Base de dados : MEDLINE
Pesquisa : D05.500.562.488.490 [Categoria DeCS]
Referências encontradas : 4155 [refinar]
Mostrando: 1 .. 10   no formato [Detalhado]

página 1 de 416 ir para página                         

  1 / 4155 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29368769
[Au] Autor:Malý P; Gardiner AT; Cogdell RJ; van Grondelle R; Mancal T
[Ad] Endereço:Department of Biophysics, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boeleaan 1081, 1081HV Amsterdam, The Netherlands. p.maly@vu.nl.
[Ti] Título:Robust light harvesting by a noisy antenna.
[So] Source:Phys Chem Chem Phys;20(6):4360-4372, 2018 Feb 07.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Photosynthetic light harvesting can be very efficient in solar energy conversion while taking place in a highly disordered and noisy physiological environment. This efficiency is achieved by the ultrafast speed of the primary photosynthetic processes, which is enabled by a delicate interplay of quantum effects, thermodynamics and environmental noise. The primary processes take place in light-harvesting antennas built from pigments bound to a fluctuating protein scaffold. Here, we employ ultrafast single-molecule spectroscopy to follow fluctuations of the femtosecond energy transfer times in individual LH2 antenna complexes of purple bacteria. By combining single molecule results with ensemble spectroscopy through a unified theoretical description of both, we show how the protein fluctuations alter the excitation energy transfer dynamics. We find that from the thirteen orders of magnitude of possible timescales from picoseconds to minutes, the relevant fluctuations occur predominantly on a biological timescale of seconds, i.e. in the domain of slow protein motion. The measured spectra and dynamics can be explained by the protein modulating pigment excitation energies only. Moreover, we find that the small spread of pigment mean energies allows for excitation delocalization between the coupled pigments to survive. These unique features provide fast energy transport even in the presence of disorder. We conclude that this is the mechanism that enables LH2 to operate as a robust light-harvester, in spite of its intrinsically noisy biological environment.
[Mh] Termos MeSH primário: Complexos de Proteínas Captadores de Luz/química
[Mh] Termos MeSH secundário: Alphaproteobacteria/metabolismo
Transferência de Energia
Complexos de Proteínas Captadores de Luz/metabolismo
Estrutura Quaternária de Proteína
Teoria Quântica
Espectrometria de Fluorescência
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Light-Harvesting Protein Complexes)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180126
[St] Status:MEDLINE
[do] DOI:10.1039/c7cp06139k


  2 / 4155 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29367148
[Au] Autor:Ting JJ
[Ad] Endereço:De-Font Research Institute, Taichung 40344, Taiwan, ROC. Electronic address: juhilian@gmail.com.
[Ti] Título:Proposal for verifying dipole properties of light-harvesting antennas.
[So] Source:J Photochem Photobiol B;179:134-138, 2018 Feb.
[Is] ISSN:1873-2682
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:For light harvesters with a reaction center complex (LH1-RC complex) of three types, we propose an experiment to verify our analysis based upon antenna theories that automatically include the required structural information. Our analysis conforms to the current understanding of light-harvesting antennas in that we can explain known properties of these complexes. We provide an explanation for the functional roles of the notch at the light harvester, a functional role of the polypeptide called PufX or W at the opening, a functional role of the special pair, a reason that the cross section of the light harvester must not be circular, a reason that the light harvester must not be spherical, reasons for the use of dielectric bacteriochlorophylls instead of conductors to make the light harvester, a mechanism to prevent damage from excess sunlight, an advantage of the dimeric form, and reasons for the modular design of nature. Based upon our analysis we provide a mechanism for dimerization. We predict that the dimeric form of light-harvesting complexes is favored under intense sunlight. We further comment upon the classification of the dimeric or S-shape complexes. The S-shape complexes should not be considered as the third type of light harvester but simply as a composite form.
[Mh] Termos MeSH primário: Complexos de Proteínas Captadores de Luz/metabolismo
Modelos Moleculares
[Mh] Termos MeSH secundário: Bacterioclorofilas/química
Bacterioclorofilas/metabolismo
Dimerização
Complexos de Proteínas Captadores de Luz/química
Luz Solar
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacteriochlorophylls); 0 (Light-Harvesting Protein Complexes)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180223
[Lr] Data última revisão:
180223
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180126
[St] Status:MEDLINE


  3 / 4155 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28748638
[Au] Autor:Kawase Y; Imamura S; Tanaka K
[Ad] Endereço:Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan.
[Ti] Título:A MYB-type transcription factor, MYB2, represses light-harvesting protein genes in Cyanidioschyzon merolae.
[So] Source:FEBS Lett;591(16):2439-2448, 2017 08.
[Is] ISSN:1873-3468
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:While searching for transcriptional regulators that respond to changes in light regimes, we identified a MYB domain-containing protein, MYB2, that accumulates under dark and other conditions in the unicellular red alga Cyanidioschyzon merolae. The isolation and analysis of a MYB2 mutant revealed that MYB2 represses the expression of the nuclear-encoded chloroplast RNA polymerase sigma factor gene SIG2, which results in the repression of the chloroplast-encoded phycobilisome genes that are under its control. Since nuclear-encoded phycobilisome and other light-harvesting protein genes are also repressed by MYB2, we conclude that MYB2 has a role in repressing the expression of light-harvesting genes. The MYB2 mutant is sensitive to a prolonged dark incubation, indicating the importance of MYB2 for cell viability in the dark.
[Mh] Termos MeSH primário: Complexos de Proteínas Captadores de Luz/genética
Proteínas de Plantas/metabolismo
Rodófitas/genética
Rodófitas/metabolismo
Fatores de Transcrição/metabolismo
[Mh] Termos MeSH secundário: Núcleo Celular/genética
Núcleo Celular/efeitos da radiação
Escuridão
Regulação da Expressão Gênica de Plantas/efeitos da radiação
Mutação
Regiões Promotoras Genéticas/genética
Rodófitas/citologia
Rodófitas/efeitos da radiação
Análise de Sobrevida
Fatores de Transcrição/genética
[Pt] Tipo de publicação:LETTER; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Light-Harvesting Protein Complexes); 0 (Plant Proteins); 0 (Transcription Factors)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:180220
[Lr] Data última revisão:
180220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170728
[St] Status:MEDLINE
[do] DOI:10.1002/1873-3468.12763


  4 / 4155 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29311621
[Au] Autor:Rätsep M; Muru R; Freiberg A
[Ad] Endereço:Institute of Physics, University of Tartu, W. Ostwald Str. 1, 50411, Tartu, Estonia.
[Ti] Título:High temperature limit of photosynthetic excitons.
[So] Source:Nat Commun;9(1):99, 2018 01 08.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Excitons in light-harvesting complexes are known to significantly improve solar-energy harnessing. Here we demonstrate photosynthetic excitons at super-physiological temperatures reaching 60-80 °C in different species of mesophilic photosynthetic bacteria. It is shown that the survival of light-harvesting excitons in the peripheral LH2 antennae is restricted by thermal decomposition of the pigment-protein complex rather than by any intrinsic property of excitons. The regular spatial organization of the bacteriochlorophyll a pigments supporting excitons in this complex is lost upon the temperature-induced breakdown of its tertiary structure. Secondary structures of the complexes survive even higher temperatures. The discovered pivotal role of the protein scaffold in the stabilization of excitons comprises an important aspect of structure-function relationship in biology. These results also intimately entangle the fundamental issues of quantum mechanical concepts in biology and in the folding of proteins.
[Mh] Termos MeSH primário: Temperatura Alta
Complexos de Proteínas Captadores de Luz/metabolismo
Fotossíntese
Rhodobacter sphaeroides/metabolismo
[Mh] Termos MeSH secundário: Dicroísmo Circular
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Light-Harvesting Protein Complexes)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180212
[Lr] Data última revisão:
180212
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180110
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-02544-7


  5 / 4155 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
[PMID]:29364597
[Au] Autor:Solov'ev AA; Ashikhmin AA; Moskalenko AA
[Ti] Título:Formation of a Subunit Form of the Core Light-Harvesting Complex from Sulfur Purple Bacteria Ectothiorhodospira haloalkaliphila with Different Carotenoid Composition.
[So] Source:Mikrobiologiia;85(5):497-505, 2016 Sep.
[Is] ISSN:0026-3656
[Cp] País de publicação:Russia (Federation)
[La] Idioma:eng
[Ab] Resumo:B820 subunits from a purple sulfur bacterium Ectothiorhodospira. haloalkaliphila strain ATCC 51935T were obtained by treatment of Carotenoid free LH I-RC complexes of this bacterium with P--octylglu- copyranoside (ß-OG). The same complexes with 100% carotenoid content were unable to dissociate to B820 subunits, but disintegrated to monomeric bacteriochlorophyll (BChl) regardless of their carotenoid compo- sition. The degree of dissociation of the LH 1-RC complexes with an intermediate content of carotenoids (the' B820 formation) was directly dependent on the quantity of carotenoids in the samples. The resulting B820 subunits did not contain carotenoids. B820 subunits easily aggregated to form a complex with an absorption . peak at 880 nm at decreased ß-OG concentration. Analysis of the spectra of the LH I-RC complexes isolated from the cells with different'levels of carotenogenesis inhibition led to the conclusion of the heterogeneity of the samples with a predominance in them of (a) the fraction with 100% of carotenoids and (b) the fraction of carotenoid free complexes.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Carotenoides/isolamento & purificação
Chromatiaceae/química
Ectothiorhodospiraceae/química
Complexos de Proteínas Captadores de Luz/química
Subunidades Proteicas/química
[Mh] Termos MeSH secundário: Proteínas de Bactérias/isolamento & purificação
Bacterioclorofilas/química
Bacterioclorofilas/isolamento & purificação
Carotenoides/química
Carotenoides/classificação
Chromatiaceae/metabolismo
Detergentes/química
Ectothiorhodospiraceae/metabolismo
Glucosídeos/química
Complexos de Proteínas Captadores de Luz/isolamento & purificação
Extração Líquido-Líquido/métodos
Agregados Proteicos
Subunidades Proteicas/isolamento & purificação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Bacteriochlorophylls); 0 (Detergents); 0 (Glucosides); 0 (Light-Harvesting Protein Complexes); 0 (Protein Aggregates); 0 (Protein Subunits); 29836-26-8 (octyl-beta-D-glucoside); 36-88-4 (Carotenoids)
[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:180125
[St] Status:MEDLINE


  6 / 4155 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28599858
[Au] Autor:Shalan H; Kato M; Cheruzel L
[Ad] Endereço:San José State University, Department of Chemistry, One Washington Square, San José, CA, United States.
[Ti] Título:Keeping the spotlight on cytochrome P450.
[So] Source:Biochim Biophys Acta;1866(1):80-87, 2018 01.
[Is] ISSN:0006-3002
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:This review describes the recent advances utilizing photosensitizers and visible light to harness the synthetic potential of P450 enzymes. The structures of the photosensitizers investigated to date are first presented along with their photophysical and redox properties. Functional photosensitizers range from organic and inorganic complexes to nanomaterials as well as the biological photosystem I complex. The focus is then on the three distinct approaches that have emerged for the activation of P450 enzymes. The first approach utilizes the in situ generation of reactive oxygen species entering the P450 mechanism via the peroxide shunt pathway. The other two approaches are sustained by electron injections into catalytically competent heme domains either facilitated by redox partners or through direct heme domain reduction. Achievements as well as pitfalls of each approach are briefly summarized. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
[Mh] Termos MeSH primário: Sistema Enzimático do Citocromo P-450/química
Elétrons
Escherichia coli/enzimologia
Heme/química
Complexos de Proteínas Captadores de Luz/química
Fármacos Fotossensibilizantes/química
[Mh] Termos MeSH secundário: Biocatálise
Compostos de Cádmio/química
Sistema Enzimático do Citocromo P-450/metabolismo
Amarelo de Eosina-(YS)/química
Amarelo de Eosina-(YS)/metabolismo
Escherichia coli/química
Escherichia coli/efeitos da radiação
Heme/metabolismo
Luz
Complexos de Proteínas Captadores de Luz/metabolismo
Modelos Moleculares
Oxirredução
Peróxidos/química
Peróxidos/metabolismo
Fármacos Fotossensibilizantes/metabolismo
Estrutura Secundária de Proteína
Pontos Quânticos
Sulfetos/química
Superóxidos/química
Superóxidos/metabolismo
Tioglicolatos/química
Tioglicolatos/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.; REVIEW
[Nm] Nome de substância:
0 (Cadmium Compounds); 0 (Light-Harvesting Protein Complexes); 0 (Peroxides); 0 (Photosensitizing Agents); 0 (Sulfides); 0 (Thioglycolates); 057EZR4Z7Q (cadmium sulfide); 11062-77-4 (Superoxides); 42VZT0U6YR (Heme); 7857H94KHM (2-mercaptoacetate); 9035-51-2 (Cytochrome P-450 Enzyme System); TDQ283MPCW (Eosine Yellowish-(YS))
[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:170611
[St] Status:MEDLINE


  7 / 4155 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29236502
[Au] Autor:Allodi MA; Otto JP; Sohail SH; Saer RG; Wood RE; Rolczynski BS; Massey SC; Ting PC; Blankenship RE; Engel GS
[Ad] Endereço:Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.
[Ti] Título:Redox Conditions Affect Ultrafast Exciton Transport in Photosynthetic Pigment-Protein Complexes.
[So] Source:J Phys Chem Lett;9(1):89-95, 2018 Jan 04.
[Is] ISSN:1948-7185
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Pigment-protein complexes in photosynthetic antennae can suffer oxidative damage from reactive oxygen species generated during solar light harvesting. How the redox environment of a pigment-protein complex affects energy transport on the ultrafast light-harvesting time scale remains poorly understood. Using two-dimensional electronic spectroscopy, we observe differences in femtosecond energy-transfer processes in the Fenna-Matthews-Olson (FMO) antenna complex under different redox conditions. We attribute these differences in the ultrafast dynamics to changes to the system-bath coupling around specific chromophores, and we identify a highly conserved tyrosine/tryptophan chain near the chromophores showing the largest changes. We discuss how the mechanism of tyrosine/tryptophan chain oxidation may contribute to these differences in ultrafast dynamics that can moderate energy transfer to downstream complexes where reactive oxygen species are formed. These results highlight the importance of redox conditions on the ultrafast transport of energy in photosynthesis. Tailoring the redox environment may enable energy transport engineering in synthetic light-harvesting systems.
[Mh] Termos MeSH primário: Complexos de Proteínas Captadores de Luz/química
Fotossíntese
Complexo de Proteínas do Centro de Reação Fotossintética/química
[Mh] Termos MeSH secundário: Transferência de Energia
Luz
Oxirredução
Análise Espectral
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Light-Harvesting Protein Complexes); 0 (Photosynthetic Reaction Center Complex Proteins)
[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:171214
[St] Status:MEDLINE
[do] DOI:10.1021/acs.jpclett.7b02883


  8 / 4155 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28862739
[Au] Autor:Nagao R; Suzuki T; Dohmae N; Shen JR; Tomo T
[Ad] Endereço:Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Japan.
[Ti] Título:Functional role of Lys residues of Psb31 in electrostatic interactions with diatom photosystem II.
[So] Source:FEBS Lett;591(20):3259-3264, 2017 Oct.
[Is] ISSN:1873-3468
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:We recently revealed that positively charged amino acids of Psb31, an extrinsic subunit found in diatom photosystem II (PSII), are involved in electrostatic interactions with PSII intrinsic subunits. However, the molecular interactions of Psb31 with PSII remain unclear. Here, we report the functional contribution of Lys residues in the binding of Psb31 to PSII using site-directed mutants of Psb31. Each of the K33A, K39A, K54A, K56A, K57A, and K69A mutants exhibits decreased binding affinities to PSII concomitantly with decreases in the O evolution activity. Conversely, each of the K24A, K76A, K80A, and K117A mutants functionally binds to PSII in a manner similar to wild-type Psb31. These results provide evidence that some Lys residues of Psb31 are responsible for electrostatic interactions with PSII.
[Mh] Termos MeSH primário: Alanina/química
Diatomáceas/enzimologia
Lisina/química
Complexo de Proteína do Fotossistema II/química
Subunidades Proteicas/química
[Mh] Termos MeSH secundário: Alanina/metabolismo
Sequência de Aminoácidos
Substituição de Aminoácidos
Sítios de Ligação
Clonagem Molecular
Cristalografia por Raios X
Diatomáceas/genética
Escherichia coli/genética
Escherichia coli/metabolismo
Expressão Gênica
Cinética
Complexos de Proteínas Captadores de Luz/química
Complexos de Proteínas Captadores de Luz/metabolismo
Lisina/metabolismo
Modelos Moleculares
Mutação
Complexo de Proteína do Fotossistema II/genética
Complexo de Proteína do Fotossistema II/metabolismo
Ligação Proteica
Domínios e Motivos de Interação entre Proteínas
Estrutura Secundária de Proteína
Subunidades Proteicas/genética
Subunidades Proteicas/metabolismo
Proteínas Recombinantes/química
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Alinhamento de Sequência
Homologia de Sequência de Aminoácidos
Eletricidade Estática
[Pt] Tipo de publicação:LETTER
[Nm] Nome de substância:
0 (Light-Harvesting Protein Complexes); 0 (Photosystem II Protein Complex); 0 (Protein Subunits); 0 (Recombinant Proteins); 127137-94-4 (photosystem II, chlorophyll-binding protein, CP-47); K3Z4F929H6 (Lysine); OF5P57N2ZX (Alanine)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171031
[Lr] Data última revisão:
171031
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170902
[St] Status:MEDLINE
[do] DOI:10.1002/1873-3468.12830


  9 / 4155 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28732060
[Au] Autor:Pathak V; Prasad A; Pospísil P
[Ad] Endereço:Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czech Republic.
[Ti] Título:Formation of singlet oxygen by decomposition of protein hydroperoxide in photosystem II.
[So] Source:PLoS One;12(7):e0181732, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Singlet oxygen (1O2) is formed by triplet-triplet energy transfer from triplet chlorophyll to O2 via Type II photosensitization reaction in photosystem II (PSII). Formation of triplet chlorophyll is associated with the change in spin state of the excited electron and recombination of triplet radical pair in the PSII antenna complex and reaction center, respectively. Here, we have provided evidence for the formation of 1O2 by decomposition of protein hydroperoxide in PSII membranes deprived of Mn4O5Ca complex. Protein hydroperoxide is formed by protein oxidation initiated by highly oxidizing chlorophyll cation radical and hydroxyl radical formed by Type I photosensitization reaction. Under highly oxidizing conditions, protein hydroperoxide is oxidized to protein peroxyl radical which either cyclizes to dioxetane or recombines with another protein peroxyl radical to tetroxide. These highly unstable intermediates decompose to triplet carbonyls which transfer energy to O2 forming 1O2. Data presented in this study show for the first time that 1O2 is formed by decomposition of protein hydroperoxide in PSII membranes deprived of Mn4O5Ca complex.
[Mh] Termos MeSH primário: Clorofila/metabolismo
Peróxido de Hidrogênio/metabolismo
Oxigênio/metabolismo
Complexo de Proteína do Fotossistema II/metabolismo
Oxigênio Singlete/metabolismo
[Mh] Termos MeSH secundário: Espectroscopia de Ressonância de Spin Eletrônica/métodos
Transferência de Energia/fisiologia
Luz
Complexos de Proteínas Captadores de Luz/metabolismo
Oxirredução
Peróxidos/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Light-Harvesting Protein Complexes); 0 (Peroxides); 0 (Photosystem II Protein Complex); 1406-65-1 (Chlorophyll); 17778-80-2 (Singlet Oxygen); 3170-83-0 (perhydroxyl radical); BBX060AN9V (Hydrogen Peroxide); S88TT14065 (Oxygen)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170925
[Lr] Data última revisão:
170925
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170722
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0181732


  10 / 4155 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28657308
[Au] Autor:Saga Y; Hirota K; Asakawa H; Takao K; Fukuma T
[Ad] Endereço:Department of Chemistry, Faculty of Science and Engineering, Kindai University , Higashi-Osaka, Osaka 577-8502, Japan.
[Ti] Título:Reversible Changes in the Structural Features of Photosynthetic Light-Harvesting Complex 2 by Removal and Reconstitution of B800 Bacteriochlorophyll a Pigments.
[So] Source:Biochemistry;56(27):3484-3491, 2017 Jul 11.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Light-harvesting complex 2 (LH2) is an integral membrane protein in purple photosynthetic bacteria. This protein possesses two types of bacteriochlorophyll (BChl) a, termed B800 and B850, which exhibit lowest-energy absorption bands (Q bands) around 800 and 850 nm. These BChl a pigments in the LH2 protein play crucial roles not only in photosynthetic functions but also in folding and maintaining its protein structure. We report herein the reversible structural changes in the LH2 protein derived from a purple photosynthetic bacterium, Rhodoblastus acidophilus, induced by the removal of B800 BChl a (denoted as B800-free LH2) and the reconstitution of exogenous BChl a. Atomic force microscopy observation clearly visualized the nonameric ring structure of the B800-free LH2 with almost the same diameter as the native LH2. Size exclusion chromatography measurements indicated a considerable decrease in the size of the protein induced by the removal of B800 BChl a. The protein size was almost recovered by the insertion of BChl a pigments into the B800 binding sites. The decrease in the LH2 size would mainly originate from the shrinkage of the B800 binding sites perpendicular to the macrocycle of B800 BChl a without deformation of the circular arrangement. The reversible changes in the LH2 structure induced by the removal and reconstitution of B800 BChl a will be helpful for understanding the structural principle and the folding mechanism of photosynthetic pigment-protein complexes.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Bacterioclorofila A/metabolismo
Complexos de Proteínas Captadores de Luz/metabolismo
Modelos Moleculares
Pigmentos Biológicos/metabolismo
Rhodobacter sphaeroides/metabolismo
Rodopseudomonas/enzimologia
[Mh] Termos MeSH secundário: Proteínas de Bactérias/química
Proteínas de Bactérias/isolamento & purificação
Bacterioclorofila A/química
Bacterioclorofila A/isolamento & purificação
Sítios de Ligação
Cromatografia em Gel
Dicroísmo Circular
Concentração de Íons de Hidrogênio
Complexos de Proteínas Captadores de Luz/química
Complexos de Proteínas Captadores de Luz/isolamento & purificação
Microscopia de Força Atômica
Peso Molecular
Pigmentos Biológicos/química
Pigmentos Biológicos/isolamento & purificação
Conformação Proteica
Dobramento de Proteína
Multimerização Proteica
Estrutura Quaternária de Proteína
Espectrofotometria Ultravioleta
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (B800-850 light-harvesting complex, bacteria); 0 (Bacterial Proteins); 0 (Bacteriochlorophyll A); 0 (Light-Harvesting Protein Complexes); 0 (Pigments, Biological)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170726
[Lr] Data última revisão:
170726
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170629
[St] Status:MEDLINE
[do] DOI:10.1021/acs.biochem.7b00267



página 1 de 416 ir para página                         
   


Refinar a pesquisa
  Base de dados : MEDLINE Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde