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  1 / 17786 MEDLINE  
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[PMID]:28463568
[Au] Autor:Salinas G; Gao W; Wang Y; Bonilla M; Yu L; Novikov A; Virginio VG; Ferreira HB; Vieites M; Gladyshev VN; Gambino D; Dai S
[Ad] Endereço:1 Worm Biology Lab, Institut Pasteur de Montevideo , Montevideo, Uruguay .
[Ti] Título:The Enzymatic and Structural Basis for Inhibition of Echinococcus granulosus Thioredoxin Glutathione Reductase by Gold(I).
[So] Source:Antioxid Redox Signal;27(18):1491-1504, 2017 Dec 20.
[Is] ISSN:1557-7716
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:AIMS: New drugs are needed to treat flatworm infections that cause severe human diseases such as schistosomiasis. The unique flatworm enzyme thioredoxin glutathione reductase (TGR), structurally different from the human enzyme, is a key drug target. Structural studies of the flatworm Echinococcus granulosus TGR, free and complexed with Au -MPO, a novel gold inhibitor, together with inhibition assays were performed. RESULTS: Au -MPO is a potent TGR inhibitor that achieves 75% inhibition at a 1:1 TGR:Au ratio and efficiently kills E. granulosus in vitro. The structures revealed salient insights: (i) unique monomer-monomer interactions, (ii) distinct binding sites for thioredoxin and the glutaredoxin (Grx) domain, (iii) a single glutathione disulfide reduction site in the Grx domain, (iv) rotation of the Grx domain toward the Sec-containing redox active site, and (v) a single gold atom bound to Cys and Cys in the Au -TGR complex. Structural modeling suggests that these residues are involved in the stabilization of the Sec-containing C-terminus. Consistently, Cys→Ser mutations in these residues decreased TGR activities. Mass spectroscopy confirmed these cysteines are the primary binding site. INNOVATION: The identification of a primary site for gold binding and the structural model provide a basis for gold compound optimization through scaffold adjustments. CONCLUSIONS: The structural study revealed that TGR functions are achieved not only through a mobile Sec-containing redox center but also by rotation of the Grx domain and distinct binding sites for Grx domain and thioredoxin. The conserved Cys and Cys residues targeted by gold assist catalysis through stabilization of the Sec-containing redox center. Antioxid. Redox Signal. 27, 1491-1504.
[Mh] Termos MeSH primário: Echinococcus granulosus/enzimologia
Complexos Multienzimáticos/química
Complexos Multienzimáticos/metabolismo
NADH NADPH Oxirredutases/química
NADH NADPH Oxirredutases/metabolismo
Compostos Organoáuricos/farmacologia
[Mh] Termos MeSH secundário: Animais
Sítios de Ligação/efeitos dos fármacos
Cisteína/metabolismo
Echinococcus granulosus/química
Echinococcus granulosus/genética
Inibidores Enzimáticos/química
Inibidores Enzimáticos/farmacocinética
Glutarredoxinas/metabolismo
Proteínas de Helminto/química
Proteínas de Helminto/genética
Proteínas de Helminto/metabolismo
Modelos Moleculares
Complexos Multienzimáticos/genética
Mutação
NADH NADPH Oxirredutases/genética
Compostos Organoáuricos/química
Ligação Proteica
Conformação Proteica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Enzyme Inhibitors); 0 (Glutaredoxins); 0 (Helminth Proteins); 0 (Multienzyme Complexes); 0 (Organogold Compounds); EC 1.6.- (NADH, NADPH Oxidoreductases); EC 1.6.4.- (thioredoxin glutathione reductase); K848JZ4886 (Cysteine)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE
[do] DOI:10.1089/ars.2016.6816


  2 / 17786 MEDLINE  
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[PMID]:29311576
[Au] Autor:Razew M; Warkocki Z; Taube M; Kolondra A; Czarnocki-Cieciura M; Nowak E; Labedzka-Dmoch K; Kawinska A; Piatkowski J; Golik P; Kozak M; Dziembowski A; Nowotny M
[Ad] Endereço:Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Trojdena 4, 02-109, Warsaw, Poland.
[Ti] Título:Structural analysis of mtEXO mitochondrial RNA degradosome reveals tight coupling of nuclease and helicase components.
[So] Source:Nat Commun;9(1):97, 2018 01 08.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Nuclease and helicase activities play pivotal roles in various aspects of RNA processing and degradation. These two activities are often present in multi-subunit complexes from nucleic acid metabolism. In the mitochondrial exoribonuclease complex (mtEXO) both enzymatic activities are tightly coupled making it an excellent minimal system to study helicase-exoribonuclease coordination. mtEXO is composed of Dss1 3'-to-5' exoribonuclease and Suv3 helicase. It is the master regulator of mitochondrial gene expression in yeast. Here, we present the structure of mtEXO and a description of its mechanism of action. The crystal structure of Dss1 reveals domains that are responsible for interactions with Suv3. Importantly, these interactions are compatible with the conformational changes of Suv3 domains during the helicase cycle. We demonstrate that mtEXO is an intimate complex which forms an RNA-binding channel spanning its entire structure, with Suv3 helicase feeding the 3' end of the RNA toward the active site of Dss1.
[Mh] Termos MeSH primário: Endorribonucleases/metabolismo
Exorribonucleases/metabolismo
Proteínas Mitocondriais/metabolismo
Complexos Multienzimáticos/metabolismo
Polirribonucleotídeo Nucleotidiltransferase/metabolismo
RNA Helicases/metabolismo
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Sequência de Bases
Candida glabrata/enzimologia
Candida glabrata/genética
Candida glabrata/metabolismo
Cristalografia por Raios X
RNA Helicases DEAD-box/química
RNA Helicases DEAD-box/genética
RNA Helicases DEAD-box/metabolismo
Endorribonucleases/química
Endorribonucleases/genética
Exorribonucleases/química
Exorribonucleases/genética
Proteínas Mitocondriais/química
Proteínas Mitocondriais/genética
Complexos Multienzimáticos/química
Complexos Multienzimáticos/genética
Conformação de Ácido Nucleico
Polirribonucleotídeo Nucleotidiltransferase/química
Polirribonucleotídeo Nucleotidiltransferase/genética
Ligação Proteica
Conformação Proteica
RNA/química
RNA/genética
RNA/metabolismo
RNA Helicases/química
RNA Helicases/genética
Saccharomyces cerevisiae/enzimologia
Saccharomyces cerevisiae/genética
Saccharomyces cerevisiae/metabolismo
Proteínas de Saccharomyces cerevisiae/química
Proteínas de Saccharomyces cerevisiae/genética
Proteínas de Saccharomyces cerevisiae/metabolismo
Homologia de Sequência de Aminoácidos
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Mitochondrial Proteins); 0 (Multienzyme Complexes); 0 (RNA, mitochondrial); 0 (Saccharomyces cerevisiae Proteins); 0 (degradosome); 63231-63-0 (RNA); EC 2.7.7.8 (Polyribonucleotide Nucleotidyltransferase); EC 3.1.- (Endoribonucleases); EC 3.1.- (Exoribonucleases); EC 3.1.13.1 (DSS1 protein, S cerevisiae); EC 3.6.1.- (SUV3 protein, S cerevisiae); EC 3.6.4.13 (DEAD-box RNA Helicases); EC 3.6.4.13 (RNA Helicases)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180305
[Lr] Data última revisão:
180305
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180110
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-02570-5


  3 / 17786 MEDLINE  
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[PMID]:29242153
[Au] Autor:Raj R; Mitra S; Gopal B
[Ad] Endereço:Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
[Ti] Título:Characterization of Staphylococcus epidermidis Polynucleotide phosphorylase and its interactions with ribonucleases RNase J1 and RNase J2.
[So] Source:Biochem Biophys Res Commun;495(2):2078-2084, 2018 01 08.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Polynucleotide phosphorylase catalyzes both 3'-5' exoribonuclease and polyadenylation reactions. The crystal structure of Staphylococcus epidermidis PNPase revealed a bound phosphate in the PH2 domain of each protomer coordinated by three adjacent serine residues. Mutational analysis suggests that phosphate coordination by these serine residues is essential to maintain the catalytic center in an active conformation. We note that PNPase forms a complex with RNase J1 and RNase J2 without substantially altering either exo-ribonuclease or polyadenylation activity of this enzyme. This decoupling of catalytic activity from protein-protein interactions suggests that association of these endo- or exo-ribonucleases with PNPase could be more relevant for cellular localization or concerted targeting of structured RNA for recycling.
[Mh] Termos MeSH primário: Simulação de Acoplamento Molecular
Nucleotidiltransferases/química
Nucleotidiltransferases/ultraestrutura
Ribonucleases/química
Ribonucleases/ultraestrutura
Staphylococcus epidermidis/enzimologia
[Mh] Termos MeSH secundário: Sítios de Ligação
Ativação Enzimática
Estabilidade Enzimática
Modelos Químicos
Complexos Multienzimáticos
Ligação Proteica
Conformação Proteica
Relação Estrutura-Atividade
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Multienzyme Complexes); EC 2.7.7.- (Nucleotidyltransferases); EC 2.7.7.- (polynucleotide pyrophosphorylase); EC 3.1.- (Ribonucleases)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180214
[Lr] Data última revisão:
180214
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171216
[St] Status:MEDLINE


  4 / 17786 MEDLINE  
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[PMID]:29321177
[Au] Autor:Wang W; Daley JM; Kwon Y; Krasner DS; Sung P
[Ad] Endereço:Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
[Ti] Título:Plasticity of the Mre11-Rad50-Xrs2-Sae2 nuclease ensemble in the processing of DNA-bound obstacles.
[So] Source:Genes Dev;31(23-24):2331-2336, 2017 12 01.
[Is] ISSN:1549-5477
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The budding yeast Mre11-Rad50-Xrs2 (MRX) complex and Sae2 function together in DNA end resection during homologous recombination. Here we show that the Ku complex shields DNA ends from exonucleolytic digestion but facilitates endonucleolytic scission by MRX with a dependence on ATP and Sae2. The incision site is enlarged into a DNA gap via the exonuclease activity of MRX, which is stimulated by Sae2 without ATP being present. RPA renders a partially resected or palindromic DNA structure susceptible to MRX-Sae2, and internal protein blocks also trigger DNA cleavage. We present models for how MRX-Sae2 creates entry sites for the long-range resection machinery.
[Mh] Termos MeSH primário: Reparo do DNA por Junção de Extremidades
Reparo do DNA/fisiologia
Endonucleases/metabolismo
Exonucleases/metabolismo
Complexos Multienzimáticos/metabolismo
Proteínas de Saccharomyces cerevisiae/metabolismo
Saccharomyces cerevisiae/fisiologia
[Mh] Termos MeSH secundário: Clivagem do DNA
Proteínas de Ligação a DNA/metabolismo
Endodesoxirribonucleases/metabolismo
Ativação Enzimática/genética
Exodesoxirribonucleases/metabolismo
Complexos Multiproteicos/metabolismo
Saccharomyces cerevisiae/enzimologia
Saccharomyces cerevisiae/genética
Proteínas de Saccharomyces cerevisiae/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (DNA-Binding Proteins); 0 (Multienzyme Complexes); 0 (Multiprotein Complexes); 0 (RAD50 protein, S cerevisiae); 0 (SAE2 protein, S cerevisiae); 0 (Saccharomyces cerevisiae Proteins); 0 (XRS2 protein, S cerevisiae); 0 (high affinity DNA-binding factor, S cerevisiae); EC 3.1.- (Endodeoxyribonucleases); EC 3.1.- (Endonucleases); EC 3.1.- (Exodeoxyribonucleases); EC 3.1.- (Exonucleases); EC 3.1.- (MRE11 protein, S cerevisiae); EC 3.1.11.1 (exodeoxyribonuclease I)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180208
[Lr] Data última revisão:
180208
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180112
[St] Status:MEDLINE
[do] DOI:10.1101/gad.307900.117


  5 / 17786 MEDLINE  
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[PMID]:28463479
[Au] Autor:Hong CY; Ryu SH; Jeong H; Lee SS; Kim M; Choi IG
[Ad] Endereço:Division of Wood Chemistry & Microbiology, Department of Forest Products, National Institute of Forest Science , Seoul, Republic of Korea.
[Ti] Título:Phanerochaete chrysosporium Multienzyme Catabolic System for in Vivo Modification of Synthetic Lignin to Succinic Acid.
[So] Source:ACS Chem Biol;12(7):1749-1759, 2017 Jul 21.
[Is] ISSN:1554-8937
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Whole cells of the basidiomycete fungus Phanerochaete chrysosporium (ATCC 20696) were applied to induce the biomodification of lignin in an in vivo system. Our results indicated that P. chrysosporium has a catabolic system that induces characteristic biomodifications of synthetic lignin through a series of redox reactions, leading not only to the degradation of lignin but also to its polymerization. The reducing agents ascorbic acid and α-tocopherol were used to stabilize the free radicals generated from the ligninolytic process. The application of P. chrysosporium in combination with reducing agents produced aromatic compounds and succinic acid as well as degraded lignin polymers. P. chrysosporium selectively catalyzed the conversion of lignin to succinic acid, which has an economic value. A transcriptomic analysis of P. chrysosporium suggested that the bond cleavage of synthetic lignin was caused by numerous enzymes, including extracellular enzymes such as lignin peroxidase and manganese peroxidase, and that the aromatic compounds released were metabolized in both the short-cut and classical tricarboxylic acid cycles of P. chrysosporium. In conclusion, P. chrysosporium is suitable as a biocatalyst for lignin degradation to produce a value-added product.
[Mh] Termos MeSH primário: Lignina/metabolismo
Complexos Multienzimáticos/química
Phanerochaete/enzimologia
Ácido Succínico/síntese química
[Mh] Termos MeSH secundário: Ácido Ascórbico/química
Radicais Livres
Lignina/química
Peso Molecular
Nitrobenzenos/química
Oxirredução
Phanerochaete/metabolismo
Ácido Succínico/química
Ácido Succínico/metabolismo
Tocoferóis/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Free Radicals); 0 (Multienzyme Complexes); 0 (Nitrobenzenes); 9005-53-2 (Lignin); AB6MNQ6J6L (Succinic Acid); E57JCN6SSY (nitrobenzene); PQ6CK8PD0R (Ascorbic Acid); R0ZB2556P8 (Tocopherols)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180207
[Lr] Data última revisão:
180207
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE
[do] DOI:10.1021/acschembio.7b00046


  6 / 17786 MEDLINE  
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[PMID]:28247940
[Au] Autor:Olli KE; Li K; Galileo DS; Martin-DeLeon PA
[Ad] Endereço:Department of Biological Sciences, University of Delaware, Newark, Delaware.
[Ti] Título:Plasma membrane calcium ATPase 4 (PMCA4) co-ordinates calcium and nitric oxide signaling in regulating murine sperm functional activity.
[So] Source:J Cell Physiol;233(1):11-22, 2018 Jan.
[Is] ISSN:1097-4652
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Reduced sperm motility (asthenospermia) and resulting infertility arise from deletion of the Plasma Membrane Ca -ATPase 4 (Pmca4) gene which encodes the highly conserved Ca efflux pump, PMCA4. This is the major Ca clearance protein in murine sperm. Since the mechanism underlying asthenospermia in PMCA4's absence or reduced activity is unknown, we investigated if sperm PMCA4 negatively regulates nitric oxide synthases (NOSs) and when absent NO, peroxynitrite, and oxidative stress levels are increased. Using co-immunoprecipitation (Co-IP) and Fluorescence Resonance Energy Transfer (FRET), we show an association of PMCA4 with the NOSs in elevated cytosolic [Ca ] in capacitated and Ca ionophore-treated sperm and with neuronal (nNOS) at basal [Ca ] (ucapacitated sperm). FRET efficiencies for PMCA4-eNOS were 35% and 23% in capacitated and uncapacitated sperm, significantly (p < 0.01) different, with the molecules being <10 nm apart. For PMCA4-nNOS, this interaction was seen only for capacitated sperm where FRET efficiency was 24%, significantly (p < 0.05) higher than in uncapacitated sperm (6%). PMCA4 and the NOSs were identified as interacting partners in a quaternary complex that includes Caveolin1, which co-immunoprecipitated with eNOS in a Ca -dependent manner. In Pmca4 sperm NOS activity was elevated twofold in capacitated/uncapacitated sperm (vs. wild-type), accompanied by a twofold increase in peroxynitrite levels and significantly (p < 0.001) increased numbers of apoptotic germ cells. The data support a quaternary complex model in which PMCA4 co-ordinates Ca and NO signaling to maintain motility, with increased NO levels resulting in asthenospermia in Pmca4 males. They suggest the involvement of PMCA4 mutations in human asthenospermia, with diagnostic relevance.
[Mh] Termos MeSH primário: Astenozoospermia/enzimologia
Sinalização do Cálcio
ATPases Transportadoras de Cálcio/metabolismo
Membrana Celular/enzimologia
Óxido Nítrico/metabolismo
Motilidade Espermática
Espermatozoides/enzimologia
[Mh] Termos MeSH secundário: Animais
Apoptose
Astenozoospermia/genética
Astenozoospermia/patologia
Astenozoospermia/fisiopatologia
ATPases Transportadoras de Cálcio/deficiência
ATPases Transportadoras de Cálcio/genética
Caveolina 1/metabolismo
Fertilidade
Transferência Ressonante de Energia de Fluorescência
Predisposição Genética para Doença
Masculino
Camundongos Endogâmicos C57BL
Camundongos Endogâmicos ICR
Camundongos Knockout
Complexos Multienzimáticos
Óxido Nítrico Sintase Tipo I/metabolismo
Óxido Nítrico Sintase Tipo III/metabolismo
Estresse Oxidativo
Ácido Peroxinitroso/metabolismo
Fenótipo
Espermatozoides/patologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cav1 protein, mouse); 0 (Caveolin 1); 0 (Multienzyme Complexes); 14691-52-2 (Peroxynitrous Acid); 31C4KY9ESH (Nitric Oxide); EC 1.14.13.39 (Nitric Oxide Synthase Type I); EC 1.14.13.39 (Nitric Oxide Synthase Type III); EC 1.14.13.39 (Nos1 protein, mouse); EC 1.14.13.39 (Nos3 protein, mouse); EC 3.6.3.8 (Calcium-Transporting ATPases); EC 3.6.3.8 (PMCA4 protein, mouse)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:180124
[Lr] Data última revisão:
180124
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170302
[St] Status:MEDLINE
[do] DOI:10.1002/jcp.25882


  7 / 17786 MEDLINE  
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[PMID]:29175388
[Au] Autor:Chen Q; Zheng Y; Luo L; Yang Y; Hu X; Kong X
[Ad] Endereço:Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
[Ti] Título:Functional FRIGIDA allele enhances drought tolerance by regulating the P5CS1 pathway in Arabidopsis thaliana.
[So] Source:Biochem Biophys Res Commun;495(1):1102-1107, 2018 01 01.
[Is] ISSN:1090-2104
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Flowering at the right time is important for the reproductive success of plants and their response to environmental stress. In Arabidopsis, a major determinant of natural variation in flowering time is FRIGIDA (FRI). In the present study, we show that overexpression of the functional FRIGIDA gene in wild-type Col background (ColFRI) positively enhances the drought tolerance by activating P5CS1 expression and promoting proline accumulation during water stress. Furthermore, no significant changes in FRI gene and protein expression levels were observed with drought treatment, whereas P5CS1 protein expression significantly increased. In contrast, vernalization treatment efficiently reduced P5CS1 expression levels and resulted in a decrease in drought tolerance in the ColFRI plants. The flc mutants with a functional FRI background also relieved FRI-mediated activation of P5CS1 during drought tolerance. Taken together, our findings reveal the novel function of FRI in enhancing drought resistance through its downstream P5CS1 pathway during water-deficit stress, which is dependent on its target, the FLC gene.
[Mh] Termos MeSH primário: Proteínas de Arabidopsis/genética
Proteínas de Arabidopsis/metabolismo
Arabidopsis/fisiologia
Secas
Regulação da Expressão Gênica de Plantas/fisiologia
Glutamato-5-Semialdeído Desidrogenase/metabolismo
Redes e Vias Metabólicas/fisiologia
Complexos Multienzimáticos/metabolismo
Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo
Estresse Fisiológico/fisiologia
[Mh] Termos MeSH secundário: Alelos
Flores/genética
Flores/crescimento & desenvolvimento
Glutamato-5-Semialdeído Desidrogenase/genética
Complexos Multienzimáticos/genética
Fosfotransferases (Aceptor do Grupo Álcool)/genética
Plantas Geneticamente Modificadas/fisiologia
Prolina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Arabidopsis Proteins); 0 (FRI protein, Arabidopsis); 0 (Multienzyme Complexes); 0 (delta(1)-pyrroline-5-carboxylate synthetase, Arabidopsis); 9DLQ4CIU6V (Proline); EC 1.2.1.41 (Glutamate-5-Semialdehyde Dehydrogenase); EC 2.7.1.- (Phosphotransferases (Alcohol Group Acceptor))
[Em] Mês de entrada:1712
[Cu] Atualização por classe:180105
[Lr] Data última revisão:
180105
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171128
[St] Status:MEDLINE


  8 / 17786 MEDLINE  
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[PMID]:27770795
[Au] Autor:Liu S; Ding S
[Ad] Endereço:College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China.
[Ti] Título:Replacement of carbohydrate binding modules improves acetyl xylan esterase activity and its synergistic hydrolysis of different substrates with xylanase.
[So] Source:BMC Biotechnol;16(1):73, 2016 10 22.
[Is] ISSN:1472-6750
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Acetylation of the xylan backbone was a major obstacle to enzymatic decomposition. Removal of acetyl groups by acetyl xylan esterases (AXEs) is essential for completely enzymatic hydrolysis of xylan. Appended carbohydrate binding modules (CBMs) can promote the enzymatic deconstruction of plant cell walls by targeting and proximity effects. Fungal acetyl xylan esterases are strictly appended to cellulose-specific CBM1. It is still unclear whether xylan-specific CBMs have a greater advantage than CBM1 in potentiating the activity of fungal deacetylating enzymes and its synergistic hydrolysis of different substrates with xylanase. RESULTS: Three recombinant AXE1s fused with different xylan-specific CBMs, together with wild-type AXE1 with CBM1 and CBM1-deleted mutant AXE1dC, were constructed in this study. The optimal temperature and pH of recombinant AXE1s was 50 °C and 8.0 (except AXE1dC-CBM6), respectively. Cellulose-specific CBM1 in AXE1 obviously contributed to its catalytic action against substrates compared with AXE1dC. However, replacement of CBM1 with xylan-specific CBM4-2 significantly enhanced AXE1 thermostability and catalytic activity against soluble substrate 4-methylumbelliferyl acetate. Whereas replacements with xylan-specific CBM6 and CBM22-2 were more effective in enzymatic release of acetic acid from destarched wheat bran, NaClO -treated wheat straw, and water-insoluble wheat arabinoxylan compared to AXE1. Moreover, replacement with CBM6 and CBM22-2 also resulted in higher degree releases of reducing sugar and acetic acid from different substrates when simultaneous hydrolysis with xylanase. A good linear relationship exists between the acetic acid and reducing sugar release. CONCLUSIONS: Our findings suggested that the replacement with CBM6 and CBM22-2 not only significantly improved the catalysis efficiency of AXE1, but also increased its synergistic hydrolysis of different substrates with xylanase, indicating the significance of targeting effect in AXE1 catalysis mediated by xylan-specific CBMs.
[Mh] Termos MeSH primário: Acetilesterase/química
Acetilesterase/genética
Endo-1,4-beta-Xilanases/química
Endo-1,4-beta-Xilanases/genética
Engenharia de Proteínas/métodos
Xilanos/química
[Mh] Termos MeSH secundário: Acetilação
Carboidratos/genética
Ativação Enzimática/genética
Estabilidade Enzimática
Redes Reguladoras de Genes/genética
Hidrólise
Complexos Multienzimáticos
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Carbohydrates); 0 (Multienzyme Complexes); 0 (Xylans); EC 3.1.1.6 (Acetylesterase); EC 3.1.1.72 (acetylxylan esterase); EC 3.2.1.8 (Endo-1,4-beta Xylanases)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:171226
[Lr] Data última revisão:
171226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE


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[PMID]:28949132
[Au] Autor:Goetzl S; Teutloff C; Werther T; Hennig SE; Jeoung JH; Bittl R; Dobbek H
[Ad] Endereço:Institut für Biologie, Strukturbiologie/Biochemie, Humboldt-Universität zu Berlin , Berlin, Germany.
[Ti] Título:Protein Dynamics in the Reductive Activation of a B12-Containing Enzyme.
[So] Source:Biochemistry;56(41):5496-5502, 2017 Oct 17.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:B12-dependent proteins are involved in methyl transfer reactions ranging from the biosynthesis of methionine in humans to the formation of acetyl-CoA in anaerobic bacteria. During their catalytic cycle, they undergo large conformational changes to interact with various proteins. Recently, the crystal structure of the B12-containing corrinoid iron-sulfur protein (CoFeSP) in complex with its reductive activator (RACo) was determined, providing a first glimpse of how energy is transduced in the ATP-dependent reductive activation of corrinoid-containing methyltransferases. The thermodynamically uphill electron transfer from RACo to CoFeSP is accompanied by large movements of the cofactor-binding domains of CoFeSP. To refine the structure-based mechanism, we analyzed the conformational change of the B12-binding domain of CoFeSP by pulsed electron-electron double resonance and Förster resonance energy transfer spectroscopy. We show that the site-specific labels on the flexible B12-binding domain and the small subunit of CoFeSP move within 11 Å in the RACo:CoFeSP complex, consistent with the recent crystal structures. By analyzing the transient kinetics of formation and dissociation of the RACo:CoFeSP complex, we determined values of 0.75 µM s and 0.33 s for rate constants k and k , respectively. Our results indicate that the large movement observed in crystals also occurs in solution and that neither the formation of the protein encounter complex nor the large movement of the B12-binding domain is rate-limiting for the ATP-dependent reductive activation of CoFeSP by RACo.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Coenzimas/metabolismo
Ativadores de Enzimas/metabolismo
Firmicutes/enzimologia
Proteínas com Ferro-Enxofre/metabolismo
Modelos Moleculares
Vitamina B 12/metabolismo
[Mh] Termos MeSH secundário: Aldeído Oxirredutases/química
Aldeído Oxirredutases/genética
Aldeído Oxirredutases/metabolismo
Substituição de Aminoácidos
Proteínas de Bactérias/química
Proteínas de Bactérias/genética
Coenzimas/química
Cristalografia por Raios X
Bases de Dados de Proteínas
Dimerização
Ativadores de Enzimas/química
Proteínas com Ferro-Enxofre/química
Proteínas com Ferro-Enxofre/genética
Cinética
Complexos Multienzimáticos/química
Complexos Multienzimáticos/genética
Complexos Multienzimáticos/metabolismo
Mutagênese Sítio-Dirigida
Mutação
Oxirredução
Conformação Proteica
Domínios e Motivos de Interação entre Proteínas
Multimerização Proteica
Subunidades Proteicas/química
Subunidades Proteicas/genética
Subunidades Proteicas/metabolismo
Proteínas Recombinantes/química
Proteínas Recombinantes/metabolismo
Solubilidade
Vitamina B 12/química
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Coenzymes); 0 (Enzyme Activators); 0 (Iron-Sulfur Proteins); 0 (Multienzyme Complexes); 0 (Protein Subunits); 0 (Recombinant Proteins); EC 1.2.- (Aldehyde Oxidoreductases); EC 1.2.99.2 (carbon monoxide dehydrogenase); P6YC3EG204 (Vitamin B 12)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171024
[Lr] Data última revisão:
171024
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170927
[St] Status:MEDLINE
[do] DOI:10.1021/acs.biochem.7b00477


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[PMID]:28877996
[Au] Autor:Sobinoff AP; Allen JA; Neumann AA; Yang SF; Walsh ME; Henson JD; Reddel RR; Pickett HA
[Ad] Endereço:Telomere Length Regulation Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW, Australia.
[Ti] Título:BLM and SLX4 play opposing roles in recombination-dependent replication at human telomeres.
[So] Source:EMBO J;36(19):2907-2919, 2017 Oct 02.
[Is] ISSN:1460-2075
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Alternative lengthening of telomeres (ALT) is a telomere lengthening pathway that predominates in aggressive tumors of mesenchymal origin; however, the underlying mechanism of telomere synthesis is not fully understood. Here, we show that the BLM-TOP3A-RMI (BTR) dissolvase complex is required for ALT-mediated telomere synthesis. We propose that recombination intermediates formed during strand invasion are processed by the BTR complex, initiating rapid and extensive POLD3-dependent telomere synthesis followed by dissolution, with no overall exchange of telomeric DNA. This process is counteracted by the SLX4-SLX1-ERCC4 complex, which promotes resolution of the recombination intermediate, resulting in telomere exchange in the absence of telomere extension. Our data are consistent with ALT being a conservative DNA replication process, analogous to break-induced replication, which is dependent on BTR and counteracted by SLX4 complex-mediated resolution events.
[Mh] Termos MeSH primário: Replicação do DNA/genética
RecQ Helicases/fisiologia
Recombinases/fisiologia
Recombinação Genética/genética
Homeostase do Telômero/genética
[Mh] Termos MeSH secundário: Células Cultivadas
DNA Topoisomerases Tipo I/metabolismo
DNA Topoisomerases Tipo I/fisiologia
DNA Polimerase Dirigida por DNA/metabolismo
DNA Polimerase Dirigida por DNA/fisiologia
Seres Humanos
Complexos Multienzimáticos/metabolismo
Complexos Multienzimáticos/fisiologia
RecQ Helicases/metabolismo
Recombinases/metabolismo
Telômero/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Multienzyme Complexes); 0 (Recombinases); EC 2.7.7.- (DNA synthesome); EC 2.7.7.7 (DNA-Directed DNA Polymerase); EC 3.1.- (SLX4 protein, human); EC 3.6.1.- (Bloom syndrome protein); EC 3.6.4.12 (RecQ Helicases); EC 5.99.1.2 (DNA Topoisomerases, Type I); EC 5.99.1.2 (DNA topoisomerase III)
[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:170908
[St] Status:MEDLINE
[do] DOI:10.15252/embj.201796889



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