A New Facet of Vitamin B12: Gene Regulation by Cobalamin-Based Photoreceptors.
Annu Rev Biochem
; 86: 485-514, 2017 06 20.
Article
em En
| MEDLINE
| ID: mdl-28654327
ABSTRACT
Living organisms sense and respond to light, a crucial environmental factor, using photoreceptors, which rely on bound chromophores such as retinal, flavins, or linear tetrapyrroles for light sensing. The discovery of photoreceptors that sense light using 5'-deoxyadenosylcobalamin, a form of vitamin B12 that is best known as an enzyme cofactor, has expanded the number of known photoreceptor families and unveiled a new biological role of this vitamin. The prototype of these B12-dependent photoreceptors, the transcriptional repressor CarH, is widespread in bacteria and mediates light-dependent gene regulation in a photoprotective cellular response. CarH activity as a transcription factor relies on the modulation of its oligomeric state by 5'-deoxyadenosylcobalamin and light. This review surveys current knowledge about these B12-dependent photoreceptors, their distribution and mode of action, and the structural and photochemical basis of how they orchestrate signal transduction and control gene expression.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas Repressoras
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Proteínas de Bactérias
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Fatores de Transcrição
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Regulação Bacteriana da Expressão Gênica
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Cobamidas
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Fotorreceptores Microbianos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article