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[PMID]:28985484
[Au] Autor:Abate-Pella D; Freund DM; Slovin JP; Hegeman AD; Cohen JD
[Ad] Endereço:Department of Horticultural Science, University of Minnesota, Saint Paul, MN, USA; Microbial and Plant Genomics Institute, University of Minnesota, Saint Paul, MN, USA.
[Ti] Título:An improved method for fast and selective separation of carotenoids by LC-MS.
[So] Source:J Chromatogr B Analyt Technol Biomed Life Sci;1067:34-37, 2017 Nov 01.
[Is] ISSN:1873-376X
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Carotenoids are a large class of compounds that are biosynthesized by condensation of isoprene units in plants, fungi, bacteria, and some animals. They are characteristically highly conjugated through double bonds, which lead to many isomers as well susceptibility to oxidation and other chemical modifications. Carotenoids are important because of their potent antioxidant activity and are the pigments responsible for color in a wide variety of foods. Human consumption is correlated to many health benefits including prevention of cancer, cardiovascular disease, and age-related disease. Extreme hydrophobicity, poor stability, and low concentration in biological samples make these compounds difficult to analyze and difficult to develop analytical methods for aimed towards identification and quantification. Examples in the literature frequently report the use of exotic stationary phases, solvents, and additives, such as ethyl acetate, dichloromethane, and methyl tert-butyl ether that are incompatible with liquid chromatography mass spectrometry (LC-MS). In order to address these issues, we implemented the use of LC-MS friendly conditions using a low-hydrophobicity cyano-propyl column (Agilent Zorbax SB-CN). We successfully differentiated between isomeric carotenoids by optimizing two gradient methods and using a mixture of 11 standards and LC-MS in positive ionization mode. Three complex biological samples from strawberry leaf, chicken feed supplement, and the photosynthetic bacterium Chloroflexus aurantiacus were analyzed and several carotenoids were resolved in these diverse backgrounds. Our results show this methodology is a significant improvement over other alternatives for analyzing carotenoids because of its ease of use, rapid analysis time, high selectivity, and, most importantly, its compatibility with typical LC-MS conditions.
[Mh] Termos MeSH primário: Carotenoides/análise
Carotenoides/isolamento & purificação
Cromatografia Líquida/métodos
Espectrometria de Massas/métodos
[Mh] Termos MeSH secundário: Ração Animal/análise
Carotenoides/química
Chloroflexus/química
Fragaria/química
Isomerismo
Modelos Químicos
Folhas de Planta/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
36-88-4 (Carotenoids)
[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:171007
[St] Status:MEDLINE


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[PMID]:28126046
[Au] Autor:Gaisin VA; Kalashnikov AM; Grouzdev DS; Sukhacheva MV; Kuznetsov BB; Gorlenko VM
[Ad] Endereço:Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2. Leninsky Ave., Moscow 119071, Russian Federation.
[Ti] Título:Chloroflexus islandicus sp. nov., a thermophilic filamentous anoxygenic phototrophic bacterium from a geyser.
[So] Source:Int J Syst Evol Microbiol;67(5):1381-1386, 2017 May.
[Is] ISSN:1466-5034
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:A novel, thermophilic filamentous anoxygenic phototrophic bacterium, strain isl-2T, was isolated from the Strokkur Geyser, Iceland. Strain isl-2T formed unbranched multicellular filaments with gliding motility. The cells formed no spores and stained Gram-negative. The existence of pili was described in a species of the genus Chloroflexus for the first time, to our knowledge. Optimal growth occurred at a pH range of 7.5-7.7 and at a temperature of 55 °C. Strain isl-2T grew photoheterotrophically under anaerobic conditions in the light and chemoheterotrophically under aerobic conditions in the dark. The major cellular fatty acids were C18 : 1ω9, C16 : 0, C18 : 0 and C18 : 0-OH. The major quinone was menaquinone-10. The photosynthetic pigments were bacteriochlorophylls c and a as well as ß- and γ-carotenes. The results of phylogenetic analysis of the 16S rRNA gene sequences placed strain isl-2T into the genus Chloroflexus of the phylum Chloroflexi with Chloroflexus aggregans DSM 9485T as the closest relative (97.0 % identity). The whole-genome sequence of isl-2T was determined. Average nucleotide identity values obtained for isl-2T in comparison to available genomic sequences of other strains of members of the genus Chloroflexus were 81.4 % or less and digital DNA-DNA hybridisation values 22.8 % or less. The results of additional phylogenetic analysis of the PufLM and BchG amino acid sequences supported the separate position of the isl-2T phylotype from the phylotypes of other members of the genus Chloroflexus. On the basis of physiological and phylogenetic data as well as genomic data, it was suggested that isl-2T represents a novel species within the genus Chloroflexus, with the proposed name Chloroflexus islandicus sp. nov. The type strain of the species is isl-2T (=VKM B-2978T,=DSM 29225T,=JCM 30533T).
[Mh] Termos MeSH primário: Chloroflexus/classificação
Filogenia
Microbiologia da Água
[Mh] Termos MeSH secundário: Proteínas de Bactérias/química
Técnicas de Tipagem Bacteriana
Bacterioclorofilas/química
Composição de Bases
Carotenoides/química
Chloroflexus/genética
Chloroflexus/isolamento & purificação
DNA Bacteriano/genética
Ácidos Graxos/química
Islândia
Hibridização de Ácido Nucleico
RNA Ribossômico 16S/genética
Análise de Sequência de DNA
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Bacteriochlorophylls); 0 (DNA, Bacterial); 0 (Fatty Acids); 0 (RNA, Ribosomal, 16S); 36-88-4 (Carotenoids); 53986-51-9 (bacteriochlorophyll c)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170825
[Lr] Data última revisão:
170825
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170128
[St] Status:MEDLINE
[do] DOI:10.1099/ijsem.0.001820


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[PMID]:26980206
[Au] Autor:Kildegaard KR; Jensen NB; Schneider K; Czarnotta E; Özdemir E; Klein T; Maury J; Ebert BE; Christensen HB; Chen Y; Kim IK; Herrgård MJ; Blank LM; Forster J; Nielsen J; Borodina I
[Ad] Endereço:The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, 2970, Hørsholm, Denmark.
[Ti] Título:Engineering and systems-level analysis of Saccharomyces cerevisiae for production of 3-hydroxypropionic acid via malonyl-CoA reductase-dependent pathway.
[So] Source:Microb Cell Fact;15:53, 2016 Mar 15.
[Is] ISSN:1475-2859
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: In the future, oil- and gas-derived polymers may be replaced with bio-based polymers, produced from renewable feedstocks using engineered cell factories. Acrylic acid and acrylic esters with an estimated world annual production of approximately 6 million tons by 2017 can be derived from 3-hydroxypropionic acid (3HP), which can be produced by microbial fermentation. For an economically viable process 3HP must be produced at high titer, rate and yield and preferably at low pH to minimize downstream processing costs. RESULTS: Here we describe the metabolic engineering of baker's yeast Saccharomyces cerevisiae for biosynthesis of 3HP via a malonyl-CoA reductase (MCR)-dependent pathway. Integration of multiple copies of MCR from Chloroflexus aurantiacus and of phosphorylation-deficient acetyl-CoA carboxylase ACC1 genes into the genome of yeast increased 3HP titer fivefold in comparison with single integration. Furthermore we optimized the supply of acetyl-CoA by overexpressing native pyruvate decarboxylase PDC1, aldehyde dehydrogenase ALD6, and acetyl-CoA synthase from Salmonella enterica SEacs (L641P). Finally we engineered the cofactor specificity of the glyceraldehyde-3-phosphate dehydrogenase to increase the intracellular production of NADPH at the expense of NADH and thus improve 3HP production and reduce formation of glycerol as by-product. The final strain produced 9.8 ± 0.4 g L(-1) 3HP with a yield of 13% C-mol C-mol(-1) glucose after 100 h in carbon-limited fed-batch cultivation at pH 5. The 3HP-producing strain was characterized by (13)C metabolic flux analysis and by transcriptome analysis, which revealed some unexpected consequences of the undertaken metabolic engineering strategy, and based on this data, future metabolic engineering directions are proposed. CONCLUSIONS: In this study, S. cerevisiae was engineered for high-level production of 3HP by increasing the copy numbers of biosynthetic genes and improving flux towards precursors and redox cofactors. This strain represents a good platform for further optimization of 3HP production and hence an important step towards potential commercial bio-based production of 3HP.
[Mh] Termos MeSH primário: Ácido Láctico/análogos & derivados
Engenharia Metabólica/métodos
Oxirredutases/metabolismo
Saccharomyces cerevisiae
[Mh] Termos MeSH secundário: Chloroflexus/enzimologia
Chloroflexus/genética
Regulação Fúngica da Expressão Gênica
Ácido Láctico/biossíntese
Redes e Vias Metabólicas
Organismos Geneticamente Modificados
Oxirredução
Oxirredutases/genética
Saccharomyces cerevisiae/genética
Saccharomyces cerevisiae/metabolismo
Salmonella enterica/enzimologia
Salmonella enterica/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
33X04XA5AT (Lactic Acid); C4ZF6XLD2X (hydracrylic acid); EC 1.- (Oxidoreductases); EC 1.- (malonyl-Coa reductase)
[Em] Mês de entrada:1702
[Cu] Atualização por classe:170223
[Lr] Data última revisão:
170223
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160317
[St] Status:MEDLINE
[do] DOI:10.1186/s12934-016-0451-5


  4 / 92 MEDLINE  
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[PMID]:26669591
[Au] Autor:Anderson LN; Koech PK; Plymale AE; Landorf EV; Konopka A; Collart FR; Lipton MS; Romine MF; Wright AT
[Ad] Endereço:Biological Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352 United States.
[Ti] Título:Live Cell Discovery of Microbial Vitamin Transport and Enzyme-Cofactor Interactions.
[So] Source:ACS Chem Biol;11(2):345-54, 2016 Feb 19.
[Is] ISSN:1554-8937
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The rapid completion of microbial genomes is inducing a conundrum in functional gene discovery. Novel methods are needed to shorten the gap between characterizing a microbial genome and experimentally validating bioinformatically predicted functions. Of particular importance are transport mechanisms, which shuttle nutrients such as B vitamins and metabolites across cell membranes and are required for the survival of microbes ranging from members of environmental microbial communities to pathogens. Methods to accurately assign function and specificity for a wide range of experimentally unidentified and/or predicted membrane-embedded transport proteins, along with characterization of intracellular enzyme-cofactor associations, are needed to enable a significantly improved understanding of microbial biochemistry and physiology, microbial interactions, and microbial responses to perturbations. Chemical probes derived from B vitamins B1, B2, and B7 have allowed us to experimentally address the aforementioned needs by identifying B vitamin transporters and intracellular enzyme-cofactor associations through live cell labeling of the filamentous anoxygenic photoheterotroph, Chloroflexus aurantiacus J-10-fl, known to employ mechanisms for both B vitamin biosynthesis and environmental salvage. Our probes provide a unique opportunity to directly link cellular activity and protein function back to ecosystem and/or host dynamics by identifying B vitamin transport and cofactor-dependent interactions required for survival.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Chloroflexus/metabolismo
Complexo Vitamínico B/metabolismo
[Mh] Termos MeSH secundário: Transporte Biológico
Chloroflexus/citologia
Técnicas de Sonda Molecular
Imagem Óptica
Proteoma/metabolismo
Coloração e Rotulagem
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Proteome); 12001-76-2 (Vitamin B Complex)
[Em] Mês de entrada:1610
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:151217
[St] Status:MEDLINE
[do] DOI:10.1021/acschembio.5b00918


  5 / 92 MEDLINE  
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[PMID]:26290358
[Au] Autor:Gaisin VA; Kalashnikov AM; Sukhacheva MV; Namsaraev ZB; Barhutova DD; Gorlenko VM; Kuznetsov BB
[Ad] Endereço:Centre Bioengineering RAS, Prospekt 60-Letiya Oktyabrya, 7/1, 117312, Moscow, Russia. vasil.beingi@gmail.com.
[Ti] Título:Filamentous anoxygenic phototrophic bacteria from cyanobacterial mats of Alla hot springs (Barguzin Valley, Russia).
[So] Source:Extremophiles;19(6):1067-76, 2015 Nov.
[Is] ISSN:1433-4909
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Alkaline hydrotherms of the Baikal rift zone are unique systems to study the diversity of thermophilic bacteria. In this study, we present data on the phototrophic bacterial community of cyanobacterial mats from the alkaline Alla hot spring. Using a clonal analysis approach, this study evaluated the species diversity, the proportion of oxygenic and anoxygenic phototrophs and their distribution between various areas of the spring. Novel group-specific PCR primers were designed and applied to detect representatives of the Chloroflexus and Roseiflexus genera in mat samples. For the first time, the presence of Roseiflexus-like bacteria was detected in the Baikal rift zone.
[Mh] Termos MeSH primário: Chloroflexus/isolamento & purificação
Fontes Termais/microbiologia
[Mh] Termos MeSH secundário: Chloroflexus/classificação
Chloroflexus/genética
Cianobactérias/genética
Cianobactérias/isolamento & purificação
Filogenia
Sibéria
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1608
[Cu] Atualização por classe:171013
[Lr] Data última revisão:
171013
[Sb] Subgrupo de revista:IM; S
[Da] Data de entrada para processamento:150821
[St] Status:MEDLINE
[do] DOI:10.1007/s00792-015-0777-7


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[PMID]:25673656
[Au] Autor:Morohoshi S; Matsuura K; Haruta S
[Ad] Endereço:Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
[Ti] Título:Secreted protease mediates interspecies interaction and promotes cell aggregation of the photosynthetic bacterium Chloroflexus aggregans.
[So] Source:FEMS Microbiol Lett;362(3):1-5, 2015 Jan.
[Is] ISSN:1574-6968
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Interspecies interactions were studied in hot spring microbial mats where diverse species of bacterial cells are densely packed. The anoxygenic photosynthetic bacterium, Chloroflexus aggregans, has been widely found in the microbial mats as a major component in terrestrial hot springs in Japan at the temperature from 50 to 70°C. C. aggregans shows cellular motility to form a microbial mat-like dense cell aggregate. The aggregating ability of C. aggregans was affected by another bacterial species, strain BL55a (related to Bacillus licheniformis) isolated from the microbial mats containing C. aggregans. Cell aggregation rate of C. aggregans was promoted by the addition of culture supernatants of strain BL55a. Similar effects were also detected from other bacterial isolates, specifically Geobacillus sp. and Aeribacillus sp. Protease activity was detected from the culture supernatants from all of these isolates. The promoting effect of strain BL55a was suppressed by a serine protease inhibitor, phenylmethylsulfonyl fluoride. A purified serine protease, subtilisin obtained from B. licheniformis, showed a promoting effect on the cell aggregation. These results suggest that an extracellular protease, secreted from co-existing bacterial species promoted the aggregating motility of C. aggregans. This is the first report that exogenous protease affects bacterial cellular motility.
[Mh] Termos MeSH primário: Bacillus/enzimologia
Chloroflexus/fisiologia
Fontes Termais/microbiologia
Interações Microbianas
Peptídeo Hidrolases/metabolismo
[Mh] Termos MeSH secundário: Bacillus/genética
Bacillus/isolamento & purificação
Bacillus/fisiologia
Chloroflexus/genética
Chloroflexus/isolamento & purificação
Geobacillus/genética
Geobacillus/isolamento & purificação
Geobacillus/fisiologia
Japão
Peptídeo Hidrolases/isolamento & purificação
Fluoreto de Fenilmetilsulfonil/farmacologia
Fotossíntese
Inibidores de Proteases/farmacologia
RNA Ribossômico 16S
Análise de Sequência de DNA
Subtilisina/biossíntese
Subtilisina/isolamento & purificação
Subtilisina/metabolismo
Temperatura Ambiente
Microbiologia da Água
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Protease Inhibitors); 0 (RNA, Ribosomal, 16S); 57KD15003I (Phenylmethylsulfonyl Fluoride); EC 3.4.- (Peptide Hydrolases); EC 3.4.21.62 (Subtilisin)
[Em] Mês de entrada:1510
[Cu] Atualização por classe:150212
[Lr] Data última revisão:
150212
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150213
[St] Status:MEDLINE
[do] DOI:10.1093/femsle/fnu046


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[PMID]:25515768
[Au] Autor:Yakovlev A; Novoderezhkin V; Taisova A; Shuvalov V; Fetisova Z
[Ad] Endereço:Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 119991, Moscow, Russian Federation.
[Ti] Título:Orientation of B798 BChl a Q y transition dipoles in Chloroflexus aurantiacus chlorosomes: polarized transient absorption spectroscopy studies.
[So] Source:Photosynth Res;125(1-2):31-42, 2015 Aug.
[Is] ISSN:1573-5079
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Isotropic and anisotropic pump-probe spectra of Cfx. aurantiacus chlorosomes were measured on the fs-through ps-time scales for the B798 BChl a Q y band upon direct excitation of the B798 band at T = 293 K and T = 90 K. Upon direct excitation of the B798 band, the anisotropy parameter value r(λ) was constant within the whole BChl a Q y band at any delay time at both temperatures. The value of the anisotropy parameter r decayed from r = 0.4 at both temperatures (at 200 fs delay time after excitation) to the steady-state values r = 0.1 at T = 293 K and to r = 0.09 at T = 90 K (at 30 ÷ 100 ps delay time after excitation). The results were considered within the framework of the model of uniaxial orientation distribution of BChl-a transition dipoles within a single Cfx. aurantiacus chlorosome. This implies that the B798 BChl a Q y transition dipoles, randomly distributed around the normal to the baseplate plane, form the angle θ with the plane. For this model, the theoretical dependence of the steady-state anisotropy parameter r on the angle θ was derived. According to the theoretical dependence r(θ), the angle θ corresponding to the experimental steady-state value r = 0.1 at T = 293 K was found to equal 55°. As the temperature drops to 90 K, the angle θ decreases to 54°.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Chloroflexus/metabolismo
Organelas/metabolismo
[Mh] Termos MeSH secundário: Anisotropia
Proteínas de Bactérias/química
Polarização de Fluorescência
Espectrometria de Fluorescência
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (bacteriochlorophyll A proteins, Bacteria)
[Em] Mês de entrada:1605
[Cu] Atualização por classe:171101
[Lr] Data última revisão:
171101
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141218
[St] Status:MEDLINE
[do] DOI:10.1007/s11120-014-0060-2


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[PMID]:25526209
[Au] Autor:Zhang HX; Li SJ; Zhou HQ
[Ad] Endereço:School of Life Science and Technology, Key Laboratory for Neuroinformation of Ministry of Education, University of Electronic Science and Technology of China, Chengdu, China johnzhangchina2007@gmail.com.
[Ti] Título:Evaluating the annotation of protein-coding genes in bacterial genomes: Chloroflexus aurantiacus strain J-10-fl and Natrinema sp J7-2 as case studies.
[So] Source:Genet Mol Res;13(4):10891-7, 2014 Dec 19.
[Is] ISSN:1676-5680
[Cp] País de publicação:Brazil
[La] Idioma:eng
[Ab] Resumo:Gene annotation plays a key role in subsequent biochemical and molecular biological studies of various organisms. There are some errors in the original annotation of sequenced genomes because of the lack of sufficient data, and these errors may propagate into other genomes. Therefore, genome annotation must be checked from time to time to evaluate newly accumulated data. In this study, we evaluated the gene density of 2606 bacteria or archaea, and identified 2 with extreme values, the minimum value (Chloroflexus aurantiacus strain J-10-fl) and maximum value (Natrinema sp J7-2), to conduct genome re-annotation. In the genome of C. aurantiacus strain J-10-fl, we identified 17 new genes with definite functions and eliminated 34 non-coding open-reading frames; in the genome of Natrinema sp J7-2, we eliminated 118 non-coding open reading frames. Our re-annotation procedure may provide a reference for improving the annotation of other bacterial genomes.
[Mh] Termos MeSH primário: Chloroflexus/genética
Halobacteriaceae/genética
Anotação de Sequência Molecular/métodos
[Mh] Termos MeSH secundário: Proteínas Arqueais/genética
Proteínas de Bactérias/genética
Chloroflexus/classificação
Tamanho do Genoma
Genoma Arqueal
Genoma Bacteriano
Halobacteriaceae/classificação
Análise de Sequência de DNA
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Archaeal Proteins); 0 (Bacterial Proteins)
[Em] Mês de entrada:1508
[Cu] Atualização por classe:141220
[Lr] Data última revisão:
141220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141220
[St] Status:MEDLINE
[do] DOI:10.4238/2014.December.19.10


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[PMID]:25437494
[Au] Autor:Kalimeri M; Girard E; Madern D; Sterpone F
[Ad] Endereço:Laboratoire de Biochimie Théorique, Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique, UPR9080, Univ. Paris Diderot, Sorbonne Paris Cité, Paris, France.
[Ti] Título:Interface matters: the stiffness route to stability of a thermophilic tetrameric malate dehydrogenase.
[So] Source:PLoS One;9(12):e113895, 2014.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In this work we investigate by computational means the behavior of two orthologous bacterial proteins, a mesophilic and a thermophilic tetrameric malate dehydrogenase (MalDH), at different temperatures. Namely, we quantify how protein mechanical rigidity at different length- and time-scales correlates to protein thermophilicity as commonly believed. In particular by using a clustering analysis strategy to explore the conformational space of the folded proteins, we show that at ambient conditions and at the molecular length-scale the thermophilic variant is indeed more rigid that the mesophilic one. This rigidification is the result of more efficient inter-domain interactions, the strength of which is further quantified via ad hoc free energy calculations. When considered isolated, the thermophilic domain is indeed more flexible than the respective mesophilic one. Upon oligomerization, the induced stiffening of the thermophilic protein propagates from the interface to the active site where the loop, controlling the access to the catalytic pocket, anchors down via an extended network of ion-pairs. On the contrary in the mesophilic tetramer the loop is highly mobile. Simulations at high temperature, could not re-activate the mobility of the loop in the thermophile. This finding opens questions on the similarities of the binding processes for these two homologues at their optimal working temperature and suggests for the thermophilic variant a possible cooperative role of cofactor/substrate.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Chlorobium/enzimologia
Chloroflexus/enzimologia
Malato Desidrogenase/química
[Mh] Termos MeSH secundário: Domínio Catalítico
Análise por Conglomerados
Cristalografia por Raios X
Estabilidade Enzimática
Modelos Moleculares
Simulação de Dinâmica Molecular
Multimerização Proteica
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); EC 1.1.1.37 (Malate Dehydrogenase)
[Em] Mês de entrada:1509
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:141202
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0113895


  10 / 92 MEDLINE  
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[PMID]:24880610
[Au] Autor:Wang Y; Freund DM; Magdaong NM; Urban VS; Frank HA; Hegeman AD; Tang JK
[Ad] Endereço:Department of Chemistry and Biochemistry, Clark University, Worcester, MA, 01610, USA.
[Ti] Título:Impact of esterified bacteriochlorophylls on the biogenesis of chlorosomes in Chloroflexus aurantiacus.
[So] Source:Photosynth Res;122(1):69-86, 2014 Oct.
[Is] ISSN:1573-5079
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:A chlorosome is an antenna complex located on the cytoplasmic side of the inner membrane in green photosynthetic bacteria that contains tens of thousands of self-assembled bacteriochlorophylls (BChls). Green bacteria are known to incorporate various esterifying alcohols at the C-17 propionate position of BChls in the chlorosome. The effect of these functional substitutions on the biogenesis of the chlorosome has not yet been fully explored. In this report, we address this question by investigating various esterified bacteriochlorophyll c (BChl c) homologs in the thermophilic green non-sulfur bacterium Chloroflexus aurantiacus. Cultures were supplemented with exogenous long-chain alcohols at 52 °C (an optimal growth temperature) and 44 °C (a suboptimal growth temperature), and the morphology, optical properties and exciton transfer characteristics of chlorosomes were investigated. Our studies indicate that at 44 °C Cfl. aurantiacus synthesizes more carotenoids, incorporates more BChl c homologs with unsaturated and rigid polyisoprenoid esterifying alcohols and produces more heterogeneous BChl c homologs in chlorosomes. Substitution of phytol for stearyl alcohol of BChl c maintains similar morphology of the intact chlorosome and enhances energy transfer from the chlorosome to the membrane-bound photosynthetic apparatus. Different morphologies of the intact chlorosome versus in vitro BChl aggregates are suggested by small-angle neutron scattering. Additionally, phytol cultures and 44 °C cultures exhibit slow assembly of the chlorosome. These results suggest that the esterifying alcohol of BChl c contributes to long-range organization of BChls, and that interactions between BChls with other components are important to the assembly of the chlorosome. Possible mechanisms for how esterifying alcohols affect the biogenesis of the chlorosome are discussed.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Bacterioclorofilas/química
Chloroflexus/química
Organelas/metabolismo
Ficobiliproteínas/química
[Mh] Termos MeSH secundário: Álcoois/metabolismo
Proteínas de Bactérias/metabolismo
Bacterioclorofilas/metabolismo
Carotenoides/metabolismo
Chloroflexus/fisiologia
Cromatografia Líquida
Transferência de Energia
Esterificação
Organelas/química
Ficobiliproteínas/metabolismo
Espectrometria de Massas em Tandem
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Alcohols); 0 (Bacterial Proteins); 0 (Bacteriochlorophylls); 0 (Phycobiliproteins); 36-88-4 (Carotenoids); 53986-51-9 (bacteriochlorophyll c)
[Em] Mês de entrada:1506
[Cu] Atualização por classe:171101
[Lr] Data última revisão:
171101
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140602
[St] Status:MEDLINE
[do] DOI:10.1007/s11120-014-0017-5



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