrying out world-class fundamental and applied research on biological nitrogen fixation (BNF) to increase scientific knowledge. In the short/medium term, this knowledge will lead to changes in agricultural practices in India, bringing economic, environmental and social benefits. In the longer term, it will provide a platform to engineer nitrogen fixation in cereal crops with implications for worldwide food security.. IUNFC unites eleven renowned experts in all aspects of BNF at six research centres in India and three in the UK under the leadership of ...
Automatic Addition Control of the External Carbon Source by the Measurement of ORP in Biological Nitrogen Removal Process - Biological nitrogen removal;External carbon source;COD/N ratio;Oxidation-reduction potential;PID control;
The research in our group is multidisciplinary, shifting from biochemistry and bioengineering to bioelectrochemistry and nanotechnology. Generally, we use the unique properties of nanomaterials (electrical, optical) with enzymes to gain synergetic effect in catalysis and sensing. Our goal is to construct novel biohybrid systems with unnatural triggers for enzyme activation. To gain that, we use electrodes or nanomaterials which allow directed or mediated electron transfer into the enzymes active sites. As a multi-disciplinary lab, our tools vary from electrochemical setups and glove box to electrophoresis and separation columns. Major research direction aims to form biohybrids which activates nitrogenase by light stimuli. Furthermore, the nitrogenase will be further coupled to electrodes for the construction of biofuel or photobioelectrochemical cells. The work in the lab is focused on several topics ...
To their surprise, the interaction between Ki-67 and NIFK simply promotes the growth of lung cancer cells. However, besides from its tumor growth function shared with Ki-67, NIFK has its own special ability! NIFK turns out to be the key player that triggers lung cancer cell to spread from primary site to other parts of the body. NIFK can inhibit CK1, a molecular brake to stop the cell from keep on dividing and metastasis. What NIFK does is to inhibit RUNX1, a transcription factor of CK1, without RUNX1, CK1 cannot be produced, thereby, everything goes out of control!. NIFK is a promising surrogate marker for identifying high risk lung cancer patients. Lung cancer patients with higher tumor NIFK level tend to have a rapid disease progression and need more intensive treatment. commented by Chia-Yi Su, one of the co-first authors of the study, who is also a pathologist herself.. As for the following steps, Dr. Tsung-Chieh Lin, the first author of this research, expressed even more enthusiasm. The ...
A large number of fundamental chemical processes require the activation or cleavage of strong bonds in small, inert molecules. In the biologically essential process of nitrogen fixation, the enzyme nitrogenase manages to break one of the strongest chemical bonds in nature under mild conditions. In stark contrast, the corresponding industrial process, the Haber-Bosch method, requires extreme temperatures and pressures to perform the same function.
Rates of N2 fixation can be measured by a number of techniques to address questions of nodule efficiency and nitrogen cycling in agricultural and natural plant systems. Nitrogenase is pivotal for initial reduction of N2 but this same enzyme will also reduce acetylene (C2H2) to ethylene (C2H4).
Follow these practical tips and guidelines to mitigate or eliminate the risk of injury to themselves or others when transporting and handling acetylene.
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Ribbe M.W., Burgess B.K. (2002) Characterization of the E146D Fe Protein Mutant of Azotobacter Vinelandii: Function in Nitrogenase Turnover, Femo Cofactor Biosynthesis and Insertion. In: Pedrosa F.O., Hungria M., Yates G., Newton W.E. (eds) Nitrogen Fixation: From Molecules to Crop Productivity. Current Plant Science and Biotechnology in Agriculture, vol 38. Springer, Dordrecht. https://doi.org/10.1007/0-306-47615-0_ ...
The hypothesis of respiratory protection, originally formulated on the basis of results obtained with Azotobacter species, postulates that consumption of O(2) at the surface of diazotrophic prokaryotes protects nitrogenase from inactivation by O(2). Accordingly, it is assumed that, at increased ambient O(2) concentrations, nitrogenase activity depends on increased activities of a largely uncoupled respiratory electron transport system. The present review compiles evidence indicating that cellular O(2) consumption as well as both the activity and the formation of the respiratory system of Azotobacter vinelandii are controlled by the C/N ratio, that is to say the ratio at which the organism consumes the substrate (i.e. the source of carbon, reducing equivalents and ATP) per source of compound nitrogen. The maximal respiratory capacity which can be attained at increased C/N ratios, however, is controlled, within limits, by the ambient O(2) concentration. When growth becomes N-limited at increased C/N
TY - JOUR. T1 - Nitrogen isotope fractionation by alternative nitrogenases and past ocean anoxia. AU - Zhang, Xinning. AU - Sigman, Daniel Mikhail. AU - Morel, Francois M. M.. AU - Kraepiel, Anne M.L.. PY - 2014/4/1. Y1 - 2014/4/1. N2 - Biological nitrogen fixation constitutes the main input of fixed nitrogen to Earths ecosystems, and its isotope effect is a key parameter in isotope-based interpretations of the N cycle. The nitrogen isotopic composition (δ15N) of newly fixed N is currently believed to be∼-10/00, based on measurements of organic matter from diazotrophs using molybdenum (Mo)-nitrogenases. We show that the vanadium (V)- and iron (Fe)-only alternative nitrogenases produce fixed N with significantly lower δ15N (-6 to -70/00). An important contribution of alternative nitrogenases to N2 fixation provides a simple explanation for the anomalously low δ15N (,-20/00) in sediments from the Cretaceous Oceanic Anoxic Events and the Archean Eon. A significant role for the alternative ...
The transition metal vanadium (V) has relatively few known biological functions. It is found in marine algaes haloperoxidase enzymes (5). It also is accumulated by ascidians (11), but its biological function (if any) in these organisms is still mysterious. Most importantly, V is found at the active center of an alternative form of the enzyme nitrogenase, which fixes atmospheric N2 gas into bioavailable ammonia and is responsible for the natural input of new nitrogen into the earths ecosystems. The molybdenum (Mo)-nitrogenase, which is the most common and efficient form of the enzyme, has a Mo cofactor at its active site, but when Mo is not available, some bacteria can express an alternative V-nitrogenase, which uses a V cofactor in place of Mo (3, 4). Some organisms also have an Fe-only nitrogenase, which requires only Fe at its active center and is used when neither Mo nor V is available (14, 20).. V is toxic at high concentrations. Unlike most transition metals (but like Mo), the most stable ...
Electron-delivering protein manipulates natural catalyst, changing ideas about fertilizer production. Results: In industry, synthesizing ammonia for fertilizers uses massive amounts of hydrogen, typically generated from fossil fuels, but in nature, the nitrogenase enzyme produces ammonia without added hydrogen. In studying the enzyme, scientists came up against a protein, called the Fe protein. This little protein delivers electrons to the larger nitrogenase MoFe enzyme. The smaller proteins actions limit the enzymes speed. Recently, scientists at Pacific Northwest National Laboratory and three universities found that the smaller protein and larger enzyme roll across each other, likely pushing at the MoFe surface to deliver electrons.. Why It Matters: Producing ammonia for the worlds crop fertilizers consumes 1 to 2 percent of all the energy produced by humankind. Part of that energy is used to generate hydrogen gas, which is combined with nitrogen gas in the Haber-Bosch process. This ...
Two genetically distinct flavodoxins, designated AcFldA and AcFldB, were isolated from Azotobacter chroococcum (MCD1155) grown under nitrogen-fixing conditions. AcFldA and AcFldB differ in their midpoint potentials for the semiquinone-hydroquinone couple (Em -305 mV and -520 mV respectively). Only AcFldB was competent to act as an electron donor to the Mo-containing nitrogenase of A. chroococcum. The N-terminal amino acid sequence (20 residues) of AcFldB was identical with that predicted from the nifF DNA sequence of A. vinelandii OP [Bennett, Jacobsen & Dean (1988) J. Biol. Chem. 263, 1364-1369], suggesting that AcFldB is the nifF gene product of A. chroococcum (MCD1155). Direct fast reversible electrochemistry of these flavodoxins has been achieved at a polished edge-plane graphite electrode using the aminoglycoside neomycin as a promoter. The heterogeneous rates of electron transfer between the graphite electrode and AcFldA and AcFldB were determined to be 1.2 x 10(-3) cm.s-1 and 2.0 x 10(-3) ...
By Felix D. Dakora. This quantity covers contemporary advancements in either basic and utilized examine in organic nitrogen fixation. It emphasizes the applying of organic nitrogen fixation for sustainable agriculture, which should still result in poverty relief, environmental safeguard, and stable agricultural practices more often than not. the jobs of, and advances in, plant breeding, plant molecular biology, nodule body structure, and symbiotic and associative interactions among vegetation and microbes in maintaining agricultural productiveness and soil fertility are defined. The evolution of symbioses and nitrogen fixation also are coated during this quantity. to make sure excessive agricultural productiveness, whereas maintaining the surroundings (both soil and water resources), calls for plant cultivars that still reply to helpful microbes. the amount, for this reason, describes the body structure and genomics of nitrogen-fixing micro organism including the biochemistry and molecular ...
Channel that opens in response to stretch forces in the membrane lipid bilayer. May participate in the regulation of osmotic pressure changes within the cell.
Sampling days in the field have been long yet extremely productive. We have collected nitrogen fixation data on primary producers found in four streams with varying temperatures. We can calculate the rate that primary producers are fixing nitrogen using a technique called Acetylene Reduction Assay or ARA. This is one method of measuring fixation which allows us to compare how rates of fixation change across a temperature gradient. You may be thinking Whoa! Back up. What is this girl talking about? Let me explain. Some primary producers, for example, one of my favorites, Nostoc Pink, can take nitrogen gas (N2), which is abundant in the air, and utilize the nitrogen for growth and other critical cellular processes. But for the organism to use the nitrogen from N2 gas, it must be converted into a usable form of nitrogen. One particular enzyme known as nitrogenase allows for some organisms to be able to do just that! This enzyme breaks the bonds in N2 gas, or as we call it, fixes N2 gas, and ...
Beijerinck, M. W. Über oligonitrophile Mikroben. Zbl. Backt. 7, 561-582 (1901). Benson, D. R. & Silvester, W. B. Biology of Frankia strains, actinomycete symbionts of actinorhizal plants. Microbiological Reviews 57, 293-319 (1993).
The [email protected] Centre provides a platform for research students to deposit their Ph.D. theses and make it available to the entire scholarly community in open access. Shodhganga Mirror Site ...
The endosymbiotic relationship between nitrogen-fixing rhizobial bacteria and certain plants (legumes) is of the utmost importance for the nitrogen cycle in the biosphere and hence an object of intense study by specialists from various areas of biology. What is more, although the use of artificial nitrogen-containing fertilizers made it possible to bypass the strict dependence on this process, its understanding is still crucial for the efficient agriculture. Biological nitrogen fixation requires nitrogenase, an enzyme present in, among others, rhizobial bacteria but absent in plants. The rhizobia are a diverse range of soil bacteria. It is thought that after the symbiotic capabilities were first acquired by some of them, they spread by means of horizontal transfer of a plasmid or genomic island containing genes important for the process. The symbiotic relationship between the two symbionts depends on the formation of invasion structures (nodules) by the host, allowing bacteria to enter the plant ...
Learning from nature: The development of an MoS2/Ta3N5 nanocomposite as a catalyst for selective aerobic oxidation by O2 activation was inspired by the nitrogenase enzymes in nature. The superior performance of this biomimetic catalyst, which shows potential for the selective oxidation of multifunctional substrates (see picture), results from the integration of Ta3N5 and MoS2 at the nanoscale and the synergistic enhancement of their activity. ...
Azotobacter vinelandii bacteriophage PAV-1 ATCC ® 13705-B1™ Designation: PAV-1 TypeStrain=False Application: Characterization
Biohazard level, growth media and temperature, gram stain, industrial applications and more information for Azotobacter vinelandii.
SWISS-MODEL Repository entry for C1DM66 (PDXB_AZOVD), Erythronate-4-phosphate dehydrogenase. Azotobacter vinelandii (strain DJ / ATCC BAA-1303)
The ability of bacteria to respond to a multitude of environmental signals and integrate these signals to trigger adaptive responses provides a successful strategy for survival in rapidly changing environments. In many cases integration can be achieved via the interlinking of different regulatory circuits in which various master regulators respond to different environmental cues. However, in some systems an economy of scale can be achieved if individual regulatory proteins are able to respond to more than one input signal. In this review we consider a particular example where multiple signals are integrated by a regulatory protein complex to finely tune transcriptional regulation of nitrogen fixation in free-living diazotrophic bacteria.. The ability to fix atmospheric nitrogen to ammonia by using the enzyme nitrogenase enables diazotrophs not only to survive but also to proliferate under conditions of extreme fixed-nitrogen deprivation. This strategy, however, incurs an energetic penalty since ...
Learning objectives:. Biotechnology has made major contributions in agriculture with regards to improvement, production and management of agricultural produces and practice. From hybrid technology to precise genetic manipulation- everything has profoundly impacted this sector. The objectives of the course on Agricultural Biotechnology are: i) understanding the basics of agricultural principles and practice and applying modern biotechnology tools for their improvements ii) learn and understand the latest innovations and discoveries that have been applied in the fields of plant and animal biotechnology iii) raising awareness about the prospects and cautions of releasing GMOs in the environment.. Course content: The course will cover the following aspects of Agricultural Biotechnology:. Plant growth and development: Plant growth regulators; Biological nitrogen fixation; Biofertilizers-types, production, VAM, Rhizobium, Azotobacter, Mycorhiza, Actinorhiza; Vermicomposting technology; ...
Interpretive Summary: Technical Abstract: A lush field consisting of a mixture of grass and legumes is the goal of many producers. Such a production system has many benefits. The most important in times of high fertilizer prices is the reduced need for nitrogen (N) because of the legumes capacity for biological nitrogen fixation. However, attaining a productive grass-legume mixture can be frustrating, and stands with the desired mixture are often short-lived. Alfalfa is an excellent legume for growth in a mixture because it is highly productive, is widely adapted, has an extensive root system that taps water and nutrients deeper in soil, and has a canopy that allows good light penetration. However, alfalfa has been developed primarily for growth in monoculture, and a different set of characteristics are necessary for growing in a mixture. For maximum productivity with grasses, a redesigned alfalfa will need to supply N to the grass component, have enhanced ability to acquire potassium (K) and ...
Signum Signum is a bio-prepared developed exclusively by Rizobacter It acts as a generator of molecular signals that activates metabolic processes earlier in bacteria and plants, which allows maximizing the development of leguminous plants.. Advantages • It has Bradirhizobium bacteria in a better physiological state than the ones obtained by traditional methods thanks to its formulation under Osmo-protector technology (TOP).. • It is an activator of vegetable and microbial physiology.. • It acts on the germination and crops development.. • It promotes the activity in the rhizosphere.. • Induces diseases resistance by activating defensive signals.. • It improves the performance before stress situations such as water deficit, soil acidity and low temperatures.. • It favors the positive interaction with other beneficial soil microorganisms.. • It maximizes BNF (Biological nitrogen fixation) even under stress conditions.. • It increases grain performance and ...
Scientists are trying to unlock the genetic and biochemical secrets of enzymes that could one day make crops more productive and reduce the need for fertilizer, easing world hunger and saving billions of dollars in agricultural costs.. The enzymes--nitrogenase and hydrogenase--are present in bacteria called Rhizobia, which grow on the roots of plants such as soybeans and other legumes, enabling those crops to take nitrogen directly from the air. The bacteria fix nitrogen into the soil and then nitrogenase makes ammonia fertilizer by combining hydrogen with the nitrogen, saving U.S. farmers about $8 billion in fertilizer costs annually.. Most crops, such as corn and wheat, cannot make their own fertilizer. They must be grown with nitrogen-based fertilizers, which are costly and difficult to produce.. You have to physically combine hydrogen and nitrogen at very high pressure, said Hopkins Biology Professor Robert Maier.. Another economic factor is the price of nitrogen, which is subject to ...
Mineral nturient defiencies are a major constraint limiting legume nitrogen fixation and yield. In this review general techniques for assessing nutrient involvement in symbiotic nitrogen fixation are...
TY - JOUR. T1 - Electronic Selectivity Tuning in Titanium(III)-Catalyzed Acetylene Cross-Dimerization Reactions. AU - Oshovsky, Gennady V.. AU - Hessen, Bart. AU - Reek, Joost N. H.. AU - de Bruin, Bas. PY - 2011/11/28. Y1 - 2011/11/28. N2 - The reactivity of open-shell titanium(III) complexes in organometallic catalysis is associated with many open questions, in particular regarding the electronic structure of catalytic intermediates and transition states. The unpaired electron density in principle allows for radical-type reactivity, while at the same time empty d orbitals allow more traditional cis-coordination insertion pathways. In this paper we investigated the (Cp*)(2)Ti-III-catalyzed cross-dimerization of aliphatic and aromatic acetylenes, focusing on the reactivity of two different aliphatic acetylenes with a series of different aromatic acetylenes. The applied aliphatic acetylenes 1a (4-methylpent-1-yne) and 1b (N,N-dimethyl-N-propargylamine) have the same size but different ...
Nitrogen Fixation Definition - Nitrogen fixation is a chemical process that converts atmospheric nitrogen into ammonia, which is absorbed by organisms...
The substrate saturation and temperature-dependent kinetic properties of soluble and membrane-bound forms of acetylcholinestarase (A C h E) from brain and butyrylcholinester- ase (B C h E) from heart and liver were examined. In simultaneous studies these parameters were also measured for A C h E in erythrocyte membranes and for B C h E in the serum from rat and humans. For both soluble and membrane-bound forms of the enzyme from the three tissues, two components were discernible. In the brain, K m of component I (high affinity) and component II (low affinity) was somewhat higher in membrane-bound form than that of the soluble form components, while the Vmax values were significantly higher by about five fold. In the heart, K m of component II was lower in membrane-bound form than in the soluble form, while Vmax for both the components was about four to six fold higher in the membrane-bound form. In the liver, Vmax was marginally higher for the two components of the membrane-bound enzyme; the K m ...
[116 Pages Report] Check for Discount on Global Acetylene Gas Market Professional Survey Report 2016 report by QYResearch Group. Notes: Production, means the output of Acetylene Gas Revenue, means...
Page contains details about sodium carboxymethylcellulose-bound urchin-like CoSe2/acetylene black . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
The choice of an appropriate hedgerow species is one of the most critical decisions in exploiting the value of a contour hedgerow system. The implications
A common use of ethyne, also called acetylene, is as a fuel in welding. An acetylene flame can reach temperatures of close to 6,000 degrees Fahrenheit. Acetylene is also used for making carbon...
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atmospheric ammonia leaching_Haber process Chat Online The Haber process, also called the HaberBosch process, is an artificial nitrogen fixation process and is the main industrial procedure fo
You can find the answer to many of the questions you might have regarding different food assistance programs for older adults by going to the following web addresses:. Stay Strong Stay Healthy Stay Strong, Stay Healthy (SSSH) is an evidenced based eight-week program for older adults that meets the recommendation for healthy muscle strength. The programs goal is to improve health and quality of life.. Kansas Food Assistance Program Overview.. Kansas Food Assistance Program Brochures and inserts in English and Spanish.. Kansas Department for Aging and Disability Services-- Find out about your local senior center, or answers about issues facing seniors, or how to get older Americans Act meals (congregate/home delivered) for senior adults.. Kansas Department for Children and Families has information about the Kansas Food Assistance Program eligibility requirements and an application for services. Other services include the food commodity program, medical assistance, and more.. Posters-- Monthly ...
The enzyme nitrogenase is one of the few enzymes that can catalyze the process. The enzyme occurs in Rhizobium bacteria. There ... Nitrogenase (nitrogen fixation)[edit]. The fixation of atmospheric nitrogen is a very energy-intensive process, as it involves ... Chan MK, Kim J, Rees DC (May 1993). "The nitrogenase FeMo-cofactor and P-cluster pair: 2.2 A resolution structures". Science. ...
Molybdenum-dependent nitrogenase is the most commonly present nitrogenase. The different types of nitrogenase can be determined ... nifH has two similar genes anfH and vnfH that also encode for the nitrogenase reductase component of the nitrogenase complex ... Peterson, Richard B.; Wolk, C. Peter (1 December 1978). "High recovery of nitrogenase activity and of 55Fe-labeled nitrogenase ... the nifH gene is used to identify the presence of molybdenum-dependent nitrogenase followed by closely related nitrogenase ...
Ribbe, M. W.; Hu, Y.; Hodgson, K. O.; Hedman, B. (2014). "Biosynthesis of Nitrogenase Metalloclusters". Chem. Rev. 114 (8): ...
... (FeMo cofactor) is the primary cofactor of nitrogenase. Nitrogenase is the enzyme that catalyzes the conversion of ... Isolation of the FeMo cofactor from nitrogenase is done through centrifugal sedimentation of nitrogenase into the MoFe protein ... Einsle, O (2014). "Nitrogenase FeMo Cofactor: an Atomic Structure in Three Simple Steps". J. Biol. Inorg. Chem. 19 (6): 737-745 ... Hallmen, P. P.; Kästner, J. "N2 Binding to the FeMo-Cofactor of Nitrogenase. Z. Anorg. Allg. Chem. 2014. doi:10.1002/zaac. ...
nifK encodes for B-subunit of Component 1 of nitrogenase. nifD encodes for alpha subunit of component 1 of nitrogenase. nifH ... EhNifS and EhNifU were found to be necessary and sufficient for Fe-S clusters of non-nitrogenase Fe-S proteins to form under ... Mo-Fe-co catalytic site for nitrogenase.) nifQ is not absolutely essential. nifJ operon:The nifJ gene encodes for the pyruvate- ... This enzyme is involved in electron transfer to nitrogenase. nifUSVM operon: The nifS, nifV and nifM genes encode for a protein ...
Subject of this work include nitric oxide synthase, cytochrome P450, nickel-iron hydrogenase, and nitrogenase. In 2012, he ... Hoffman BM, Lukoyanov D, Dean DR, Seefeldt LC (2013). "Nitrogenase: A Draft Mechanism". Accounts of Chemical Research. 46 (2): ...
The best-studied nitrogenase up-to-date is Mo nitrogenase with M-cluster and P-cluster bearing important roles in substrate ... Nitrogenase is a metallozyme with essential function in the biological nitrogen fixation reaction. The M-cluster ([MoFe7S9C- ... The active site of Mo nitrogenase is the M-cluster, a metal-sulfur cluster containing a carbide at its core. Within the ... Wiig JA, Hu Y, Chung Lee C, Ribbe MW (September 2012). "Radical SAM-dependent carbon insertion into the nitrogenase M-cluster ...
"Biosynthesis of Nitrogenase Metalloclusters". Chemical Reviews. 114 (8): 4063-4080. doi:10.1021/cr400463x. PMC 3999185. PMID ...
Burges BK, Lowe DJ (1996). "Mechanism of Molybdenum Nitrogenase". Chemical Reviews. 96: 2983-3011. doi:10.1021/cr950055x. PMID ... the Mo-Fe protein of nitrogenase catalyzes the conversion of N2 to NH3 in nitrogen fixation. Of more relevance to human biology ...
Nitrogenase reveals its inner secrets". Science. 297 (5587): 1654-5. doi:10.1126/science.1076659. PMID 12215632. S2CID 82195088 ...
Kim, Jongsun; Rees, Douglas C. (1994). "Nitrogenase and biological nitrogen fixation". Biochemistry. 33 (2): 389-97. doi: ... oxidative coupling of two amines via a phenolic radical mechanism or fixation of nitrogen via nitrogenase. Three total ...
ISBN 0-387-25495-1. Nitrogenase activity: Kelley, Bruce C.; Jouanneau, Yves; Vignais, Paulette M. (1979). "Nitrogenase activity ...
Nitrogenase, an enzyme that contains a MoFe cluster, can be leveraged to fix atmospheric nitrogen, i.e. convert nitrogen gas ... Milton, Ross D.; Minteer, Shelley D. (2019-12-17). "Nitrogenase Bioelectrochemistry for Synthesis Applications". Accounts of ...
Nitrogenase is expressed under nitrogen limitation. Normally, the expression is regulated via negative feedback from the ... All diazotrophs contain iron-molybdenum or -vanadium nitrogenase systems. Two of the most studied systems are those of ... Aerobes-these species require oxygen to grow, yet their nitrogenase is still debilitated if exposed to oxygen. Azotobacter ... and supplied at a rate that will not harm the nitrogenase. Frankias-much less is known about these 'actinorhizal' nitrogen ...
The reason for this is that the enzyme responsible for nitrogen fixation in diazotrophs, nitrogenase, uses iron as a cofactor. ... Oxygen is especially toxic to nitrogenase. One way in which nitrogen-fixing cyanobacteria, such as those in the genera "Nostoc ... one of the ways by which Crocosphaera watsonii protects its nitrogenase from oxygen is through the adaptation of a diel rhythm ... and the iron can be used in other processes such as nitrogen fixation by nitrogenase. This mechanism reduces the iron ...
Other organisms require additional metals as enzyme cofactors, such as vanadium in the nitrogenase of the nitrogen-fixing ... Eady RR (July 1988). "The vanadium-containing nitrogenase of Azotobacter". BioFactors. 1 (2): 111-6. PMID 3076437. Chan MK, ...
Azonexus fungiphilus possesses the nitrogenase-gene nifH. "LSPN LPSN/". Retrieved 2013-08-15. Straininfo of Azonexus ...
doi:10.1021/ja01318a036.. Lineweaver H, Burk D, Deming, W E (1934). "The dissociation constant of nitrogen-nitrogenase in ...
Two main enzymes produce hydrogen in microbes, hydrogenase and nitrogenase; Cyanothece has both enzymes. The nitrogenase fixes ... PCC 7425's nitrogenase cluster is arranged differently from the other five strains and can only fix nitrogen anaerobically. ... In a very energy-intensive process, nitrogenase is first synthesized and then takes N2 from the air, combining it with protons ... Decreasing the oxygen in the cell allows the oxygen-sensitive nitrogenase to fix nitrogen from the air for the organism's needs ...
Lineweaver H, Burk D, Deming, W E (1934). "The dissociation constant of nitrogen-nitrogenase in Azobacter". Journal of the ...
"X-ray emission spectroscopy evidences a central carbon in the nitrogenase iron-molybdenum cofactor". Science. 334 (6058): 974-7 ... "Evidence for interstitial carbon in nitrogenase FeMo cofactor". Science. 334 (6058): 940. Bibcode:2011Sci...334..940S. doi: ...
Richard Holm's work on mimics of nitrogenase and creation of iron sulfur clusters. Stephen Lippard's work on MMO. Thomas ... This includes the oxygen evolving complex and nitrogenase. In an effort to understand these enzymes, small molecule analogs are ...
Gaby, J. C.; Buckley, D. H. (2011). "A global census of nitrogenase diversity". Environ. Microbiol. 13 (7): 1790-1799. doi: ... occurs when atmospheric nitrogen is converted to ammonia by a nitrogenase enzyme.[1] The overall reaction for BNF is: N. 2. +. ... 2 substrate.[13] In free-living diazotrophs, nitrogenase-generated ammonia is assimilated into glutamate through the glutamine ... Eukaryotic Nitrogenase EngineeringEdit. Some scientists are working towards introducing the genes responsible for nitrogen ...
These bacteria perform daily cycling of their nitrogenase enzyme. New molecules of nitrogenase are synthesized every morning, ... Capone, D. G.; O'Neil, J. M.; Zehr, J.; Carpenter, E. J. (1990). "Basis for diel variation in nitrogenase activity in the ... However, a genetic analysis of the nitrogenase nifH gene sequences of Trichodesmium spp, including T. thiebautii, revealed a ... and will experience a reduction in nitrogenase activities when these other nitrogen sources are available to it. Trichodesmium ...
His interest in nitrogenase began in William Lipscomb's laboratory. In 2015 he received the FA Cotton Medal, and in 2020 he was ... with JB Howard: Nitrogenase: standing at the crossroads, Current Opinion in Chemical Biology, Volume 4, 2002, pp. 559-566 with ... 971-984 with FA Tezcan, JT Kaiser, D. Mustafi, MY Walton, JB Howard: Nitrogenase Complexes: Multiple Docking Sites for a ... 218-227 with JB Howard, et al.: Ligand binding to the FeMo-cofactor: structures of CO-bound and reactivated nitrogenase, ...
Nitrogenase (flavodoxin). 1.20: Acting on phosphorus or arsenic in donors. *Glutaredoxin *GLRX ...
Nitrogenase (flavodoxin). 1.20: Acting on phosphorus or arsenic in donors. *Glutaredoxin *GLRX ...
Nitrogenase, an oxygen-sensitive enzyme, is essential to this conversion. For the proper functioning of nitrogenase, the ...
Cai, Rong; Minteer, Shelley D. (2018-11-09). "Nitrogenase Bioelectrocatalysis: From Understanding Electron-Transfer Mechanisms ...
It has abundant of nitrogenase enzyme capable of nitrogen reduction. Beijerinckia is a genus of bacteria from the family of ...
... nitrogenase, vanadium (V) nitrogenase, and iron-only (Fe) nitrogenase. Molybdenum nitrogenase, which can be found in ... Vanadium nitrogenase and iron-only nitrogenase can both be found in select species of Azotobacter as an alternative nitrogenase ... For example, H2 competes with N2 but not acetylene for nitrogenase (leading to overestimates of nitrogenase by ARA). Bottle or ... No crystallographic analysis has been reported on substrate bound to nitrogenase. Nitrogenase is able to reduce acetylene, but ...
... vinelandii vanadium nitrogenase was resolved in 2017 (PDB: 5N6Y​). Compared to Mo nitrogenase, V nitrogenase replaces one ... Unlike molybdenum nitrogenase, vanadium nitrogenase can also reduce carbon monoxide to ethylene, ethane and propane but both ... Vanadium nitrogenase has an α2β2Ύ2 subunit structure while molybdenum nitrogenase has an α2β2 structure. Though the structural ... Like molybdenum nitrogenase, vanadium nitrogenase is easily oxidized and is thus only active under anaerobic conditions. ...
Pathways & interactions: Nitrogenase iron-iron protein, alpha chain (IPR011290). Pathways. KEGG * 00625+1.18.6.1 Chloroalkane ...
Nitrogenase-mimic iron-containing chalcogels. Jian Liu, Matthew S. Kelley, Weiqiang Wu, Abhishek Banerjee, Alexios P. Douvalis ... Nitrogenase-mimic iron-containing chalcogels. Jian Liu, Matthew S. Kelley, Weiqiang Wu, Abhishek Banerjee, Alexios P. Douvalis ... A nitrogenase-inspired biomimetic chalcogel system comprising double-cubane [Mo2Fe6S8(SPh)3] and single-cubane (Fe4S4) ... Nitrogenase-mimic iron-containing chalcogels for photochemical reduction of dinitrogen to ammonia. Jian Liu, Matthew S. Kelley ...
Nitrogenase. IV. Simple method of purification to homogeneity of nitrogenase components from Azotobacter vinelandii. Biochim. ... Biosynthesis of the nitrogenase active-site cofactor precursor NifB-co in Saccharomyces cerevisiae. View ORCID ProfileStefan ... Nitrogenase MoFe-protein at 1.16 A resolution: A central ligand in the FeMo-cofactor. Science 297, 1696-1700 (2002).. ... Formation of nitrogenase NifDK tetramers in the mitochondria of Saccharomyces cerevisiae. ACS Synth. Biol. 6, 1043-1055 (2017). ...
The PDB archive contains information about experimentally-determined structures of proteins, nucleic acids, and complex assemblies. As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
The key enzymatic reactions in nitrogen fixation are catalyzed by the nitrogenase complex, which has 2 components: the iron ... The reversible ADP-ribosylation of Arg-101 inactivates the nitrogenase reductase and regulates nitrogenase activity.By ... Nitrogenase iron protein 1Add BLAST. 289. Amino acid modifications. Feature key. Position(s). DescriptionActions. Graphical ... nitrogenase activity Source: CACAO ,p>Inferred from Mutant Phenotype,/p> ,p>Describes annotations that are concluded from ...
Earlier studies of electron transfer (ET) from the nitrogenase Fe protein to the MoFe protein concluded that the mechanism for ... Temperature invariance of the nitrogenase electron transfer mechanism.. [Diana Mayweather, Karamatullah Danyal, Dennis R Dean, ...
PROTEIN (NITROGENASE MOLYBDENUM IRON PROTEIN). A, C. 478. Klebsiella pneumoniae. Mutation(s): 0 Gene Names: nifD. EC: 1.18.6.1 ... PROTEIN (NITROGENASE MOLYBDENUM IRON PROTEIN). B, D. 519. Klebsiella pneumoniae. Mutation(s): 0 Gene Names: nifK. EC: 1.18.6.1 ... NITROGENASE MO-FE PROTEIN FROM KLEBSIELLA PNEUMONIAE, DITHIONITE-REDUCED STATE. *DOI: 10.2210/pdb1QGU/pdb ... The X-ray crystal structure of Klebsiella pneumoniae nitrogenase component 1 (Kp1) has been determined and refined to a ...
Interactions in the nitrogenase complex have broad implications for signal and energy transduction mechanisms in multiprotein ... Structure of ADP x AIF4(-)-stabilized nitrogenase complex and its implications for signal transduction.. Schindelin H1, Kisker ... The crystal structure has been determined for the complex between the Fe-protein and MoFe-protein components of nitrogenase ... The coupling of ATP hydrolysis to electron transfer by the enzyme nitrogenase during biological nitrogen fixation is an ...
In Vivo Kinetics of Nitrogenase Formation in Clostridium pasteurianum Message Subject (Your Name) has forwarded a page to you ... In Vivo Kinetics of Nitrogenase Formation in Clostridium pasteurianum. Belinda Seto, L. E. Mortenson ... Clostridium pasteurianum exhibits diauxic growth when grown in the presence of both NH3 and N2; no nitrogenase activity or ... An explanation of these results and their relation to possible models for the regulation of nitrogenase is given. ...
VnfH adopts the same conformation that was observed for NifH, the Fe protein of molybdenum nitrogenase, in complex with ADP, ... Dos Santos PC, Fang Z, Mason SW, Setubal JC, Dixon R (2012) Distribution of nitrogen fixation and nitrogenase-like sequences ... Howard JB, Kechris KJ, Rees DC, Glazer AN (2013) Multiple amino acid sequence alignment nitrogenase component 1: insights into ... Biological nitrogen fixation Vanadium nitrogenase Fe protein Dinitrogenase reductase X-ray crystallography ...
Mutant studies have evidenced that the activity of the nitrogenase FeMo-co is significantly influenced by the environment. In ... Mo-nitrogenase is the enzyme responsible for the conversion of atmospheric nitrogen to ammonia. Its active site is the iron- ... Mo-nitrogenase is the enzyme responsible for the conversion of atmospheric nitrogen to ammonia. Its active site is the iron- ... Influence of His-195 on the nitrogenase FeMo-cofactor activity. Clean Technology 2007. Chapter 3: Emissions, and Environmental ...
In vitro activation of inactive nitrogenase component I with molybdate.. P T Pienkos, S Klevickis, W J Brill ... In vitro activation of inactive nitrogenase component I with molybdate. Message Subject (Your Name) has forwarded a page to you ... When Azotobacter vinelandii was derepressed for nitrogenase synthesis in the presence of WO42- rather than MoO42-, it ... synthesized active component II and inactive component I of nitrogenase. This inactive component I could be activated in vitro ...
Nitrogenase in Azotobacter chroococcum and Klebsiella pneumoniae ROBERT R. EADY; ROBERT R. EADY ... Vanadium nitrogenase of Azotobacter chroococcum . MgATP-dependent electron transfer within the protein complex Biochem J ( ... Electron transfer to nitrogenase. Characterization of flavodoxin from Azotobacter chroococcum and comparison of its redox ... ROBERT R. EADY, CHRISTINA KENNEDY, BARRY E. SMITH, ROGER N. F. THORNELEY, GEOFFREY YATES, JOHN R. POSTGATE; Nitrogenase in ...
Nitrogenase diversity estimated by Shannon was again slightly higher for S. fallax (7.59), than for S. angustifolium (7.20; ... Figure 7. Phylogenetic composition of the nitrogenase gene (nifH) amplicon libraries of S. angustifolium (SA, circles) and S. ... Amplicon libraries of the nitrogenase gene (nifH) were explored using the FunGene Pipeline of RDP server2 with parameters ... Zehr, J. P., and Turner, P. J. (2001). "Nitrogen fixation: nitrogenase genes and gene expression," in Methods in Microbiology, ...
Nitrogenase bioelectrocatalysis: heterogeneous ammonia and hydrogen production by MoFe protein Author(s): Ross D. Milton, ... Bioelectroreduction of nitrogen to ammonia: the incorporation of nitrogenase within enzymatic biological fuel cells for ... Bioelectroreduction of nitrogen to ammonia: the incorporation of nitrogenase within enzymatic biological fuel cells for ... The In Vivo Potential-Regulated Protective Protein of Nitrogenase in Azotobacter vinelandii Supports Aerobic Bioelectrochemical ...
We demonstrate electrochemical control of the nitrogenase MoFe protein, in the absence of Fe protein or ATP, using europium(iii ... We demonstrate electrochemical control of the nitrogenase MoFe protein, in the absence of Fe protein or ATP, using europium(III ... Infrared spectroscopy of the nitrogenase MoFe protein under electrochemical control: potential-triggered CO binding ... Infrared spectroscopy of the nitrogenase MoFe protein under electrochemical control: potential-triggered CO binding P. ...
Nitrogenase catalyzes the conversion of dinitrogen gas (N2) and protons to ammonia and hydrogen gas (H2). This is a ... Thus, nitrogenase is not normally expressed or active in bacteria grown with a readily utilized nitrogen source like ammonium. ... Inactivation of the nitrogenase posttranslational modification system by a draT2 mutation resulted in increased H2 production ... GlnK2 was not well expressed in ammonium-grown NifA* cells and thus not available to activate the DraT2 nitrogenase ...
Fu H, Hartmann A, Lowery RG et al (1989) Posttranslational regulatory system for nitrogenase activity in Azospirillum spp. J ... Hartmann A, Fu H, Burris RH (1986) Regulation of nitrogenase activity by ammonium chloride in Azospirillum spp. J Bacteriol 165 ... Gerk LP, Gilchrist K, Kennedy IR (2000) Mutants with enhanced nitrogenase activity in hydroponic Azospirillum brasilense-wheat ... Moure VR, Danyal K, Yang Z-Y et al (2013) The nitrogenase regulatory enzyme dinitrogenase reductase ADP-ribosyltransferase ( ...
A large number of genes are necessary for the biosynthesis and activity of the enzyme nitrogenase to carry out the process of ... A large number of genes are necessary for the biosynthesis and activity of the enzyme nitrogenase to carry out the process of ... The multiplicity of the genes involved, the oxygen sensitivity of nitrogenase, plus the demand for energy and reducing power, ... In contrast, an analogous ETC module from mitochondria could not function in electron transfer to nitrogenase. However, this ...
EFFECT OF NITROGEN ON NITROGENASE ACTIVITY OF DIAZOTROPHS AND TOTAL BACTERIAL POPULATION IN RICE SOIL. by Journal of Animal ... Effect of N on Stenotrophomonas maltophila nitrogenase activity: Application of urea-N significantly affected nitrogenase ... APA style: EFFECT OF NITROGEN ON NITROGENASE ACTIVITY OF DIAZOTROPHS AND TOTAL BACTERIAL POPULATION IN RICE SOIL.. (n.d.) >The ... Nitrogenase enzyme activity was reduced with increased rate of urea-N application (Figure 1b). The bacteria showed highest ARA ...
Here we report the structural analysis of vanadium nitrogenase with a bound intermediate, interpreted as a μ2-bridging, ...
1. Nitrogenase activity of a strain of Azotobacter chroococcum lacking the structural genes for conventional nitrogenase ( ... The vanadium nitrogenase of Azotobacter chroococcum. Purification and properties of the VFe protein R R Eady; R R Eady ... The vanadium nitrogenase of Azotobacter chroococcum . Purification and properties of the Fe protein Biochem J (November,1988) ... Vanadium nitrogenase of Azotobacter chroococcum . MgATP-dependent electron transfer within the protein complex Biochem J ( ...
Phosphorus Deficiency Increases the Acetylene-Induced Decline in Nitrogenase Activity in Soybean (Glycine max (L.) Merr.). ... Ribet, J. and Drevon, J.-J. (1995) Phosphorus Deficiency Increases the Acetylene-Induced Decline in Nitrogenase Activity in ...
Characterization of mutants of these bacteria derepressed for synthesis of the nitrogenase complex in the presence of ammonium ... Nitrogen fixation by photosynthetic bacteria : (Rhodospirilum rubrum, Rhodopseudomonas capsulata, glutamine ,nitrogenase). Wall ...
Nitrogenase Activity Associated with Roots and Stems of Field-Grown Corn (Zea mays L.) Plants Helvecio De-Polli, Charles D. ... Corn (Zea mays L.) plants were assayed for nitrogenase activity (C2H2 reduction) during early ear development. Hybrid corn and ... Nitrogenase Activity Associated with Roots and Stems of Field-Grown Corn (Zea mays L.) Plants ... Nitrogenase Activity Associated with Roots and Stems of Field-Grown Corn (Zea mays L.) Plants ...
We demonstrate here that nitrogen fixation by this strain depends on vanadium and we show that its purified nitrogenase is a ... is due to its involvement at or near the site of reduction of N2 in conventional nitrogenase. To date, all nitrogenases which ... a conventional nitrogenase involving molybdenum and an alternative system which functions under conditions of Mo deficiency and ... in which the structural genes for conventional nitrogenase are deleted8. ...
Nitrogenase gene amplicons from global marine surface waters are dominated by genes of non-cyanobacteria. Publikation: Bidrag ... Nitrogenase gene amplicons from global marine surface waters are dominated by genes of non-cyanobacteria Forlagets udgivne ... Our analysis of 79,090 nitrogenase (nifH) PCR amplicons encoding 7,468 unique proteins from surface samples (ten DNA samples ...
Rhodobacter capsulatus Chemostat Energy supply Nitrogen levels C/N ratio Nitrogenase activities Nitrogenase expression ... Specific nitrogenase activity increased by a factor of ten between 3000 and 15000 lx and approached constancy above 15 000 lx. ... Control of nitrogenase in chemostat cultures of Rhodobacter capsulatus grown on ammonium at different illuminations. ... Dingler C, Kuhla J, Wassink H, Oelze J (1988) Levels and activities of nitrogenase proteins in Azotobacter vinelandii grown at ...
  • A usual assembly consists of two components: The heterotetrameric MoFe protein, a nitrogenase which uses the electrons provided to reduce N2 to NH3. (wikipedia.org)
  • The hydrolysis of ATP also causes a conformational change within the nitrogenase complex, bringing the Fe protein and MoFe protein closer together for easier electron transfer. (wikipedia.org)
  • The delta subunits are homologous to each other, and the alpha and beta subunits themselves are homologous to the ones found in MoFe nitrogenase. (wikipedia.org)
  • Earlier studies of electron transfer (ET) from the nitrogenase Fe protein to the MoFe protein concluded that the mechanism for ET changed during cooling from 25 to 5 °C, based on the observation that the rate constant for Fe protein to MoFe protein ET decreases strongly, with a nonlinear Arrhenius plot. (sigmaaldrich.com)
  • The crystal structure has been determined for the complex between the Fe-protein and MoFe-protein components of nitrogenase stabilized by ADP x AIF4-, previously used as a nucleoside triphosphate analogue in nucleotide-switch proteins. (nih.gov)
  • We demonstrate electrochemical control of the nitrogenase MoFe protein, in the absence of Fe protein or ATP, using europium( III / II ) polyaminocarboxylate complexes as electron transfer mediators. (rsc.org)
  • We show that cadmium sulfide (CdS) nanocrystals can be used to photosensitize the nitrogenase molybdenum-iron (MoFe) protein, where light harvesting replaces ATP hydrolysis to drive the enzymatic reduction of N 2 into NH 3 . (sciencemag.org)
  • In vivo, the MoFe protein component of nitrogenase is exclusively reduced by the ATP-hydrolyzing Fe protein in a series of transient association/dissociation steps that are linked to the hyderolysis of two ATP for each electron transeferred. (usu.edu)
  • and Minteer, Shelley D., "Nitrogenase bioelectrocatalysis: heterogeneous ammonia and hydrogen production by MoFe protein" (2016). (usu.edu)
  • During nitrogenase catalysis the Fe protein and the molybdenum-iron protein associate and dissociate in a manner resulting in the hydrolysis of two molecules of MgATP and the transfer of at least one electron to the MoFe protein. (montana.edu)
  • In a previous work, a non-native conformation of the Pcluster on a FeMoco-free nitrogenase MoFe protein (designated Av1) was identified. (grantome.com)
  • Pre-incubation of this form of MoFe protein at various time lengths with the nifH gene product, the nitrogenase Fe protein (designated Av2), will be performed prior to quench. (grantome.com)
  • The reduction of substrates catalyzed by nitrogenase normally requires nucleotide-dependent Fe protein delivery of electrons to the MoFe protein, which contains the active site FeMo cofactor. (elsevier.com)
  • Computational normal-mode analysis of the nitrogenase complex reveals coupling in the motions of the Fe protein and the region of the MoFe protein with these three amino acids, which suggests a possible mechanism for how Fe protein might communicate subtle changes deep within the MoFe protein that profoundly affect intramolecular electron transfer and substrate reduction. (elsevier.com)
  • Nitrogenase MoFe protein from Clostridium pasteurianum at 1.08 Å resolution: comparison with the Azotobacter vinelandii MoFe protein. (ebi.ac.uk)
  • Electron transfer between the Fe protein and the MoFe protein was investigated to help determine the initial electron transfer pathway in nitrogenase. (lsu.edu)
  • Electron spin resonance (esr) spectroscopy of nitrogen-fixing whole cells yielded g4.26 and g3.66 signals indicating the presence of nitrogenase molybdenum-iron (MoFe) protein. (lsu.edu)
  • Esr spectroscopy of whole cell multilayers (WCM) of Azotobacter vinelandii and Rhodospirillum rubrum was used to detect structural associations between nitrogenase MoFe protein and cell membrane. (lsu.edu)
  • These properties suggest that the MoFe protein of nitrogenase was oriented in response to the physical orientation of cellular membranes and that a structural association exists between this nitrogenase component and membrane in these organisms. (lsu.edu)
  • Nitrogenase MoFe-protein at 1.16 Å resolution: a central ligand in the FeMo-cofactor. (nature.com)
  • Here we report the structural analysis of vanadium nitrogenase with a bound intermediate, interpreted as a μ2-bridging, protonated nitrogen that implies the site and mode of substrate binding to the cofactor. (ovid.com)
  • The Mo nitrogenase carries at its active site a unique iron-molybdenum cofactor (FeMoco) that consists of an inorganic 7 Fe, 1 Mo, 1 C, 9 S core coordinated to the organic acid homocitrate. (upm.es)
  • Hinnemann, B & Nørskov, JK 2004, ' Chemical activity of the nitrogenase FeMo cofactor with a central nitrogen ligand: A density functional study ', Journal of the American Chemical Society , vol. 126, pp. 3920-3927. (dtu.dk)
  • How nitrogenase shakes--initial information about P-cluster and FeMo-cofactor normal modes from nuclear resonance vibrational spectroscopy (NRVS). (semanticscholar.org)
  • The data presented in the current study demonstrate the pivotal role of molybdenum in optimal N-2 fixation and provides direct evidence that the inability of a tungsten-substituted nitrogenase to reduce N-2 is due to the difficulty to effectively reduce the FeW cofactor beyond its semireduced state. (uni-bielefeld.de)
  • Another step has been taken towards explaining the molecular mechanisms of biological fixation of nitrogen by the enzyme nitrogenase: Dr. Daniel Sippel from Prof. Dr. Oliver Einsle 's work group at the Institute of Biochemistry of the University of Freiburg has shown that the iron-vanadium cofactor (FeVco) of the enzyme can release and re-bind one single sulfur ion. (uni-freiburg.de)
  • Previously, the Freiburg researchers were able to partly analyze the center of another nitrogenase, the iron-molybdenum cofactor (FeMoco). (uni-freiburg.de)
  • From there, plasma membrane iron transporters move it into rhizobia-containing cells, where iron is used as the cofactor of multiple plant and rhizobial proteins (e.g. plant leghemoglobin and bacterial nitrogenase). (plantphysiol.org)
  • A large number of genes are necessary for the biosynthesis and activity of the enzyme nitrogenase to carry out the process of biological nitrogen fixation (BNF), which requires large amounts of ATP and reducing power. (jic.ac.uk)
  • Genes required for nitrogen fixation can be considered as three functional modules encoding electron-transport components (ETCs), proteins required for metal cluster biosynthesis, and the 'core' nitrogenase apoenzyme, respectively. (jic.ac.uk)
  • Biosynthesis of FeMo-co occurs outside nitrogenase through a complex and highly regulated pathway involving proteins acting as molecular scaffolds, metallocluster carriers or enzymes that provide substrates in appropriate chemical forms. (upm.es)
  • In the phototrophic non-sulfur bacterium Rhodobacter capsulatus, the biosynthesis of the conventional Mo-nitrogenase is strictly Mo-regulated. (uni-bielefeld.de)
  • Though the structural genes encoding vanadium nitrogenase show only about 15% conservation with molybdenum nitrogenases, the two nitrogenases share the same type of iron-sulphur redox centers. (wikipedia.org)
  • Microbial fingerprints obtained by PCR-single-strand conformation polymorphism of 16S rRNA and nitrogenase-encoding ( nifH ) genes were highly similar for both Sphagnum species. (frontiersin.org)
  • nifA* mutants of the purple nonsulfur phototrophic bacterium Rhodopseudomonas palustris express nitrogenase genes constitutively and produce H2 when grown with ammonium as a nitrogen source. (washington.edu)
  • In addition, the NifA* strain had elevated nitrogenase activity due to overexpression of the nif genes, and this increased amount of expression overwhelmed a basal level of activity of DraT2 in ammonium-grown cells. (washington.edu)
  • The multiplicity of the genes involved, the oxygen sensitivity of nitrogenase, plus the demand for energy and reducing power, are thought to be major obstacles to engineering BNF into cereal crops. (jic.ac.uk)
  • 1. Nitrogenase activity of a strain of Azotobacter chroococcum lacking the structural genes for conventional nitrogenase (nifHDK) was separated into two components: an Fe-containing protein and a vanadoprotein. (portlandpress.com)
  • In this work, studies in Rhodobacter sphaeroides firmly established that the activity of the enzyme that catalyses nitrogen fixation, nitrogenase, induces a signal that leads to repression of genes encoding enzymes of the Calvin-Benson-Bassham (CBB) CO 2 fixation pathway. (microbiologyresearch.org)
  • The fixABCX genes in Rhodospirillum rubrum encode a putative membrane complex participating in electron transfer to nitrogenase J Bacteriol 186 2052 - 2060 [View Article] [PubMed] . (microbiologyresearch.org)
  • In addition to nifH (a gene that encodes the dinitrogenase reductase component of the molybdenum nitrogenase), we also identified sequences corresponding to vanadium and iron-only nitrogenase genes. (frontiersin.org)
  • To determine which Fld and Fd proteins are relevant to nitrogenase activity, four genes proposed to play a role in electron transfer, nif F, fdx N, fdx A, and fix P, were selected and the coding region was replaced with an antibiotic resistance cassette. (boisestate.edu)
  • During unregulated-pH glucose fermentation increased H 2 production was associated with concurrent strong up-regulation of the nitrogenase coding genes. (biomedcentral.com)
  • During the fixed pH 5.2 fermentation, by contrast, the expression levels for the [FeFe] hydrogenase coding genes were higher than during the unregulated-pH fermentation, while the nitrogenase transcripts were less abundant. (biomedcentral.com)
  • In this study I used mutation analysis and gene expression studies to show that posttranslational regulation of nitrogenase activity in R. palustris depends on two proteins: DraT2, an ADP-ribosyltransferase, and GlnK2, an NtrC-regulated P(II) protein. (washington.edu)
  • Our analysis of 79,090 nitrogenase (nifH) PCR amplicons encoding 7,468 unique proteins from surface samples (ten DNA samples and two RNA samples) collected at ten marine locations world-wide provides the first in-depth survey of a functional bacterial gene and yield insights into the composition and diversity of the nifH gene pool in marine waters. (ku.dk)
  • Dingler C, Kuhla J, Wassink H, Oelze J (1988) Levels and activities of nitrogenase proteins in Azotobacter vinelandii grown at different dissolved oxygen concentrations. (springer.com)
  • Evidence is presented that the reason for the dilution effect is that one of the component proteins of nitrogenase is limiting in preparations of this enzyme. (biochemj.org)
  • Most biological nitrogen fixation is catalyzed by molybdenum-dependent nitrogenase, an enzyme complex comprising two component proteins that contains three different metalloclusters. (prolekare.cz)
  • Furthermore, the NifU and NifS protein appear to have specialized functions in the maturation of metalloclusters of nitrogenase and cannot functionally replace the isc [Fe-S] cluster system used for the maturation of other [Fe-S] proteins. (vt.edu)
  • Both proteins that make up the nitrogenase complex are irreversibly denatured by even the slightest 'sniff' of O 2 and all systems that support nitrogenase have evolved mechanisms of creating a low O 2 environment at the site of N 2 fixation. (edu.au)
  • These experiments will ultimately provide insight into the relevance of Fld and Fd proteins for electron donation to nitrogenase. (boisestate.edu)
  • Unlike molybdenum nitrogenase, vanadium nitrogenase can also reduce carbon monoxide to ethylene, ethane and propane but both enzymes can reduce protons to hydrogen gas and acetylene to ethylene. (wikipedia.org)
  • Nitrogenase enzymes catalyze the biological production of fixed nitrogen. (sciencemag.org)
  • developed a way to use nitrogenase enzymes from nitrogen-fixing bacteria to make ammonia in vitro without other biological steps or high-energy inputs. (sciencemag.org)
  • In nitrogen-fixing bacteria, the enzymatic reduction of N 2 to NH 3 is catalyzed by nitrogenase enzymes and proceeds via the hydrogenation of N 2 through metal-hydride intermediates rather than from reaction with H 2 ( 4 ). (sciencemag.org)
  • KLH -conjugated synthetic peptide derived from known bacterial NifH subunits of bacterial nitrogenase enzymes of the FeMoCo type including Synechoccocus sp. (agrisera.com)
  • Hydrogenase and nitrogenase enzymes are both capable of hydrogen production. (fao.org)
  • The build up of O 2 due to lowered respiration and higher solubility of O 2 at lower temperatures conspire to destroy nitrogenase enzymes in chilled nodules. (edu.au)
  • The trace element molybdenum is essential for nearly all organisms and forms the catalytic centre of a large variety of enzymes such as nitrogenase, nitrate reductases, sulphite oxidase and xanthine oxidoreductases. (nature.com)
  • Effect of lead on nitrogenase and enzymes of nitrogen assimilation in a cyanobacterium Nostoc muscorum. (bvsalud.org)
  • Demonstration of a molybdenum- and vanadium-independent nitrogenase in a nifHDK-deletion mutant of Rhodobacter capsulatus. (semanticscholar.org)
  • Since, in addition, malate consumption increased linearly with increasing illumination, it is proposed that light controls nitrogenase in Rhodobacter capsulatus via the C/N ratio, as represented by malate and ammonium consumption, rather than directly. (springer.com)
  • Siemann S, Schneider K, Oley M, Müller A. Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus. (uni-bielefeld.de)
  • Characterization of a tungsten-substituted nitrogenase isolated from Rhodobacter capsulatus", BIOCHEMISTRY , vol. 42, 2003, pp. 3846-3857. (uni-bielefeld.de)
  • Purified FdxN was able to mediate electron transport between illuminated chloroplasts and Rhodobacter capsulatus nitrogenase in vitro. (uni-bielefeld.de)
  • Characterization of an fdxN mutant of Rhodobacter capsulatus indicates that ferredoxin I serves as electron donor to nitrogenase. (uni-bielefeld.de)
  • VnfH adopts the same conformation that was observed for NifH, the Fe protein of molybdenum nitrogenase, in complex with ADP, representing a state of the functional cycle that is ready for reduction and subsequent nucleotide exchange. (springer.com)
  • Within the Chlorobi population, the nitrogenase ( nifH ) cluster was included in a well-structured retrotransposon. (frontiersin.org)
  • Electron transfer to nitrogenase. (portlandpress.com)
  • In contrast, an analogous ETC module from mitochondria could not function in electron transfer to nitrogenase. (jic.ac.uk)
  • On the basis of such conditions, a tungsten-substituted nitrogenase was isolated from R. capsulatus with the aid of anfA (Fe-only nitrogenase defective) mutant cells and partially purified by Q-sepharose chromatography. (uni-bielefeld.de)
  • When Azotobacter vinelandii was derepressed for nitrogenase synthesis in the presence of WO42- rather than MoO42-, it synthesized active component II and inactive component I of nitrogenase. (asm.org)
  • Characterization of mutants of these bacteria derepressed for synthesis of the nitrogenase complex in the presence of ammonium salts supports a critical role for glutamine and [lowercase alpha]-ketoglutarate in the regulation of synthesis. (umsystem.edu)
  • Jouanneau Y, Wong B, Vignais PM (1985) Stimulation by light of nitrogenase synthesis in cells of Rhodopseudomonas capsulata growing in N-limited continuous cultures. (springer.com)
  • The minimal nif gene cluster enables synthesis of catalytically active nitrogenase in this host, when expressed either from the native nifB promoter or from the T7 promoter. (prolekare.cz)
  • Synthesis of Nitrogenase in the Cyanobacterium Gloeothece (Gloeocapsa) sp. (microbiologyresearch.org)
  • 55 FeCI 3 labelling and non-denaturing gel electrophoresis were used to study nitrogenase synthesis in Gloeothece sp. (microbiologyresearch.org)
  • Upon transfer of cultures of Gloeothece from light to darkness, there was initially a slight decrease in the rate of synthesis of nitrogenase but after 4-5 h there was an almost complete cessation of synthesis. (microbiologyresearch.org)
  • This delayed effect of darkness on nitrogenase synthesis could not be related to any change in RNA synthesis, in protein synthesis or in the rate of breakdown of storage glucan. (microbiologyresearch.org)
  • If darkness exerts its effect on nitrogenase synthesis by inhibiting the synthesis of nif mRNA, it does so only after a lag of about 4 h. (microbiologyresearch.org)
  • During cell growth under Mo-deficient conditions, tungstate, at high concentrations (I mM), was capable of partially (similar to25%) substituting for molybdate in the induction of nitrogenase synthesis. (uni-bielefeld.de)
  • Vanadium nitrogenase and iron-only nitrogenase can both be found in select species of Azotobacter as an alternative nitrogenase. (wikipedia.org)
  • Nitrogenase is an enzyme responsible for catalyzing nitrogen fixation, which is the reduction of nitrogen (N2) to ammonia (NH3) and a process vital to sustaining life on Earth. (wikipedia.org)
  • The results reported herein contribute to ongoing efforts of mimicking nitrogenase in fixing nitrogen and point to a promising path in developing catalysts for the reduction of N 2 under ambient conditions. (pnas.org)
  • Corn ( Zea mays L.) plants were assayed for nitrogenase activity (C 2 H 2 reduction) during early ear development. (plantphysiol.org)
  • The time course of C 2 H 2 reduction by excised roots, assayed in air, was similar for all genotypes studied (two hybrids, eight inbreds, and a cross of corn × teosinte) and indicated that a long preincubation at reduced O 2 is not absolutely required for early detection of nitrogenase activity. (plantphysiol.org)
  • The requirement for molybdenum in biological dinitrogen fixation, first reported by Bortels1, is due to its involvement at or near the site of reduction of N2 in conventional nitrogenase. (semanticscholar.org)
  • The nitrogenase system from Azotobacter: two-enzyme requirement for N2 reduction, ATP-dependent H2 evolution, and ATP hydrolysis. (semanticscholar.org)
  • In the Haber-Bosch process, N 2 reduction is accomplished at high temperature and pressure, whereas N 2 fixation by the enzyme nitrogenase occurs under ambient conditions using chemical energy from adenosine 5′-triphosphate (ATP) hydrolysis. (sciencemag.org)
  • Inhibitors of nitrogenase (i.e., acetylene, carbon monoxide, and dihydrogen) suppressed N 2 reduction. (sciencemag.org)
  • Nitrogenase catalyzes the biological reduction of N2 to ammonia (nitrogen fixation). (vt.edu)
  • Nitrogenase is the only enzyme known to catalyze the reduction of N2 to 2NH3. (semanticscholar.org)
  • Our data show that exogenously applied BMAA rapidly inhibits nitrogenase activity (acetylene reduction assay), even at micromolar concentrations, and that the inhibition was considerably more severe than that induced by combined nitrogen sources and most other amino acids. (mdpi.com)
  • The enzyme committed to this task, nitrogenase, orchestrates an elegant unidirectional multiple electron reduction and activation of the nitrogen triple bond. (montana.edu)
  • Additionally, nitrogenase activity will be measured with whole cell acetylene reduction assays using gas chromatography. (boisestate.edu)
  • Little is known about substrate binding and reduction of nitrogenase. (lsu.edu)
  • Nitrogenase catalyzes the conversion of dinitrogen gas (N2) and protons to ammonia and hydrogen gas (H2). (washington.edu)
  • Nitrogenase bioelectrocatalysis: heterogeneous ammonia and hydrogen pr" by Ross D. Milton, Sofiene Abdellaoui et al. (usu.edu)
  • RbrA, a cyanobacterial rubrerythrin, functions as a FNR-dependent peroxidase in heterocysts in protection of nitrogenase from damage by hydrogen peroxide in Anabaena sp. (semanticscholar.org)
  • Aerobic Hydrogen Production via Nitrogenase in Azotobacter vinelandii CA6. (uni-bielefeld.de)
  • The project is focused in fundamental and applied research activities to study the assembly of nitrogenase and optimize hydrogen-producing capability of this enzyme. (imdea.org)
  • Nitrogenase: bacterial protein which produces ammonia and hydrogen. (imdea.org)
  • By contrast, nitrogenase-mediated hydrogen production has never been proposed for clostridia, even though this is known to be an intrinsic metabolic property of many cyanobacteria and photosynthetic bacteria [ 2 ]. (biomedcentral.com)
  • The coupling of ATP hydrolysis to electron transfer by the enzyme nitrogenase during biological nitrogen fixation is an important example of a nucleotide-dependent transduction mechanism. (nih.gov)
  • Bioelectroreduction of nitrogen to ammonia: the incorporation of nitrogenase within enzymatic biological fuel cells for simultaneous production of electrical energy and ammonia. (europa.eu)
  • Light-activated CdS nanorods provided electrons to the FeMo nitrogenase enzyme to reduce nitrogen and produce ammonia at rates up to 64% of biological nitrogen fixation. (sciencemag.org)
  • The Molybdenum-nitrogenase is responsible for most biological nitrogen fixation activity (BNF) in the biosphere. (upm.es)
  • Understanding the mechanistic details of biological nitrogen fixation catalyzed by the enzyme nitrogenase would be beneficial both for designing cleaner or more efficient catalysts for small molecule activation and for understanding biological multi-electron/proton redox processes. (escholarship.org)
  • Most biological nitrogen fixation is catalyzed by molybdenum-dependent nitrogenase, which is distributed within bacteria and archaea. (peerj.com)
  • Through the biological fixation of the element nitrogen by the enzyme nitrogenase, organisms gain access to molecular nitrogen in the Earth's atmosphere, which is essential for building cellular structures. (newstimes.top)
  • [11] Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by a nitrogenase enzyme. (wikipedia.org)
  • The role of nucleotide binding and hydrolysis in nitrogenase catalysis is one of the most fascinating aspects of nitrogenase function. (montana.edu)
  • Temperature invariance of the nitrogenase electron transfer mechanism. (sigmaaldrich.com)
  • This is of probable importance for the nitrogenase mechanism. (diva-portal.org)
  • The Fe protein upon binding to MgATP undergoes a huge conformational change which is important for subsequent steps of nitrogenase reaction mechanism. (montana.edu)
  • Recent spectroscopic work on iron- molybdenum nitrogenase strongly suggests that the mechanism involves binding of N2 to iron, and involves iron-hydride species. (grantome.com)
  • This mechanism for exquisite adaptation to extreme O 2 levels, and ability to express nitrogenase at very high pO 2 , only became clear by using some interesting optical techniques. (edu.au)
  • Mckenna, Charles E. / Perspectives on the mechanism of ATP hydrolysis by nitrogenase . (elsevier.com)
  • Burgess, B. K. & Lowe, D. J. Mechanism of molybdenum nitrogenase. (nature.com)
  • Molybdenum nitrogenase, which can be found in diazotrophs such as legume-associated rhizobia, is the nitrogenase that has been studied the most extensively and thus is the most well characterized. (wikipedia.org)
  • Such conversion is catalyzed by nitrogenase, an enzyme produced by a select group of microorganisms called diazotrophs. (pnas.org)
  • In general high application of N negatively affected the nitrogenase activity, diazotrophs colonization on rice roots, photosynthesis and plant growth. (thefreelibrary.com)
  • Mo-nitrogenase is found in all diazotrophs, and its expression is regulated by Mo concentration. (frontiersin.org)
  • [13] In free-living diazotrophs , nitrogenase-generated ammonia is assimilated into glutamate through the glutamine synthetase /glutamate synthase pathway. (wikipedia.org)
  • The X-ray crystal structure of Klebsiella pneumoniae nitrogenase component 1 (Kp1) has been determined and refined to a resolution of 1.6 A, the highest resolution reported for any nitrogenase structure. (rcsb.org)
  • The molybdenum-iron protein of Klebsiella pneumoniae nitrogenase. (portlandpress.com)
  • Nitrogenase of Klebsiella pneumoniae. (semanticscholar.org)
  • However, the nitrogenase activity of the hesA mutant could not be restored by Klebsiella oxytoca nifQ or Escherichia coli moeB completely. (peerj.com)
  • Structure predictions and surface charge of nitrogenase flavodoxins from Klebsiella pneumoniae and Azotobacter vinelandii. (semanticscholar.org)
  • The binding sites of Iron atom in the structure of Nitrogenase Iron Protein From Clostridium Pasteurianum (pdb code 1cp2 ). (atomistry.com)
  • The Anf nitrogenase in Azotobacter vinelandii is organized in an anfHDGKOR operon. (wikipedia.org)
  • Figures 1-2 display the crystal structure and key catalytic components of molybdenum nitrogenase extracted from Azotobacter vinelandii. (wikipedia.org)
  • Here we present the 2.2 Å resolution structure of VnfH from Azotobacter vinelandii , the Fe protein of the alternative, vanadium-dependent nitrogenase system, in its ADP-bound state. (springer.com)
  • Effects of homocitrate, homocitrate lactone, and fluorohomocitrate on nitrogenase in NifV- mutants of Azotobacter vinelandii. (semanticscholar.org)
  • Jouanneau Y, Lebeque S, Vignais PM (1984) Ammonia and light effect on nitrogenase activity in nitrogen-limited continuous cultures of Rhodopseudomonas capsulata . (springer.com)
  • Mutant studies have evidenced that the activity of the nitrogenase FeMo-co is significantly influenced by the environment. (ct-si.org)
  • Transcriptional regulation of V-nitrogenase in R. palustris is poorly understood and I have isolated and described a mutant which expresses V-nitrogenase constitutively. (washington.edu)
  • The limiting component appears to be the non-haem-iron-containing protein (also called fraction II, iron protein, azoferredoxin), which is equivalent to the enhancement factor for nitrogenase activity present in extracts of nitrogenaseless mutant 22R1. (biochemj.org)
  • Nitrogenase activity was low in the mutant, whereas exogenous iron and expression of wild-type MtNramp1 in mutant nodules increased nitrogen fixation to normal levels. (plantphysiol.org)
  • There are three types of nitrogenase found in various nitrogen-fixing bacteria: molybdenum (Mo) nitrogenase, vanadium (V) nitrogenase, and iron-only (Fe) nitrogenase. (wikipedia.org)
  • We observe that the FNR-ferredoxin module from chloroplasts and root plastids can support the activities of both types of nitrogenase. (jic.ac.uk)
  • Thus, nitrogenase is not normally expressed or active in bacteria grown with a readily utilized nitrogen source like ammonium. (washington.edu)
  • GlnK2 was not well expressed in ammonium-grown NifA* cells and thus not available to activate the DraT2 nitrogenase modification enzyme. (washington.edu)
  • Inactivation of the nitrogenase posttranslational modification system by a draT2 mutation resulted in increased H2 production by ammonium-grown NifA* cells. (washington.edu)
  • 1997). It is the process in which N2 is reduced to ammonium (NH4+) by nitrogenase enzyme.The isolation and identification of N2 fixing bacteria in rice fields has been well documented over the past two decades (Xie et al. (thefreelibrary.com)
  • Compared to Mo nitrogenase, V nitrogenase replaces one sulfide in the active site with a bridging ligand. (wikipedia.org)
  • Nitrogenase acts as a catalyst, reducing this energy barrier such that the reaction can take place at ambient temperatures. (wikipedia.org)
  • Researchers are seeking to better understand how nitrogenase acts as a catalyst to break down nitrogen. (pnnl.gov)
  • We pinpoint endogenous ETCs from plant organelles as power supplies to support nitrogenase for future engineering of diazotrophy in cereal crops. (jic.ac.uk)
  • 0.05) for nitrogenase activity in bacterial tubes, the difference for nitrogenase activity of co-inoculated plants with combination of Sp7 and Rhizobium either standard or native were significantly different. (mysciencework.com)
  • The free-energy transformations that occur in nitrogenase based upon theoretical analysis of structural and electrochemical data is described using electrostatic and thermodynamic analysis. (readabstracts.com)
  • In addition, a vanadium-dependent variant of nitrogenase can reduce the toxic gas carbon monoxide to hydrocarbons. (newstimes.top)
  • Most of the functions of vanadium nitrogenase match those of the more common molybdenum nitrogenases and serve as an alternative pathway for nitrogen fixation in molybdenum deficient conditions. (wikipedia.org)
  • At room temperature, vanadium nitrogenase is less efficient at fixing nitrogen than molybdenum nitrogenases because it converts more H+ to H2 as a side reaction. (wikipedia.org)
  • However, at low temperatures vanadium nitrogenases have been found to be more active than the molybdenum type, and at temperatures as low as 5 °C its nitrogen-fixing activity is 10 times higher than that of molybdenum nitrogenase. (wikipedia.org)
  • Three nitrogenases co-exist in nature: molybdenum-iron (Mo-nitrogenase), vanadium-iron, and iron-only (Fe-only nitrogenase). (frontiersin.org)
  • Atmospheric nitrogen fixation is a tremendous chemical feat accomplished by a few select microorganisms possessing nitrogenase, a unique metalloenzyme. (grantome.com)
  • Vanadium-iron nitrogenase is present in some microorganisms and may be expressed when Mo is scarce. (frontiersin.org)
  • In field and pot experiments the effect of selected pesticides on the nitrogenase activity, num-ber of soil microorganisms, and yield of hybrid lucerne was investigated. (pjoes.com)
  • Like molybdenum nitrogenase, dihydrogen functions as a competitive inhibitor and carbon monoxide functions as a non-competitive inhibitor of nitrogen fixation. (wikipedia.org)
  • Nitrogenase is a complex metal-containing enzyme that catalyzes the conversion of nitrogen gas to ammonia. (montana.edu)
  • This molybdenum-iron protein is part of the nitrogenase complex that catalyzes the key enzymatic reactions in nitrogen fixation. (icr.ac.uk)
  • The enzyme that catalyzes all this is nitrogenase, and it does it by breaking one of the strongest bonds in chemistry - the nitrogen triple bond. (redorbit.com)
  • Ribet, J. and Drevon, J.-J. (1995) Phosphorus Deficiency Increases the Acetylene-Induced Decline in Nitrogenase Activity in Soybean (Glycine max (L.) Merr. (scirp.org)
  • Inactivation of NifU or NifS has been shown to affect the activity of both nitrogenase components. (vt.edu)
  • This increase could lead to O 2 inactivation of nitrogenase. (umn.edu)
  • Mo-nitrogenase is the enzyme responsible for the conversion of atmospheric nitrogen to ammonia. (ct-si.org)
  • The key enzymatic reactions in nitrogen fixation are catalyzed by the nitrogenase complex, which has 2 components: the iron protein (component 2) and a component 1 which is either a molybdenum-iron protein, a vanadium-iron, or an iron-iron protein. (uniprot.org)
  • Structure of ADP x AIF4(-)-stabilized nitrogenase complex and its implications for signal transduction. (nih.gov)
  • Interactions in the nitrogenase complex have broad implications for signal and energy transduction mechanisms in multiprotein complexes. (nih.gov)
  • The turnover rate was 75 per minute, 63% of the ATP-coupled reaction rate for the nitrogenase complex under optimal conditions. (sciencemag.org)
  • 12 International Conference on Bioinorganic Chemistry (ICBIC-12) Newton, W. E. Some Insights into How Nitrogenase Works Menck, E. Mossbauer and EPR Studies of Nitrogenase Holm, R. H. Chemical Approaches to Complex Heterometalsulfur Sites in Biology Pickett, C. Interactions of small molecules at isolated Fe. (present5.com)
  • Forms complex with the iron protein (nitrogenase component 2). (icr.ac.uk)
  • Nitrogenase is an oxygen sensitive, complex two-component enzyme that is mechanistically pertinent to many other biochemical processes. (montana.edu)
  • Like a shadowy character just hidden from view, a mystery atom in the middle of a complex enzyme called nitrogenase had long hindered scientists' ability to study the enzyme fully. (redorbit.com)
  • Structure of ADP·AIF4 − -stabilized nitrogenase complex and its implications for signal transduction. (nature.com)
  • It is carried out by prokaryotes using an enzyme complex called nitrogenase and results in atmospheric N2 being reduced into a form of nitrogen diazotrophic organisms and plants are able to use (ammonia). (wiley.com)
  • How Does the DraG-P II Complex Regulate Nitrogenase Activity in Azospirillum brasilense ? (wiley.com)
  • An explanation of these results and their relation to possible models for the regulation of nitrogenase is given. (asm.org)
  • Kanemoto RH, Ludden PW (1984) Effect of ammonia, darkness, and phenazine methosulfate on whole-cell nitrogenase activity ER, Chock PB, Levitzki A (eds) Current topics in cellular regulation, vol 30. (springer.com)
  • Vanadium nitrogenase is a key enzyme for nitrogen fixation found in nitrogen-fixing bacteria, and is used as an alternative to molybdenum nitrogenase when molybdenum is unavailable. (wikipedia.org)