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  1 / 2286 MEDLINE  
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[PMID]:27775698
[Au] Autor:König S; Gros O; Heiden SE; Hinzke T; Thürmer A; Poehlein A; Meyer S; Vatin M; Mbéguié-A-Mbéguié D; Tocny J; Ponnudurai R; Daniel R; Becher D; Schweder T; Markert S
[Ad] Endereço:Department of Pharmaceutical Biotechnology, E.M.A. University of Greifswald, Institute of Pharmacy, Greifswald, Germany.
[Ti] Título:Nitrogen fixation in a chemoautotrophic lucinid symbiosis.
[So] Source:Nat Microbiol;2:16193, 2016 Oct 24.
[Is] ISSN:2058-5276
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The shallow water bivalve Codakia orbicularis lives in symbiotic association with a sulfur-oxidizing bacterium in its gills. The endosymbiont fixes CO and thus generates organic carbon compounds, which support the host's growth. To investigate the uncultured symbiont's metabolism and symbiont-host interactions in detail we conducted a proteogenomic analysis of purified bacteria. Unexpectedly, our results reveal a hitherto completely unrecognized feature of the C. orbicularis symbiont's physiology: the symbiont's genome encodes all proteins necessary for biological nitrogen fixation (diazotrophy). Expression of the respective genes under standard ambient conditions was confirmed by proteomics. Nitrogenase activity in the symbiont was also verified by enzyme activity assays. Phylogenetic analysis of the bacterial nitrogenase reductase NifH revealed the symbiont's close relationship to free-living nitrogen-fixing Proteobacteria from the seagrass sediment. The C. orbicularis symbiont, here tentatively named 'Candidatus Thiodiazotropha endolucinida', may thus not only sustain the bivalve's carbon demands. C. orbicularis may also benefit from a steady supply of fixed nitrogen from its symbiont-a scenario that is unprecedented in comparable chemoautotrophic symbioses.
[Mh] Termos MeSH primário: Bivalves/microbiologia
Crescimento Quimioautotrófico
Gammaproteobacteria/fisiologia
Fixação de Nitrogênio
Simbiose
[Mh] Termos MeSH secundário: Animais
Gammaproteobacteria/química
Gammaproteobacteria/genética
Gammaproteobacteria/metabolismo
Brânquias/microbiologia
Redes e Vias Metabólicas/genética
Nitrogenase/metabolismo
Oxirredutases/genética
Filogenia
Proteoma/análise
Análise de Sequência de DNA
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Proteome); EC 1.- (Oxidoreductases); EC 1.18.6.1 (Nitrogenase); EC 1.18.6.1 (nitrogenase reductase)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180126
[Lr] Data última revisão:
180126
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE
[do] DOI:10.1038/nmicrobiol.2016.193


  2 / 2286 MEDLINE  
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[PMID]:27775707
[Au] Autor:Petersen JM; Kemper A; Gruber-Vodicka H; Cardini U; van der Geest M; Kleiner M; Bulgheresi S; Mußmann M; Herbold C; Seah BK; Antony CP; Liu D; Belitz A; Weber M
[Ad] Endereço:Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria.
[Ti] Título:Chemosynthetic symbionts of marine invertebrate animals are capable of nitrogen fixation.
[So] Source:Nat Microbiol;2:16195, 2016 Oct 24.
[Is] ISSN:2058-5276
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Chemosynthetic symbioses are partnerships between invertebrate animals and chemosynthetic bacteria. The latter are the primary producers, providing most of the organic carbon needed for the animal host's nutrition. We sequenced genomes of the chemosynthetic symbionts from the lucinid bivalve Loripes lucinalis and the stilbonematid nematode Laxus oneistus. The symbionts of both host species encoded nitrogen fixation genes. This is remarkable as no marine chemosynthetic symbiont was previously known to be capable of nitrogen fixation. We detected nitrogenase expression by the symbionts of lucinid clams at the transcriptomic and proteomic level. Mean stable nitrogen isotope values of Loripes lucinalis were within the range expected for fixed atmospheric nitrogen, further suggesting active nitrogen fixation by the symbionts. The ability to fix nitrogen may be widespread among chemosynthetic symbioses in oligotrophic habitats, where nitrogen availability often limits primary productivity.
[Mh] Termos MeSH primário: Organismos Aquáticos/microbiologia
Bactérias/enzimologia
Bivalves/microbiologia
Cromadoria/microbiologia
Fixação de Nitrogênio
Simbiose
[Mh] Termos MeSH secundário: Animais
Bactérias/genética
Perfilação da Expressão Gênica
Nitrogenase/genética
Proteoma/análise
Análise de Sequência de DNA
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Proteome); EC 1.18.6.1 (Nitrogenase)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180126
[Lr] Data última revisão:
180126
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE
[do] DOI:10.1038/nmicrobiol.2016.195


  3 / 2286 MEDLINE  
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[PMID]:28450383
[Au] Autor:Hong H; Shen R; Zhang F; Wen Z; Chang S; Lin W; Kranz SA; Luo YW; Kao SJ; Morel FMM; Shi D
[Ad] Endereço:State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, P.R. China.
[Ti] Título:The complex effects of ocean acidification on the prominent N -fixing cyanobacterium .
[So] Source:Science;356(6337):527-531, 2017 05 05.
[Is] ISSN:1095-9203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Acidification of seawater caused by anthropogenic carbon dioxide (CO ) is anticipated to influence the growth of dinitrogen (N )-fixing phytoplankton, which contribute a large fraction of primary production in the tropical and subtropical ocean. We found that growth and N -fixation of the ubiquitous cyanobacterium decreased under acidified conditions, notwithstanding a beneficial effect of high CO Acidification resulted in low cytosolic pH and reduced N -fixation rates despite elevated nitrogenase concentrations. Low cytosolic pH required increased proton pumping across the thylakoid membrane and elevated adenosine triphosphate production. These requirements were not satisfied under field or experimental iron-limiting conditions, which greatly amplified the negative effect of acidification.
[Mh] Termos MeSH primário: Fixação de Nitrogênio
Nitrogênio/metabolismo
Água do Mar/química
Água do Mar/microbiologia
Trichodesmium/crescimento & desenvolvimento
Trichodesmium/metabolismo
[Mh] Termos MeSH secundário: Dióxido de Carbono/metabolismo
Concentração de Íons de Hidrogênio
Ferro/deficiência
Nitrogenase/metabolismo
Oceanos e Mares
Bombas de Próton/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Proton Pumps); 142M471B3J (Carbon Dioxide); E1UOL152H7 (Iron); EC 1.18.6.1 (Nitrogenase); N762921K75 (Nitrogen)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180117
[Lr] Data última revisão:
180117
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170429
[St] Status:MEDLINE
[do] DOI:10.1126/science.aal2981


  4 / 2286 MEDLINE  
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[PMID]:28784660
[Au] Autor:Pence N; Tokmina-Lukaszewska M; Yang ZY; Ledbetter RN; Seefeldt LC; Bothner B; Peters JW
[Ad] Endereço:From the Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164.
[Ti] Título:Unraveling the interactions of the physiological reductant flavodoxin with the different conformations of the Fe protein in the nitrogenase cycle.
[So] Source:J Biol Chem;292(38):15661-15669, 2017 Sep 22.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Nitrogenase reduces dinitrogen (N ) to ammonia in biological nitrogen fixation. The nitrogenase Fe protein cycle involves a transient association between the reduced, MgATP-bound Fe protein and the MoFe protein and includes electron transfer, ATP hydrolysis, release of P , and dissociation of the oxidized, MgADP-bound Fe protein from the MoFe protein. The cycle is completed by reduction of oxidized Fe protein and nucleotide exchange. Recently, a kinetic study of the nitrogenase Fe protein cycle involving the physiological reductant flavodoxin reported a major revision of the rate-limiting step from MoFe protein and Fe protein dissociation to release of P Because the Fe protein cannot interact with flavodoxin and the MoFe protein simultaneously, knowledge of the interactions between flavodoxin and the different nucleotide states of the Fe protein is critically important for understanding the Fe protein cycle. Here we used time-resolved limited proteolysis and chemical cross-linking to examine nucleotide-induced structural changes in the Fe protein and their effects on interactions with flavodoxin. Differences in proteolytic cleavage patterns and chemical cross-linking patterns were consistent with known nucleotide-induced structural differences in the Fe protein and indicated that MgATP-bound Fe protein resembles the structure of the Fe protein in the stabilized nitrogenase complex structures. Docking models and cross-linking patterns between the Fe protein and flavodoxin revealed that the MgADP-bound state of the Fe protein has the most complementary docking interface with flavodoxin compared with the MgATP-bound state. Together, these findings provide new insights into the control mechanisms in protein-protein interactions during the Fe protein cycle.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Proteínas de Bactérias/metabolismo
Flavodoxina/metabolismo
Ferro/metabolismo
Nitrogenase/metabolismo
Substâncias Redutoras/metabolismo
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Azotobacter vinelandii/enzimologia
Simulação de Acoplamento Molecular
Nitrogenase/química
Ligação Proteica
Conformação Proteica
Proteólise
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Flavodoxin); 0 (Reducing Agents); E1UOL152H7 (Iron); EC 1.18.6.1 (Nitrogenase)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171009
[Lr] Data última revisão:
171009
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170809
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M117.801548


  5 / 2286 MEDLINE  
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[PMID]:28710816
[Au] Autor:Segal HM; Spatzal T; Hill MG; Udit AK; Rees DC
[Ad] Endereço:Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, 91125.
[Ti] Título:Electrochemical and structural characterization of Azotobacter vinelandii flavodoxin II.
[So] Source:Protein Sci;26(10):1984-1993, 2017 Oct.
[Is] ISSN:1469-896X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Azotobacter vinelandii flavodoxin II serves as a physiological reductant of nitrogenase, the enzyme system mediating biological nitrogen fixation. Wildtype A. vinelandii flavodoxin II was electrochemically and crystallographically characterized to better understand the molecular basis for this functional role. The redox properties were monitored on surfactant-modified basal plane graphite electrodes, with two distinct redox couples measured by cyclic voltammetry corresponding to reduction potentials of -483 ± 1 mV and -187 ± 9 mV (vs. NHE) in 50 mM potassium phosphate, 150 mM NaCl, pH 7.5. These redox potentials were assigned as the semiquinone/hydroquinone couple and the quinone/semiquinone couple, respectively. This study constitutes one of the first applications of surfactant-modified basal plane graphite electrodes to characterize the redox properties of a flavodoxin, thus providing a novel electrochemical method to study this class of protein. The X-ray crystal structure of the flavodoxin purified from A. vinelandii was solved at 1.17 Å resolution. With this structure, the native nitrogenase electron transfer proteins have all been structurally characterized. Docking studies indicate that a common binding site surrounding the Fe-protein [4Fe:4S] cluster mediates complex formation with the redox partners Mo-Fe protein, ferredoxin I, and flavodoxin II. This model supports a mechanistic hypothesis that electron transfer reactions between the Fe-protein and its redox partners are mutually exclusive.
[Mh] Termos MeSH primário: Azotobacter vinelandii/química
Proteínas de Bactérias/química
Proteínas de Bactérias/metabolismo
Flavodoxina/química
Flavodoxina/metabolismo
[Mh] Termos MeSH secundário: Azotobacter vinelandii/metabolismo
Azotobacter vinelandii/fisiologia
Cristalografia por Raios X
Eletroquímica
Concentração de Íons de Hidrogênio
Ferro/química
Ferro/metabolismo
Modelos Moleculares
Nitrogenase
Conformação Proteica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Flavodoxin); E1UOL152H7 (Iron); EC 1.18.6.1 (Nitrogenase)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170716
[St] Status:MEDLINE
[do] DOI:10.1002/pro.3236


  6 / 2286 MEDLINE  
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[PMID]:28704608
[Au] Autor:Ledbetter RN; Garcia Costas AM; Lubner CE; Mulder DW; Tokmina-Lukaszewska M; Artz JH; Patterson A; Magnuson TS; Jay ZJ; Duan HD; Miller J; Plunkett MH; Hoben JP; Barney BM; Carlson RP; Miller AF; Bothner B; King PW; Peters JW; Seefeldt LC
[Ad] Endereço:Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322, United States.
[Ti] Título:The Electron Bifurcating FixABCX Protein Complex from Azotobacter vinelandii: Generation of Low-Potential Reducing Equivalents for Nitrogenase Catalysis.
[So] Source:Biochemistry;56(32):4177-4190, 2017 Aug 15.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The biological reduction of dinitrogen (N ) to ammonia (NH ) by nitrogenase is an energetically demanding reaction that requires low-potential electrons and ATP; however, pathways used to deliver the electrons from central metabolism to the reductants of nitrogenase, ferredoxin or flavodoxin, remain unknown for many diazotrophic microbes. The FixABCX protein complex has been proposed to reduce flavodoxin or ferredoxin using NADH as the electron donor in a process known as electron bifurcation. Herein, the FixABCX complex from Azotobacter vinelandii was purified and demonstrated to catalyze an electron bifurcation reaction: oxidation of NADH (E = -320 mV) coupled to reduction of flavodoxin semiquinone (E = -460 mV) and reduction of coenzyme Q (E = 10 mV). Knocking out fix genes rendered Δrnf A. vinelandii cells unable to fix dinitrogen, confirming that the FixABCX system provides another route for delivery of electrons to nitrogenase. Characterization of the purified FixABCX complex revealed the presence of flavin and iron-sulfur cofactors confirmed by native mass spectrometry, electron paramagnetic resonance spectroscopy, and transient absorption spectroscopy. Transient absorption spectroscopy further established the presence of a short-lived flavin semiquinone radical, suggesting that a thermodynamically unstable flavin semiquinone may participate as an intermediate in the transfer of an electron to flavodoxin. A structural model of FixABCX, generated using chemical cross-linking in conjunction with homology modeling, revealed plausible electron transfer pathways to both high- and low-potential acceptors. Overall, this study informs a mechanism for electron bifurcation, offering insight into a unique method for delivery of low-potential electrons required for energy-intensive biochemical conversions.
[Mh] Termos MeSH primário: Azotobacter vinelandii/enzimologia
Modelos Moleculares
Complexos Multienzimáticos/química
Nitrogenase/química
[Mh] Termos MeSH secundário: Catálise
Transporte de Elétrons/fisiologia
Complexos Multienzimáticos/genética
Complexos Multienzimáticos/metabolismo
Nitrogenase/genética
Nitrogenase/metabolismo
Estrutura Quaternária de Proteína
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Multienzyme Complexes); EC 1.18.6.1 (Nitrogenase)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170817
[Lr] Data última revisão:
170817
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170714
[St] Status:MEDLINE
[do] DOI:10.1021/acs.biochem.7b00389


  7 / 2286 MEDLINE  
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[PMID]:28692069
[Au] Autor:Sippel D; Einsle O
[Ad] Endereço:Lehrstuhl Biochemie, Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg Research Institute for Advanced Studies (FRIAS), and BIOSS Centre for Biological Signalling Studies, Freiburg, Germany.
[Ti] Título:The structure of vanadium nitrogenase reveals an unusual bridging ligand.
[So] Source:Nat Chem Biol;13(9):956-960, 2017 Sep.
[Is] ISSN:1552-4469
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Nitrogenases catalyze the reduction of dinitrogen (N ) gas to ammonium at a complex heterometallic cofactor. This most commonly occurs at the FeMo cofactor (FeMoco), a [Mo-7Fe-9S-C] cluster whose exact reactivity and substrate-binding mode remain unknown. Alternative nitrogenases replace molybdenum with either vanadium or iron and differ in reactivity, most prominently in the ability of vanadium nitrogenase to reduce CO to hydrocarbons. Here we report the 1.35-Å structure of vanadium nitrogenase from Azotobacter vinelandii. The 240-kDa protein contains an additional α-helical subunit that is not present in molybdenum nitrogenase. The FeV cofactor (FeVco) is a [V-7Fe-8S-C] cluster with a homocitrate ligand to vanadium. Unexpectedly, it lacks one sulfide ion compared to FeMoco, which is replaced by a bridging ligand, likely a µ-1,3-carbonate. The anion fits into a pocket within the protein that is obstructed in molybdenum nitrogenase, and its different chemical character helps to rationalize the altered chemical properties of this unique N - and CO-fixing enzyme.
[Mh] Termos MeSH primário: Modelos Moleculares
Nitrogenase/química
[Mh] Termos MeSH secundário: Azotobacter vinelandii/enzimologia
Carbonatos/química
Ligantes
Molibdoferredoxina/química
Oxirredução
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Carbonates); 0 (Ligands); 0 (Molybdoferredoxin); EC 1.18.6.1 (Nitrogenase)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170908
[Lr] Data última revisão:
170908
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170711
[St] Status:MEDLINE
[do] DOI:10.1038/nchembio.2428


  8 / 2286 MEDLINE  
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[PMID]:28121619
[Au] Autor:Danial AW; Abdel Wahab AM; Arafat HH; Abdel-Basset R
[Ti] Título:Bioenergetics of lactate vs. acetate outside TCA enhanced the hydrogen evolution levels in two newly isolated strains of the photosynthetic bacterium Rhodopseudomonas.
[So] Source:Z Naturforsch C;72(3-4):99-105, 2017 Mar 01.
[Is] ISSN:0939-5075
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Two local hydrogen-evolving strains of purple nonsulfur bacteria have been isolated, characterized, and identified as Rhodopseudomonas sp. TUT (strains Rh1 and Rh2). Lactate followed by succinate and malate supported the highest amounts of H2 production, growth (O.D.660nm, proteins and bacteriochlorphyll contents), nitrogenase activity, and uptake hydrogenase; the least of which was acetate. Alginate-immobilized cells evolved higher hydrogen amounts than free cell counterparts. Rh1 was more productive than Rh2 at all circumstances. Lactate-dependent hydrogen evolution was more than twice that of acetate, due to ATP productivity (2/-1, respectively), which is limiting to the nitrogenase activity. The preference of lactate over other acids indicates the feasibility of using these two strains in hydrogen production from dairy wastewater.
[Mh] Termos MeSH primário: Ácido Acético/farmacologia
Células Imobilizadas/efeitos dos fármacos
Metabolismo Energético
Hidrogênio/metabolismo
Ácido Láctico/farmacologia
Rodopseudomonas/efeitos dos fármacos
[Mh] Termos MeSH secundário: Ácido Acético/metabolismo
Trifosfato de Adenosina/metabolismo
Alginatos/química
Bacterioclorofilas/biossíntese
Células Imobilizadas/metabolismo
Ácido Glucurônico/química
Ácidos Hexurônicos/química
Hidrogenase/biossíntese
Cinética
Ácido Láctico/metabolismo
Malatos/metabolismo
Malatos/farmacologia
Nitrogenase/biossíntese
Fotossíntese/fisiologia
Rodopseudomonas/metabolismo
Ácido Succínico/metabolismo
Ácido Succínico/farmacologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Alginates); 0 (Bacteriochlorophylls); 0 (Hexuronic Acids); 0 (Malates); 33X04XA5AT (Lactic Acid); 7YNJ3PO35Z (Hydrogen); 817L1N4CKP (malic acid); 8A5D83Q4RW (Glucuronic Acid); 8C3Z4148WZ (alginic acid); 8L70Q75FXE (Adenosine Triphosphate); AB6MNQ6J6L (Succinic Acid); EC 1.12.7.2 (Hydrogenase); EC 1.18.6.1 (Nitrogenase); Q40Q9N063P (Acetic Acid)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171103
[Lr] Data última revisão:
171103
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170126
[St] Status:MEDLINE


  9 / 2286 MEDLINE  
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[PMID]:28104568
[Au] Autor:Dance I
[Ad] Endereço:School of Chemistry, UNSW Australia, Sydney, 2052, Australia. Electronic address: i.dance@unsw.edu.au.
[Ti] Título:New insights into the reaction capabilities of His adjacent to the active site of nitrogenase.
[So] Source:J Inorg Biochem;169:32-43, 2017 Apr.
[Is] ISSN:1873-3344
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The active site of the enzyme nitrogenase is the FeMo-cofactor (FeMo-co), a C-centred Fe MoS cluster, connected to the surrounding MoFe protein via ligands Cys and His . Density functional calculations, involving 14 additional surrounding amino acids, focus on His because its mutation causes important reactivity changes, including almost complete loss of ability to reduce N to NH . The Nε side-chain of His is capable of hydrogen bonding to S2B, bridging Fe2 and Fe6 of FeMo-co, believed to be the main reaction domain of nitrogenase. Details are presented for the possible ways in which protonated or deprotonated Nε of His interact with S2B or S2B-H or Fe2 or Fe2-H or Fe-(H ). Movements of the His side-chain allow formation of a significant short dihydrogen bond between Nε of His and H on Fe2: Nε-H••H-Fe2, with H-H=1.39Å. It is shown that a 180° rotation of the imidazole ring of His is not able to facilitate transfer of protons from the protein surface to FeMo-co. His is able to move H atoms to and from S2B, and the characteristics of H transfer between S2B and Nε of His are described, together with their dependence on the protonation state of His and the redox state of FeMo-co. The water molecule on the posterior Nδ side of His can mediate proton transfer to and from the side-chain of Tyr . The accumulated results suggest that protonated His could be the agent for the first, most difficult, transfer of H to bound substrate N .
[Mh] Termos MeSH primário: Histamina/química
Molibdoferredoxina/química
Molibdoferredoxina/metabolismo
Nitrogenase/química
Nitrogenase/metabolismo
[Mh] Termos MeSH secundário: Sítios de Ligação
Domínio Catalítico
Ligações de Hidrogênio
Modelos Moleculares
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Molybdoferredoxin); 820484N8I3 (Histamine); EC 1.18.6.1 (Nitrogenase)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170519
[Lr] Data última revisão:
170519
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170121
[St] Status:MEDLINE


  10 / 2286 MEDLINE  
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[PMID]:28064366
[Au] Autor:Masukawa H; Sakurai H; Hausinger RP; Inoue K
[Ad] Endereço:The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, 558-8585, Japan. masukawa@ocarina.osaka-cu.ac.jp.
[Ti] Título:Increased heterocyst frequency by patN disruption in Anabaena leads to enhanced photobiological hydrogen production at high light intensity and high cell density.
[So] Source:Appl Microbiol Biotechnol;101(5):2177-2188, 2017 Mar.
[Is] ISSN:1432-0614
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:The effects of increasing the heterocyst-to-vegetative cell ratio on the nitrogenase-based photobiological hydrogen production by the filamentous heterocyst-forming cyanobacterium Anabaena sp. PCC 7120 were studied. Using the uptake hydrogenase-disrupted mutant (ΔHup) as the parent, a deletion-insertion mutant (PN1) was created in patN, known to be involved in heterocyst pattern formation and leading to multiple singular heterocysts (MSH) in Nostoc punctiforme strain ATCC 29133. The PN1 strain showed heterocyst differentiation but failed to grow in medium free of combined-nitrogen; however, a spontaneous mutant (PN22) was obtained on prolonged incubation of PN1 liquid cultures and was able to grow robustly on N . The disruption of patN was confirmed in both PN1 and PN22 by PCR and whole genome resequencing. Under combined-nitrogen limitation, the percentage of heterocysts to total cells in the PN22 filaments was 13-15 and 16-18% under air and 1% CO -enriched air, respectively, in contrast to the parent ΔHup which formed 6.5-11 and 9.7-13% heterocysts in these conditions. The PN22 strain exhibited a MSH phenotype, normal diazotrophic growth, and higher H productivity at high cell concentrations, and was less susceptible to photoinhibition by strong light than the parent ΔHup strain, resulting in greater light energy utilization efficiency in H production on a per unit area basis under high light conditions. The increase in MSH frequency shown here appears to be a viable strategy for enhancing H productivity by outdoor cultures of cyanobacteria in high-light environments.
[Mh] Termos MeSH primário: Anabaena/genética
Anabaena/metabolismo
Hidrogênio/metabolismo
Fotobiorreatores/microbiologia
[Mh] Termos MeSH secundário: Acetileno/metabolismo
Proteínas de Bactérias/genética
Regulação Bacteriana da Expressão Gênica
Fixação de Nitrogênio/genética
Fixação de Nitrogênio/fisiologia
Nitrogenase/metabolismo
Nostoc/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 7YNJ3PO35Z (Hydrogen); EC 1.18.6.1 (Nitrogenase); OC7TV75O83 (Acetylene)
[Em] Mês de entrada:1702
[Cu] Atualização por classe:170227
[Lr] Data última revisão:
170227
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170109
[St] Status:MEDLINE
[do] DOI:10.1007/s00253-016-8078-3



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