Base de dados : MEDLINE
Pesquisa : D02.047.850 [Categoria DeCS]
Referências encontradas : 2139 [refinar]
Mostrando: 1 .. 10   no formato [Detalhado]

página 1 de 214 ir para página                         

  1 / 2139 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29358689
[Au] Autor:Gueye M; Manathunga M; Agathangelou D; Orozco Y; Paolino M; Fusi S; Haacke S; Olivucci M; Léonard J
[Ad] Endereço:Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67034, Strasbourg, France.
[Ti] Título:Engineering the vibrational coherence of vision into a synthetic molecular device.
[So] Source:Nat Commun;9(1):313, 2018 01 22.
[Is] ISSN:2041-1723
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The light-induced double-bond isomerization of the visual pigment rhodopsin operates a molecular-level optomechanical energy transduction, which triggers a crucial protein structure change. In fact, rhodopsin isomerization occurs according to a unique, ultrafast mechanism that preserves mode-specific vibrational coherence all the way from the reactant excited state to the primary photoproduct ground state. The engineering of such an energy-funnelling function in synthetic compounds would pave the way towards biomimetic molecular machines capable of achieving optimum light-to-mechanical energy conversion. Here we use resonance and off-resonance vibrational coherence spectroscopy to demonstrate that a rhodopsin-like isomerization operates in a biomimetic molecular switch in solution. Furthermore, by using quantum chemical simulations, we show why the observed coherent nuclear motion critically depends on minor chemical modifications capable to induce specific geometric and electronic effects. This finding provides a strategy for engineering vibrationally coherent motions in other synthetic systems.
[Mh] Termos MeSH primário: Materiais Biomiméticos/química
Indanos/química
Dispositivos Ópticos
Pirróis/química
Retinaldeído/química
Rodopsina/química
[Mh] Termos MeSH secundário: Alquilação
Animais
Materiais Biomiméticos/síntese química
Engenharia Química
Seres Humanos
Indanos/síntese química
Luz
Processos Fotoquímicos
Pirróis/síntese química
Teoria Quântica
Análise Espectral/instrumentação
Análise Espectral/métodos
Vibração
Visão Ocular/fisiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Indans); 0 (Pyrroles); 9009-81-8 (Rhodopsin); RR725D715M (Retinaldehyde)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180222
[Lr] Data última revisão:
180222
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180124
[St] Status:MEDLINE
[do] DOI:10.1038/s41467-017-02668-w


  2 / 2139 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
[PMID]:28900371
[Au] Autor:Hanneken A; Neikirk T; Johnson J; Kono M
[Ad] Endereço:Department of Molecular Medicine, The Scripps Research Institute, SP-202, 10550 North Torrey Pines Road, La Jolla, CA 92037 (Drs. Hanneken, Neikirk, Johnson). Department of Ophthalmology, Medical University of South Carolina, Charleston, SC (Dr. Kono).
[Ti] Título:Biochemical Measurements of Free Opsin in Macular Degeneration Eyes: Examining the 11- Retinal Deficiency Hypothesis of Delayed Dark Adaptation (An American Ophthalmological Society Thesis).
[So] Source:Trans Am Ophthalmol Soc;115:T1, 2017 Aug.
[Is] ISSN:1545-6110
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To test the hypothesis that delayed dark adaptation in patients with macular degeneration is due to an excess of free unliganded opsin (apo-opsin) and a deficiency of the visual chromophore, 11 retinal, in rod outer segments. METHODS: A total of 50 human autopsy eyes were harvested from donors with and without macular degeneration within 2-24 hrs. postmortem. Protocols were developed which permitted dark adaptation of normal human eyes after death and enucleation. Biochemical methods of purifying rod outer segments were optimized and the concentration of rhodopsin and apo-opsin was measured with UV-visible scanning spectroscopy. The presence of apo-opsin was calculated by measuring the difference in the rhodopsin absorption spectra before and after the addition of 11 retinal. RESULTS: A total of 20 normal eyes and 16 eyes from donors with early, intermediate and advanced stages of macular degeneration were included in the final analysis. Dark adaptation was achieved by harvesting whole globes in low light, transferring into dark (light-proof) canisters and dissecting the globes using infrared light and image converters for visualization. Apo-opsin was readily detected in positive controls after the addition of 11 retinal. Normal autopsy eyes showed no evidence of apo-opsin. Eyes with macular degeneration also showed no evidence of apo-opsin, regardless of the severity of disease. CONCLUSIONS: Methods have been developed to study dark adaptation in human autopsy eyes. Eyes with age-related macular degeneration do not show a deficiency of 11 retinal or an excess of apo-opsin within rod outer segments.
[Mh] Termos MeSH primário: Consenso
Adaptação à Escuridão/fisiologia
Degeneração Macular/fisiopatologia
Oftalmologia
Opsinas/metabolismo
Retinaldeído/deficiência
Sociedades Médicas
[Mh] Termos MeSH secundário: Seres Humanos
Degeneração Macular/metabolismo
Segmento Externo da Célula Bastonete/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Opsins); RR725D715M (Retinaldehyde)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170929
[Lr] Data última revisão:
170929
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170914
[St] Status:MEDLINE


  3 / 2139 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28784816
[Au] Autor:Peck RF; Plesa AM; Graham SM; Angelini DR; Shaw EL
[Ad] Endereço:Department of Biology, Colby College, Waterville, Maine, USA ronald.peck@colby.edu.
[Ti] Título:Opsin-Mediated Inhibition of Bacterioruberin Synthesis in Halophilic Archaea.
[So] Source:J Bacteriol;199(21), 2017 Nov 01.
[Is] ISSN:1098-5530
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Halophilic archaea often inhabit environments with limited oxygen, and many produce ion-pumping rhodopsin complexes that allow them to maintain electrochemical gradients when aerobic respiration is inhibited. Rhodopsins require a protein, an opsin, and an organic cofactor, retinal. We previously demonstrated that in , bacterioopsin (BO), when not bound by retinal, inhibits the production of bacterioruberin, a biochemical pathway that shares intermediates with retinal biosynthesis. In this work, we used heterologous expression in a related halophilic archaeon, , to demonstrate that BO is sufficient to inhibit bacterioruberin synthesis catalyzed by the lycopene elongase (Lye) enzyme. This inhibition was observed both in liquid culture and in a novel colorimetric assay to quantify bacterioruberin abundance based on the colony color. Addition of retinal to convert BO to the bacteriorhodopsin complex resulted in a partial rescue of bacterioruberin production. To explore if this regulatory mechanism occurs in other organisms, we expressed a Lye homolog and an opsin from in cruxopsin-3 expression inhibited bacterioruberin synthesis catalyzed by Lye but had no effect when bacterioruberin synthesis was catalyzed by or Lye. Conversely, BO did not inhibit Lye activity. Together, our data suggest that opsin-mediated inhibition of Lye is potentially widespread and represents an elegant regulatory mechanism that allows organisms to efficiently utilize ion-pumping rhodopsins obtained through lateral gene transfer. Many enzymes are complexes of proteins and nonprotein organic molecules called cofactors. To ensure efficient formation of functional complexes, organisms must regulate the production of proteins and cofactors. To study this regulation, we used bacteriorhodopsin from the archaeon Bacteriorhodopsin consists of the bacterioopsin protein and a retinal cofactor. In this article, we further characterize a novel regulatory mechanism in which bacterioopsin promotes retinal production by inhibiting a reaction that consumes lycopene, a retinal precursor. By expressing genes in a different organism, , we demonstrated that bacterioopsin alone is sufficient for this inhibition. We also found that an opsin from has inhibitory activity, suggesting that this regulatory mechanism might be found in other organisms.
[Mh] Termos MeSH primário: Archaea/metabolismo
Bacteriorodopsinas/metabolismo
Carotenoides/biossíntese
Haloferax volcanii/metabolismo
[Mh] Termos MeSH secundário: Bacteriorodopsinas/genética
Clonagem Molecular
Colorimetria
Expressão Gênica
Haloarcula/enzimologia
Haloarcula/genética
Haloferax volcanii/genética
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Retinaldeído/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Recombinant Proteins); 32719-43-0 (bacterioruberin); 36-88-4 (Carotenoids); 53026-44-1 (Bacteriorhodopsins); 54577-62-7 (bacterio-opsin); RR725D715M (Retinaldehyde)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171009
[Lr] Data última revisão:
171009
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170809
[St] Status:MEDLINE


  4 / 2139 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28780307
[Au] Autor:Wang K; Zhu X; Zhang K; Zhou F; Zhu L
[Ad] Endereço:Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi 214063, Jiangsu Province, China. Electronic address: wangke@jsinm.org.
[Ti] Título:Neuroprotective effect of tetramethylpyrazine against all-trans-retinal toxicity in the differentiated Y-79 cells via upregulation of IRBP expression.
[So] Source:Exp Cell Res;359(1):120-128, 2017 Oct 01.
[Is] ISSN:1090-2422
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:It is estimated that abnormal accumulation of all-trans-retinal (atRAL) is a leading cause of photoreceptor degeneration in retinal degenerative diseases. Deficiency of interphotoreceptor retinoid-binding protein (IRBP), a retinoid transporter in the visual cycle, is responsible for the impaired clearance of atRAL and results in atRAL toxicity in retina. Therefore, IRBP has been proposed to be a potent target in preventing atRAL-induced photoreceptor degeneration. In this study, the neuroprotective effect of tetramethylpyrazine (TMP) against atRAL toxicity in the differentiated Y-79 cells, a in vitro model of photoreceptor, was first investigated. Our findings showed that atRAL could induce cytotoxicity, oxidative/nitrosative stresses, apoptosis and leukostasis in the differentiated Y-79 cells; however, the pre-treatment of TMP significantly attenuated such effects in a dose-dependent manner. Furthermore, our results indicated that TMP exerted its neuroprotective effect mainly through upregulating IRBP expression. The present study significantly contributes to better understanding the important role of IRBP in retinal degenerative diseases and forms the basis of the therapeutic development of TMP in such diseases in the future.
[Mh] Termos MeSH primário: Diferenciação Celular/efeitos dos fármacos
Proteínas do Olho/metabolismo
Fármacos Neuroprotetores/farmacologia
Pirazinas/farmacologia
Retinaldeído/toxicidade
Proteínas de Ligação ao Retinol/metabolismo
Regulação para Cima/efeitos dos fármacos
[Mh] Termos MeSH secundário: Apoptose/efeitos dos fármacos
Morte Celular/efeitos dos fármacos
Linhagem Celular Tumoral
Seres Humanos
Molécula 1 de Adesão Intercelular/metabolismo
Leucostasia/patologia
Mitocôndrias/efeitos dos fármacos
Mitocôndrias/metabolismo
Neurônios/efeitos dos fármacos
Neurônios/metabolismo
Neurônios/patologia
Neuroproteção/efeitos dos fármacos
Nitrosação
Estresse Oxidativo/efeitos dos fármacos
Molécula 1 de Adesão de Célula Vascular/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Eye Proteins); 0 (Neuroprotective Agents); 0 (Pyrazines); 0 (Retinol-Binding Proteins); 0 (Vascular Cell Adhesion Molecule-1); 0 (interstitial retinol-binding protein); 126547-89-5 (Intercellular Adhesion Molecule-1); RR725D715M (Retinaldehyde); V80F4IA5XG (tetramethylpyrazine)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171016
[Lr] Data última revisão:
171016
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170807
[St] Status:MEDLINE


  5 / 2139 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28734946
[Au] Autor:Malechka VV; Moiseyev G; Takahashi Y; Shin Y; Ma JX
[Ad] Endereço:Department of Physiology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
[Ti] Título:Impaired Rhodopsin Generation in the Rat Model of Diabetic Retinopathy.
[So] Source:Am J Pathol;187(10):2222-2231, 2017 Oct.
[Is] ISSN:1525-2191
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Diabetic retinopathy is a common complication of diabetes mellitus. Diabetic patients experience functional deficits in dark adaptation, contrast sensitivity, and color perception before microvascular pathologies become apparent. Herein, we evaluated early changes in neural retinal function and in retinoid metabolism in the eye in diabetes. Streptozotocin-induced diabetic rats showed decreased a- and b-wave amplitudes of scotopic and photopic electroretinography responses 4 months after diabetes induction compared to nondiabetic controls. Although Western blot analysis revealed no difference in opsin expression, rhodopsin content was decreased in diabetic retinas, as shown by a difference in absorbance. Consistently, levels of 11-cis-retinal, the chromophore for visual pigments, were significantly lower in diabetic retinas compared to those in controls, suggesting a retinoid deficiency. Among visual cycle proteins, interphotoreceptor retinoid-binding protein and stimulated by retinoic acid 6 protein showed significantly lower levels in diabetic rats than those in nondiabetic controls. Similarly, serum levels of retinol-binding protein 4 and retinoids were significantly lower in diabetic rats. Overall, these results suggest that retinoid metabolism in the eye is impaired in type 1 diabetes, which leads to deficient generation of visual pigments and neural retinal dysfunction in early diabetes.
[Mh] Termos MeSH primário: Retinopatia Diabética/metabolismo
Retinopatia Diabética/patologia
Rodopsina/metabolismo
[Mh] Termos MeSH secundário: Animais
Diabetes Mellitus Experimental/sangue
Diabetes Mellitus Experimental/complicações
Diabetes Mellitus Experimental/metabolismo
Diabetes Mellitus Experimental/patologia
Retinopatia Diabética/sangue
Retinopatia Diabética/complicações
Modelos Animais de Doenças
Masculino
Células Fotorreceptoras de Vertebrados/metabolismo
Células Fotorreceptoras de Vertebrados/patologia
Ratos Wistar
Retina/patologia
Retina/fisiopatologia
Retinaldeído/metabolismo
Proteínas Plasmáticas de Ligação ao Retinol/metabolismo
Vias Visuais/metabolismo
Vias Visuais/patologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Rbp4 protein, rat); 0 (Retinol-Binding Proteins, Plasma); 9009-81-8 (Rhodopsin); RR725D715M (Retinaldehyde)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171004
[Lr] Data última revisão:
171004
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:170724
[St] Status:MEDLINE


  6 / 2139 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28732066
[Au] Autor:Gong X; Marisiddaiah R; Rubin LP
[Ad] Endereço:Department of Pediatrics, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America.
[Ti] Título:Inhibition of pulmonary ß-carotene 15, 15'-oxygenase expression by glucocorticoid involves PPARα.
[So] Source:PLoS One;12(7):e0181466, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:ß-carotene 15,15'-oxygenase (BCO1) catalyzes the first step in the conversion of dietary provitamin A carotenoids to vitamin A. This enzyme is expressed in a variety of developing and adult tissues, suggesting that its activity may regulate local retinoid synthesis. Vitamin A and related compounds (retinoids) are critical regulators of lung epithelial development, integrity, and injury repair. A balance between the actions of retinoids and glucocorticoids (GCs) promotes normal lung development and, in particular, alveolarization. Alterations in this balance, including vitamin A deficiency and GC excess, contribute to the development of chronic lung disorders. Consequently, we investigated if GCs counteract retinoid effects in alveolar epithelial cells by mechanisms involving BCO1-dependent local vitamin A metabolism. We demonstrate that BCO1 is expressed in human fetal lung tissue and human alveolar epithelial-like A549 cells. Our results indicate A549 cells metabolize ß-carotene to retinal and retinoic acid (RA). GCs exposure using dexamethasone (DEX) decreases BCO1 mRNA and protein levels in A549 cells and reduces BCO1 promoter activity via inhibiting peroxisome proliferator-activated receptor γ (PPARγ) DNA binding. DEX also induces expression of PPARα, which in turn most likely causes a decrease in PPARγ/RXRα heterodimer binding to the bco1 gene promoter and consequent inhibition of bco1 gene expression. PPARα knockdown with siRNA abolishes DEX-induced suppression of BCO1 expression, confirming the requirement for PPARα in this DEX-mediated BCO1 mechanism. Taken together, these findings provide the first evidence that GCs regulate vitamin A (retinoid) signaling via inhibition of bco1 gene expression in a PPARα-dependent manner. These results explicate novel aspects of local GC:retinoid interactions that may contribute to alveolar tissue remodeling in chronic lung diseases that affect children and, possibly, adults.
[Mh] Termos MeSH primário: Glucocorticoides/metabolismo
Pulmão/metabolismo
PPAR alfa/metabolismo
beta-Caroteno 15,15´-Mono-Oxigenase/metabolismo
[Mh] Termos MeSH secundário: Western Blotting
Linhagem Celular Tumoral
Cromatografia Líquida de Alta Pressão
Dexametasona/farmacologia
Ensaio de Desvio de Mobilidade Eletroforética
Regulação da Expressão Gênica/efeitos dos fármacos
Regulação da Expressão Gênica/fisiologia
Glucocorticoides/farmacologia
Seres Humanos
Pulmão/embriologia
PPAR alfa/genética
PPAR gama/metabolismo
Reação em Cadeia da Polimerase
Regiões Promotoras Genéticas
Interferência de RNA
RNA Mensageiro/metabolismo
Mucosa Respiratória/metabolismo
Retinaldeído/metabolismo
Tretinoína/metabolismo
beta-Caroteno 15,15'-Mono-Oxigenase/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Glucocorticoids); 0 (PPAR alpha); 0 (PPAR gamma); 0 (RNA, Messenger); 5688UTC01R (Tretinoin); 7S5I7G3JQL (Dexamethasone); EC 1.13.11.63 (BCO1 protein, human); EC 1.14.99.36 (beta-Carotene 15,15'-Monooxygenase); RR725D715M (Retinaldehyde)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171002
[Lr] Data última revisão:
171002
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170722
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0181466


  7 / 2139 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28700926
[Au] Autor:Tian H; Sakmar TP; Huber T
[Ad] Endereço:Laboratory of Chemical Biology and Signal Transduction, The Rockefeller University, New York, New York.
[Ti] Título:The Energetics of Chromophore Binding in the Visual Photoreceptor Rhodopsin.
[So] Source:Biophys J;113(1):60-72, 2017 Jul 11.
[Is] ISSN:1542-0086
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The visual photoreceptor rhodopsin is a prototypical G-protein-coupled receptor (GPCR) that stabilizes its inverse agonist ligand, 11-cis-retinal (11CR), by a covalent, protonated Schiff base linkage. In the visual dark adaptation, the fundamental molecular event after photobleaching of rhodopsin is the recombination reaction between its apoprotein opsin and 11CR. Here we present a detailed analysis of the kinetics and thermodynamics of this reaction, also known as the "regeneration reaction". We compared the regeneration of purified rhodopsin reconstituted into phospholipid/detergent bicelles with rhodopsin reconstituted into detergent micelles. We found that the lipid bilayer of bicelles stabilized the chromophore-free opsin over the long timescale required for the regeneration experiments, and also facilitated the ligand reuptake binding reaction. We utilized genetic code expansion and site-specific bioorthogonal labeling of rhodopsin with Alexa488 to enable, to our knowledge, a novel fluorescence resonance energy transfer-based measurement of the binding kinetics between opsin and 11CR. Based on these results, we report a complete energy diagram for the regeneration reaction of rhodopsin. We show that the dissociation reaction of rhodopsin to 11CR and opsin has a 25-pM equilibrium dissociation constant, which corresponds to only 0.3 kcal/mol stabilization compared to the noncovalent, tightly bound antagonist-GPCR complex of iodopindolol and ß-adrenergic receptor. However, 11CR dissociates four orders-of-magnitude slower than iodopindolol, which corresponds to a 6-kcal/mol higher dissociation free energy barrier. We further used isothermal titration calorimetry to show that ligand binding in rhodopsin is enthalpy driven with -22 kcal/mol, which is 12 kcal/mol more stable than the antagonist-GPCR complex. Our data provide insights into the ligand-receptor binding reaction for rhodopsin in particular, and for GPCRs more broadly.
[Mh] Termos MeSH primário: Retinaldeído/metabolismo
Rodopsina/metabolismo
[Mh] Termos MeSH secundário: Animais
Calorimetria
Bovinos
Ácidos Cólicos/química
Difusão Dinâmica da Luz
Transferência Ressonante de Energia de Fluorescência
Hidrodinâmica
Cinética
Bicamadas Lipídicas/química
Micelas
Fosfatidilcolinas/química
Fotodegradação
Ligação Proteica
Estabilidade Proteica
Receptores Adrenérgicos beta/química
Receptores Adrenérgicos beta/metabolismo
Retinaldeído/química
Rodopsina/agonistas
Rodopsina/química
Termodinâmica
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cholic Acids); 0 (Lipid Bilayers); 0 (Micelles); 0 (Phosphatidylcholines); 0 (Receptors, Adrenergic, beta); 059QF0KO0R (Water); 9009-81-8 (Rhodopsin); QBP25342AG (3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate); RR725D715M (Retinaldehyde); TE895536Y5 (1-palmitoyl-2-oleoylphosphatidylcholine)
[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:170713
[St] Status:MEDLINE


  8 / 2139 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28623234
[Au] Autor:Tsukamoto H; Chen IS; Kubo Y; Furutani Y
[Ad] Endereço:From the Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, Okazaki 444-8585, Japan, tsukamoh@ims.ac.jp.
[Ti] Título:A ciliary opsin in the brain of a marine annelid zooplankton is ultraviolet-sensitive, and the sensitivity is tuned by a single amino acid residue.
[So] Source:J Biol Chem;292(31):12971-12980, 2017 Aug 04.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Ciliary opsins were classically thought to function only in vertebrates for vision, but they have also been identified recently in invertebrates for non-visual photoreception. Larvae of the annelid are used as a zooplankton model, and this zooplankton species possesses a "vertebrate-type" ciliary opsin (named c-opsin) in the brain. c-opsin is suggested to relay light signals for melatonin production and circadian behaviors. Thus, the spectral and biochemical characteristics of this c-opsin would be directly related to non-visual photoreception in this zooplankton model. Here we demonstrate that the c-opsin can sense UV to activate intracellular signaling cascades and that it can directly bind exogenous all- -retinal. These results suggest that this c-opsin regulates circadian signaling in a UV-dependent manner and that it does not require a supply of 11- -retinal for photoreception. Avoidance of damaging UV irradiation is a major cause of large-scale daily zooplankton movement, and the observed capability of the c-opsin to transmit UV signals and bind all- retinal is ideally suited for sensing UV radiation in the brain, which presumably lacks enzymes producing 11- -retinal. Mutagenesis analyses indicated that a unique amino acid residue (Lys-94) is responsible for c-opsin-mediated UV sensing in the brain. We therefore propose that acquisition of the lysine residue in the c-opsin would be a critical event in the evolution of to enable detection of ambient UV light. In summary, our findings indicate that the c-opsin possesses spectral and biochemical properties suitable for UV sensing by the zooplankton model.
[Mh] Termos MeSH primário: Proteínas do Tecido Nervoso/metabolismo
Opsinas/metabolismo
Células Fotorreceptoras de Invertebrados/efeitos da radiação
Poliquetos/fisiologia
Sistemas do Segundo Mensageiro/efeitos da radiação
Zooplâncton/fisiologia
[Mh] Termos MeSH secundário: Substituição de Aminoácidos
Animais
Células COS
Cercopithecus aethiops
Cílios/metabolismo
Cílios/efeitos da radiação
Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/genética
Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/metabolismo
Lisina/química
Mutação
Proteínas do Tecido Nervoso/química
Proteínas do Tecido Nervoso/genética
Oócitos/metabolismo
Oócitos/efeitos da radiação
Opsinas/química
Opsinas/genética
Técnicas de Patch-Clamp
Células Fotorreceptoras de Invertebrados/metabolismo
Filogenia
Poliquetos/efeitos da radiação
Estabilidade Proteica/efeitos da radiação
Proteínas Recombinantes de Fusão/química
Proteínas Recombinantes de Fusão/metabolismo
Retinaldeído/química
Retinaldeído/metabolismo
Estereoisomerismo
Raios Ultravioleta
Xenopus
Zooplâncton/efeitos da radiação
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (G Protein-Coupled Inwardly-Rectifying Potassium Channels); 0 (Nerve Tissue Proteins); 0 (Opsins); 0 (Recombinant Fusion Proteins); K3Z4F929H6 (Lysine); RR725D715M (Retinaldehyde)
[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:170618
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M117.793539


  9 / 2139 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28493967
[Au] Autor:Tomobe K; Yamamoto E; Kholmurodov K; Yasuoka K
[Ad] Endereço:Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
[Ti] Título:Water permeation through the internal water pathway in activated GPCR rhodopsin.
[So] Source:PLoS One;12(5):e0176876, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Rhodopsin is a light-driven G-protein-coupled receptor that mediates signal transduction in eyes. Internal water molecules mediate activation of the receptor in a rhodopsin cascade reaction and contribute to conformational stability of the receptor. However, it remains unclear how internal water molecules exchange between the bulk and protein inside, in particular through a putative solvent pore on the cytoplasmic. Using all-atom molecular dynamics simulations, we identified the solvent pore on cytoplasmic side in both the Meta II state and the Opsin. On the other hand, the solvent pore does not exist in the dark-adapted rhodopsin. We revealed two characteristic narrow regions located within the solvent pore in the Meta II state. The narrow regions distinguish bulk and the internal hydration sites, one of which is adjacent to the conserved structural motif "NPxxY". Water molecules in the solvent pore diffuse by pushing or sometimes jumping a preceding water molecule due to the geometry of the solvent pore. These findings revealed a total water flux between the bulk and the protein inside in the Meta II state, and suggested that these pathways provide water molecules to the crucial sites of the activated rhodopsin.
[Mh] Termos MeSH primário: Rodopsina/química
Água/química
[Mh] Termos MeSH secundário: Animais
Sítios de Ligação
Bovinos
Cristalografia por Raios X
Permeabilidade
Estrutura Secundária de Proteína
Retinaldeído/metabolismo
Solventes/química
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Solvents); 059QF0KO0R (Water); 9009-81-8 (Rhodopsin); RR725D715M (Retinaldehyde)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170911
[Lr] Data última revisão:
170911
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170512
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0176876


  10 / 2139 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28487362
[Au] Autor:Alexander NS; Katayama K; Sun W; Salom D; Gulati S; Zhang J; Mogi M; Palczewski K; Jastrzebska B
[Ad] Endereço:From the Department of Pharmacology, School of Medicine and.
[Ti] Título:Complex binding pathways determine the regeneration of mammalian green cone opsin with a locked retinal analogue.
[So] Source:J Biol Chem;292(26):10983-10997, 2017 Jun 30.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Phototransduction is initiated when the absorption of light converts the 11- -retinal chromophore to its all- configuration in both rod and cone vertebrate photoreceptors. To sustain vision, 11- -retinal is continuously regenerated from its all- conformation through a series of enzymatic steps comprising the "visual or retinoid" cycle. Abnormalities in this cycle can compromise vision because of the diminished supply of 11- -retinal and the accumulation of toxic, constitutively active opsin. As shown previously for rod cells, attenuation of constitutively active opsin can be achieved with the unbleachable analogue, 11- -6-membered ring (11- -6mr)-retinal, which has therapeutic effects against certain degenerative retinal diseases. However, to discern the molecular mechanisms responsible for this action, pigment regeneration with this locked retinal analogue requires delineation also in cone cells. Here, we compared the regenerative properties of rod and green cone opsins with 11- -6mr-retinal and demonstrated that this retinal analogue could regenerate rod pigment but not green cone pigment. Based on structural modeling suggesting that Pro-205 in green cone opsin could prevent entry and binding of 11- -6mr-retinal, we initially mutated this residue to Ile, the corresponding residue in rhodopsin. However, this substitution did not enable green cone opsin to regenerate with 11- -6mr-retinal. Interestingly, deletion of 16 N-terminal amino acids in green cone opsin partially restored the binding of 11- -6mr-retinal. These results and our structural modeling indicate that a more complex binding pathway determines the regeneration of mammalian green cone opsin with chromophore analogues such as 11- -6mr-retinal.
[Mh] Termos MeSH primário: Modelos Moleculares
Opsinas/química
Retinaldeído/química
[Mh] Termos MeSH secundário: Animais
Seres Humanos
Opsinas/genética
Opsinas/metabolismo
Retinaldeído/genética
Retinaldeído/metabolismo
Células Sf9
Spodoptera
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Opsins); RR725D715M (Retinaldehyde)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170715
[Lr] Data última revisão:
170715
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170511
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M117.780478



página 1 de 214 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