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  1 / 28 MEDLINE  
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[PMID]:28057796
[Au] Autor:Sekine K; Moriyama T; Kim J; Hase T; Sato N
[Ad] Endereço:Komaba Organization for Educational Excellence, College of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan.
[Ti] Título:Characterization of two ferredoxin-dependent sulfite reductases having different substrate specificity in the red alga Cyanidioschyzon merolae.
[So] Source:J Biochem;162(1):37-43, 2017 Jul 01.
[Is] ISSN:1756-2651
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Assimilatory sulfite reductase (SiR) and nitrite reductase (NiR), which are important determinants in biomass productivity, are homologous enzymes that catalyze the reduction of sulfite to sulfide and nitrite to ammonium, respectively. They have a siroheme and a [4Fe-4S] cluster as prosthetic groups in common. The red alga Cyanidioschyzon merolae encodes two SiR-like enzymes, CmSiRA and CmSiRB, which are likely products of recent gene duplication, but no homologues of NiR. The growth in a medium containing nitrate, however, must be supported by a nitrite reducing activity. CmSiRB was not detected in the ammonium medium, but, in the nitrate medium, it was present at a level 1/6 of that of constitutively expressed CmSiRA. Kinetic analysis of the two enzymes showed that CmSiRA has high kcat values with both sulfite and nitrite, but CmSiRB has virtually only the activity of nitrite reduction, although the Km value against nitrite was fairly high in both enzymes. The six amino acid residues that are specific to CmSiRB among various SiR-like enzymes in the active site were mutagenized to mimic partially CmSiRA. Among them, the mutation S217C in CmSiRB partially recovered sulfite reduction activity, suggesting that this residue is a major determinant of substrate specificity.
[Mh] Termos MeSH primário: Rodófitas/enzimologia
Sulfito Redutase (Ferredoxina)/metabolismo
Sulfitos/metabolismo
[Mh] Termos MeSH secundário: Especificidade por Substrato
Sulfito Redutase (Ferredoxina)/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Sulfites); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin))
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171013
[Lr] Data última revisão:
171013
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170107
[St] Status:MEDLINE
[do] DOI:10.1093/jb/mvw103


  2 / 28 MEDLINE  
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[PMID]:27551107
[Au] Autor:Kim JY; Kinoshita M; Kume S; Gt H; Sugiki T; Ladbury JE; Kojima C; Ikegami T; Kurisu G; Goto Y; Hase T; Lee YH
[Ad] Endereço:Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
[Ti] Título:Non-covalent forces tune the electron transfer complex between ferredoxin and sulfite reductase to optimize enzymatic activity.
[So] Source:Biochem J;473(21):3837-3854, 2016 Nov 01.
[Is] ISSN:1470-8728
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Although electrostatic interactions between negatively charged ferredoxin (Fd) and positively charged sulfite reductase (SiR) have been predominantly highlighted to characterize complex formation, the detailed nature of intermolecular forces remains to be fully elucidated. We investigated interprotein forces for the formation of an electron transfer complex between Fd and SiR and their relationship to SiR activity using various approaches over NaCl concentrations between 0 and 400 mM. Fd-dependent SiR activity assays revealed a bell-shaped activity curve with a maximum ∼40-70 mM NaCl and a reverse bell-shaped dependence of interprotein affinity. Meanwhile, intrinsic SiR activity, as measured in a methyl viologen-dependent assay, exhibited saturation above 100 mM NaCl. Thus, two assays suggested that interprotein interaction is crucial in controlling Fd-dependent SiR activity. Calorimetric analyses showed the monotonic decrease in interprotein affinity on increasing NaCl concentrations, distinguished from a reverse bell-shaped interprotein affinity observed from Fd-dependent SiR activity assay. Furthermore, Fd:SiR complex formation and interprotein affinity were thermodynamically adjusted by both enthalpy and entropy through electrostatic and non-electrostatic interactions. A residue-based NMR investigation on the addition of SiR to N-labeled Fd at the various NaCl concentrations also demonstrated that a combination of electrostatic and non-electrostatic forces stabilized the complex with similar interfaces and modulated the binding affinity and mode. Our findings elucidate that non-electrostatic forces are also essential for the formation and modulation of the Fd:SiR complex. We suggest that a complex configuration optimized for maximum enzymatic activity near physiological salt conditions is achieved by structural rearrangement through controlled non-covalent interprotein interactions.
[Mh] Termos MeSH primário: Ferredoxinas/metabolismo
Sulfito Redutase (Ferredoxina)/metabolismo
[Mh] Termos MeSH secundário: Calorimetria
Dicroísmo Circular
Transporte de Elétrons/efeitos dos fármacos
Espectroscopia de Ressonância Magnética
Oxirredução/efeitos dos fármacos
Cloreto de Sódio/farmacologia
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Ferredoxins); 451W47IQ8X (Sodium Chloride); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin))
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170612
[Lr] Data última revisão:
170612
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160824
[St] Status:MEDLINE


  3 / 28 MEDLINE  
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[PMID]:27182957
[Au] Autor:Fisher B; Yarmolinsky D; Abdel-Ghany S; Pilon M; Pilon-Smits EA; Sagi M; Van Hoewyk D
[Ad] Endereço:Coastal Carolina University, Biology Department, Conway, SC, 29526, USA. Electronic address: bjfisher@g.coastal.edu.
[Ti] Título:Superoxide generated from the glutathione-mediated reduction of selenite damages the iron-sulfur cluster of chloroplastic ferredoxin.
[So] Source:Plant Physiol Biochem;106:228-35, 2016 Sep.
[Is] ISSN:1873-2690
[Cp] País de publicação:France
[La] Idioma:eng
[Ab] Resumo:Selenium assimilation in plants is facilitated by several enzymes that participate in the transport and assimilation of sulfate. Manipulation of genes that function in sulfur metabolism dramatically affects selenium toxicity and accumulation. However, it has been proposed that selenite is not reduced by sulfite reductase. Instead, selenite can be non-enzymatically reduced by glutathione, generating selenodiglutathione and superoxide. The damaging effects of superoxide on iron-sulfur clusters in cytosolic and mitochondrial proteins are well known. However, it is unknown if superoxide damages chloroplastic iron-sulfur proteins. The goals of this study were twofold: to determine whether decreased activity of sulfite reductase impacts selenium tolerance in Arabidopsis, and to determine if superoxide generated from the glutathione-mediated reduction of selenite damages the iron-sulfur cluster of ferredoxin. Our data demonstrate that knockdown of sulfite reductase in Arabidopsis does not affect selenite tolerance or selenium accumulation. Additionally, we provide in vitro evidence that the non-enzymatic reduction of selenite damages the iron-sulfur cluster of ferredoxin, a plastidial protein that is an essential component of the photosynthetic light reactions. Damage to ferredoxin's iron-sulfur cluster was associated with formation of apo-ferredoxin and impaired activity. We conclude that if superoxide damages iron-sulfur clusters of ferredoxin in planta, then it might contribute to photosynthetic impairment often associated with abiotic stress, including toxic levels of selenium.
[Mh] Termos MeSH primário: Arabidopsis/metabolismo
Cloroplastos/metabolismo
Ferredoxinas/metabolismo
Glutationa/metabolismo
Proteínas com Ferro-Enxofre/metabolismo
Ácido Selenioso/toxicidade
Superóxidos/metabolismo
[Mh] Termos MeSH secundário: Arabidopsis/efeitos dos fármacos
Cloroplastos/efeitos dos fármacos
Citocromos c/metabolismo
Eletroforese em Gel de Poliacrilamida
Ferredoxina-NADP Redutase/metabolismo
Técnicas de Silenciamento de Genes
NADP/metabolismo
Análise Espectral
Sulfito Redutase (Ferredoxina)
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Ferredoxins); 0 (Iron-Sulfur Proteins); 11062-77-4 (Superoxides); 53-59-8 (NADP); 9007-43-6 (Cytochromes c); EC 1.18.1.2 (Ferredoxin-NADP Reductase); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin)); F6A27P4Q4R (Selenious Acid); GAN16C9B8O (Glutathione)
[Em] Mês de entrada:1703
[Cu] Atualização por classe:170327
[Lr] Data última revisão:
170327
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160517
[St] Status:MEDLINE


  4 / 28 MEDLINE  
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[PMID]:26920048
[Au] Autor:Kim JY; Nakayama M; Toyota H; Kurisu G; Hase T
[Ad] Endereço:Division of Protein Chemistry and.
[Ti] Título:Structural and mutational studies of an electron transfer complex of maize sulfite reductase and ferredoxin.
[So] Source:J Biochem;160(2):101-9, 2016 Aug.
[Is] ISSN:1756-2651
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The structure of the complex of maize sulfite reductase (SiR) and ferredoxin (Fd) has been determined by X-ray crystallography. Co-crystals of the two proteins prepared under different conditions were subjected to the diffraction analysis and three possible structures of the complex were solved. Although topological relationship of SiR and Fd varied in each of the structures, two characteristics common to all structures were found in the pattern of protein-protein interactions and positional arrangements of redox centres; (i) a few negative residues of Fd contact with a narrow area of SiR with positive electrostatic surface potential and (ii) [2Fe-2S] cluster of Fd and [4Fe-4S] cluster of SiR are in a close proximity with the shortest distance around 12 Å. Mutational analysis of a total of seven basic residues of SiR distributed widely at the interface of the complex showed their importance for supporting an efficient Fd-dependent activity and a strong physical binding to Fd. These combined results suggest that the productive electron transfer complex of SiR and Fd could be formed through multiple processes of the electrostatic intermolecular interaction and this implication is discussed in terms of the multi-functionality of Fd in various redox metabolisms.
[Mh] Termos MeSH primário: Mutação de Sentido Incorreto
Proteínas de Plantas/química
Sulfito Redutase (Ferredoxina)/química
Zea mays/enzimologia
[Mh] Termos MeSH secundário: Substituição de Aminoácidos
Proteínas de Plantas/genética
Domínios Proteicos
Sulfito Redutase (Ferredoxina)/genética
Zea mays/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Plant Proteins); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin))
[Em] Mês de entrada:1701
[Cu] Atualização por classe:170130
[Lr] Data última revisão:
170130
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160228
[St] Status:MEDLINE
[do] DOI:10.1093/jb/mvw016


  5 / 28 MEDLINE  
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[PMID]:23197358
[Au] Autor:Zhou Q; Hu M; Zhang W; Jiang L; Perrett S; Zhou J; Wang J
[Ad] Endereço:Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China.
[Ti] Título:Probing the function of the Tyr-Cys cross-link in metalloenzymes by the genetic incorporation of 3-methylthiotyrosine.
[So] Source:Angew Chem Int Ed Engl;52(4):1203-7, 2013 Jan 21.
[Is] ISSN:1521-3773
[Cp] País de publicação:Germany
[La] Idioma:eng
[Mh] Termos MeSH primário: Cisteína/metabolismo
Tirosina/metabolismo
[Mh] Termos MeSH secundário: Animais
Domínio Catalítico
Cisteína/química
Cisteína Dioxigenase/metabolismo
Citocromos a1/química
Citocromos a1/metabolismo
Citocromos c1/química
Citocromos c1/metabolismo
Galactose Oxidase/metabolismo
Mutagênese Sítio-Dirigida
Mioglobina/genética
Mioglobina/metabolismo
Nitrato Redutases/química
Nitrato Redutases/metabolismo
Oxirredução
Sulfito Redutase (Ferredoxina)/metabolismo
Tirosina/análogos & derivados
Baleias
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Myoglobin); 42HK56048U (Tyrosine); 9035-35-2 (Cytochromes a1); 9035-42-1 (Cytochromes c1); EC 1.1.3.9 (Galactose Oxidase); EC 1.13.11.20 (Cysteine Dioxygenase); EC 1.7.- (Nitrate Reductases); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin)); EC 1.9.6.1 (nitrate reductase (cytochrome)); K848JZ4886 (Cysteine)
[Em] Mês de entrada:1306
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:121201
[St] Status:MEDLINE
[do] DOI:10.1002/anie.201207229


  6 / 28 MEDLINE  
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[PMID]:22944351
[Au] Autor:McManus MT; Joshi S; Searle B; Pither-Joyce M; Shaw M; Leung S; Albert N; Shigyo M; Jakse J; Havey MJ; McCallum J
[Ad] Endereço:Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand. M.T.McManus@massey.ac.nz
[Ti] Título:Genotypic variation in sulfur assimilation and metabolism of onion (Allium cepa L.) III. Characterization of sulfite reductase.
[So] Source:Phytochemistry;83:34-42, 2012 Nov.
[Is] ISSN:1873-3700
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Genomic and cDNA sequences corresponding to a ferredoxin-sulfite reductase (SiR) have been cloned from bulb onion (Allium cepa L.) and the expression of the gene and activity of the enzyme characterized with respect to sulfur (S) supply. Cloning, mapping and expression studies revealed that onion has a single functional SiR gene and also expresses an unprocessed pseudogene (φ-SiR). Northern and qPCR analysis revealed differences in expression pattern between the SiR gene and the pseudogene. Western analysis using antibodies raised to a recombinant SiR revealed that the enzyme is present in chloroplasts and phylogenetic analysis has shown that the onion protein groups with lower eudicots. In hydroponically-grown plants, levels of SiR transcripts were significantly higher in the roots of S-sufficient when compared with S-deficient plants of the pungent cultivar 'W202A' but not the less pungent cultivar 'Texas Grano'. In these same treatments, a higher level of enzyme activity was observed in the S-sufficient treatment in leaves of both cultivars before and after bulbing. In a factorial field trial with and without sulfur fertilization, a statistically significant increase in SiR activity was observed in the leaves of the pungent cultivar 'Kojak' in response to added S but not in the less pungent cultivar 'Encore'.
[Mh] Termos MeSH primário: Variação Genética/genética
Genótipo
Cebolas/enzimologia
Cebolas/metabolismo
Sulfito Redutase (Ferredoxina)/genética
Enxofre/metabolismo
[Mh] Termos MeSH secundário: Clonagem Molecular
Ativação Enzimática
Regulação Enzimológica da Expressão Gênica
Regulação da Expressão Gênica de Plantas/genética
Reação em Cadeia da Polimerase Via Transcriptase Reversa
Sulfito Redutase (Ferredoxina)/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
70FD1KFU70 (Sulfur); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin))
[Em] Mês de entrada:1308
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:120905
[St] Status:MEDLINE


  7 / 28 MEDLINE  
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[PMID]:22607201
[Au] Autor:Nakatani T; Ohtsu I; Nonaka G; Wiriyathanawudhiwong N; Morigasaki S; Takagi H
[Ad] Endereço:Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
[Ti] Título:Enhancement of thioredoxin/glutaredoxin-mediated L-cysteine synthesis from S-sulfocysteine increases L-cysteine production in Escherichia coli.
[So] Source:Microb Cell Fact;11:62, 2012 May 18.
[Is] ISSN:1475-2859
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Escherichia coli has two L-cysteine biosynthetic pathways; one is synthesized from O-acetyl L-serine (OAS) and sulfate by L-cysteine synthase (CysK), and another is produced via S-sulfocysteine (SSC) from OAS and thiosulfate by SSC synthase (CysM). SSC is converted into L-cysteine and sulfite by an uncharacterized reaction. As thioredoxins (Trx1 and Trx2) and glutaredoxins (Grx1, Grx2, Grx3, Grx4, and NrdH) are known as reductases of peptidyl disulfides, overexpression of such reductases might be a good way for improving L-cysteine production to accelerate the reduction of SSC in E. coli. RESULTS: Because the redox enzymes can reduce the disulfide that forms on proteins, we first tested whether these enzymes catalyze the reduction of SSC to L-cysteine. All His-tagged recombinant enzymes, except for Grx4, efficiently convert SSC into L-cysteine in vitro. Overexpression of Grx1 and NrdH enhanced a 15-40% increase in the E. coliL-cysteine production. On the other hand, disruption of the cysM gene cancelled the effect caused by the overexpression of Grx1 and NrdH, suggesting that its improvement was due to the efficient reduction of SSC under the fermentative conditions. Moreover, L-cysteine production in knockout mutants of the sulfite reductase genes (ΔcysI and ΔcysJ) and the L-cysteine synthase gene (ΔcysK) each decreased to about 50% of that in the wild-type strain. Interestingly, there was no significant difference in L-cysteine production between wild-type strain and gene deletion mutant of the upstream pathway of sulfite (ΔcysC or ΔcysH). These results indicate that sulfite generated from the SSC reduction is available as the sulfur source to produce additional L-cysteine molecule. It was finally found that in the E. coliL-cysteine producer that co-overexpress glutaredoxin (NrdH), sulfite reductase (CysI), and L-cysteine synthase (CysK), there was the highest amount of L-cysteine produced per cell. CONCLUSIONS: In this work, we showed that Grx1 and NrdH reduce SSC to L-cysteine, and the generated sulfite is then utilized as the sulfur source to produce additional L-cysteine molecule through the sulfate pathway in E. coli. We also found that co-overexpression of NrdH, CysI, and CysK increases L-cysteine production. Our results propose that the enhancement of thioredoxin/glutaredoxin-mediated L-cysteine synthesis from SSC is a novel method for improvement of L-cysteine production.
[Mh] Termos MeSH primário: Cisteína/análogos & derivados
Cisteína/biossíntese
Escherichia coli/metabolismo
Glutarredoxinas/metabolismo
Tiorredoxinas/metabolismo
[Mh] Termos MeSH secundário: Cisteína/metabolismo
Cisteína Sintase/genética
Cisteína Sintase/metabolismo
Escherichia coli/genética
Glutarredoxinas/genética
Oxirredução
Proteínas Recombinantes/biossíntese
Proteínas Recombinantes/genética
Sulfito Redutase (Ferredoxina)/genética
Sulfito Redutase (Ferredoxina)/metabolismo
Tiorredoxinas/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Glutaredoxins); 0 (Recombinant Proteins); 52500-60-4 (Thioredoxins); 885F2S42LL (S-sulphocysteine); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin)); EC 2.5.1.47 (Cysteine Synthase); K848JZ4886 (Cysteine)
[Em] Mês de entrada:1304
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:120522
[St] Status:MEDLINE
[do] DOI:10.1186/1475-2859-11-62


  8 / 28 MEDLINE  
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[PMID]:21945528
[Au] Autor:Ewen KM; Hannemann F; Iametti S; Morleo A; Bernhardt R
[Ad] Endereço:Department of Biochemistry, Saarland University, D-66041 Saarbrücken, Germany.
[Ti] Título:Functional characterization of Fdx1: evidence for an evolutionary relationship between P450-type and ISC-type ferredoxins.
[So] Source:J Mol Biol;413(5):940-51, 2011 Nov 11.
[Is] ISSN:1089-8638
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Ferredoxins are ubiquitous proteins with electron transfer activity involved in a variety of biological processes. In this work, we investigated the characteristics and function of Fdx1 from Sorangium cellulosum So ce56 by using a combination of bioinformatics and of biochemical/biophysical approaches. We were able to experimentally confirm a role of Fdx1 in the iron-sulfur cluster biosynthesis by in vitro reduction studies with cluster-loaded So ce56 IscU and by transfer studies of the cluster from the latter protein to apo-aconitase A. Moreover, we found that Fdx1 can replace mammalian adrenodoxin in supporting the activity of bovine CYP11A1. This makes S. cellulosum Fdx1 the first prokaryotic ferredoxin reported to functionally interact with this mammalian enzyme. Although the interaction with CYP11A1 is non-physiological, this is-to the best of our knowledge-the first study to experimentally prove the activity of a postulated ISC-type ferredoxin in both the ISC assembly and a cytochrome P450 system. This proves that a single ferredoxin can be structurally able to provide electrons to both cytochromes P450 and IscU and thus support different biochemical processes. Combining this finding with phylogenetic and evolutionary trace analyses led us to propose the evolution of eukaryotic mitochondrial P450-type ferredoxins and ISC-type ferredoxins from a common prokaryotic ISC-type ancestor.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Proteínas de Bactérias/metabolismo
Enzima de Clivagem da Cadeia Lateral do Colesterol/química
Evolução Molecular
Ferredoxinas/química
Ferredoxinas/metabolismo
Proteínas com Ferro-Enxofre/química
Mitocôndrias/enzimologia
[Mh] Termos MeSH secundário: Aconitato Hidratase/metabolismo
Sequência de Aminoácidos
Animais
Proteínas de Bactérias/isolamento & purificação
Bovinos
Enzima de Clivagem da Cadeia Lateral do Colesterol/metabolismo
Dicroísmo Circular
Clonagem Molecular
Biologia Computacional
Ferredoxinas/isolamento & purificação
Ferro/análise
Proteínas com Ferro-Enxofre/metabolismo
Dados de Sequência Molecular
Myxococcales/genética
Myxococcales/metabolismo
NADP
Oxirredução
Filogenia
Homologia de Sequência de Aminoácidos
Sulfito Redutase (Ferredoxina)/metabolismo
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Ferredoxins); 0 (Iron-Sulfur Proteins); 53-59-8 (NADP); E1UOL152H7 (Iron); EC 1.14.15.6 (Cholesterol Side-Chain Cleavage Enzyme); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin)); EC 4.2.1.3 (Aconitate Hydratase)
[Em] Mês de entrada:1201
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:110928
[St] Status:MEDLINE
[do] DOI:10.1016/j.jmb.2011.09.010


  9 / 28 MEDLINE  
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[PMID]:19622064
[Au] Autor:Sekine K; Sakakibara Y; Hase T; Sato N
[Ad] Endereço:Center for Structuring Life Sciences, University of Tokyo, Meguro-ku, Japan.
[Ti] Título:A novel variant of ferredoxin-dependent sulfite reductase having preferred substrate specificity for nitrite in the unicellular red alga Cyanidioschyzon merolae.
[So] Source:Biochem J;423(1):91-8, 2009 Sep 14.
[Is] ISSN:1470-8728
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Plant NiR (nitrite reductase) and SiR (sulfite reductase) have common structural and functional features. Both enzymes are generally distinguished in terms of substrate specificity for nitrite and sulfite. The genome of Cyanidioschyzon merolae, a unicellular red alga living in acidic hot springs, encodes two SiR homologues, namely CmSiRA and CmSiRB (C. merolae sulfite reductases A and B), but no NiR homologue. The fact that most known SiRs have a low nitrite-reducing activity and that the CmSiRB gene is mapped between the genes for nitrate transporter and nitrate reductase implies that CmSiRB could have a potential to function as a nitrite-reducing enzyme. To verify this hypothesis, we produced a recombinant form of CmSiRB and characterized its enzymatic properties. The enzyme was found to have a significant nitrite-reducing activity, whereas its sulfite-reducing activity was extremely low. As the affinity of CmSiRB for sulfite was higher by 25-fold than that for nitrite, nitrite reduction by CmSiRB was competitively inhibited by sulfite. These results demonstrate that CmSiRB is a unique SiR having a decreased sulfite-reducing activity and an enhanced nitrite-reducing activity. The cellular level of CmSiRB was significantly increased when C. merolae was grown in a nitrate medium. The nitrate-grown C. merolae cells showed a high nitrite uptake from the growth medium, and this consumption was inhibited by sulfite. These combined results indicate that CmSiRB has a significant nitrite-reducing activity and plays a physiological role in nitrate assimilation.
[Mh] Termos MeSH primário: Nitritos/metabolismo
Rodófitas/enzimologia
Sulfito Redutase (Ferredoxina)/metabolismo
[Mh] Termos MeSH secundário: Células Cultivadas
Clonagem Molecular
Isoenzimas/genética
Isoenzimas/metabolismo
Isoenzimas/fisiologia
Cinética
NADP/metabolismo
NADP/farmacocinética
Oxirredução
Filogenia
Rodófitas/genética
Rodófitas/metabolismo
Especificidade por Substrato
Sulfito Redutase (Ferredoxina)/genética
Sulfito Redutase (Ferredoxina)/fisiologia
Sulfitos/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Isoenzymes); 0 (Nitrites); 0 (Sulfites); 53-59-8 (NADP); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin))
[Em] Mês de entrada:0910
[Cu] Atualização por classe:101118
[Lr] Data última revisão:
101118
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:090723
[St] Status:MEDLINE
[do] DOI:10.1042/BJ20090581


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[PMID]:18162174
[Au] Autor:Lee SY; Song JY; Kwon ES; Roe JH
[Ad] Endereço:Laboratory of Molecular Microbiology, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Kwanak-gu, Seoul 151-742, Republic of Korea.
[Ti] Título:Gpx1 is a stationary phase-specific thioredoxin peroxidase in fission yeast.
[So] Source:Biochem Biophys Res Commun;367(1):67-71, 2008 Feb 29.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The genome sequence of Schizosaccharomyces pombe reveals only one gene for a putative glutathione peroxidase (gpx1(+)). The Gpx1 protein has a peroxidase activity but preferred thioredoxin to glutathione as an electron donor when examined in vitro and in vivo, and therefore is a thioredoxin peroxidase. Besides H(2)O(2), it can reduce alkyl and phospholipid hydroperoxides. Expression of the gpx1 gene was elevated at the stationary phase, and we found that it supported long-term survival of S. pombe. The mutant also exhibited some defect in the activity of aconitase, an oxidation-labile Fe-S enzyme in mitochondria. Activity of sulfite reductase, a labile Fe-S enzyme in the cytosol, was also dramatically lowered in the mutant in the stationary phase. The Gpx1 protein, without any obvious targeting sequence, was localized in mitochondria as well as in the cytosol. Therefore, Gpx1 must serve to ensure optimal mitochondrial function and cytosolic environment, especially in the stationary phase.
[Mh] Termos MeSH primário: Glutationa Peroxidase/metabolismo
Peroxirredoxinas/metabolismo
Schizosaccharomyces/enzimologia
[Mh] Termos MeSH secundário: Aconitato Hidratase/metabolismo
Sequência de Bases
Citosol/enzimologia
Eletroforese em Gel de Poliacrilamida
Regulação Fúngica da Expressão Gênica/genética
Regulação Fúngica da Expressão Gênica/fisiologia
Glutationa/metabolismo
Glutationa Peroxidase/genética
Mitocôndrias/enzimologia
Mitocôndrias/genética
Mutação
Estresse Oxidativo/genética
Estresse Oxidativo/fisiologia
Schizosaccharomyces/genética
Sulfito Redutase (Ferredoxina)/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
EC 1.11.1.- (glutathione peroxidase GPX1); EC 1.11.1.15 (Peroxiredoxins); EC 1.11.1.9 (Glutathione Peroxidase); EC 1.8.7.1 (Sulfite Reductase (Ferredoxin)); EC 4.2.1.3 (Aconitate Hydratase); GAN16C9B8O (Glutathione)
[Em] Mês de entrada:0803
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:071229
[St] Status:MEDLINE



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