Light-dependent gene regulation by a coenzyme B12-based photoreceptor.

ABSTRACT: Cobalamin (B(12)) typically functions as an enzyme cofactor but can also regulate gene expression via RNA-based riboswitches. B(12)-directed gene regulatory mechanisms via protein factors have, however, remained elusive. Recently, we reported down-regulation of a light-inducible promoter in the bacterium Myxococcus xanthus by two paralogous transcriptional repressors, of which one, CarH, but not the other, CarA, absolutely requires B(12) for activity even though both have a canonical B(12)-binding motif. Unanswered were what underlies this striking difference, what is the specific cobalamin used, and how it acts. Here, we show that coenzyme B(12) (5'-deoxyadenosylcobalamin, AdoB(12)), specifically dictates CarH function in the dark and on exposure to light. In the dark, AdoB(12)-binding to

SUBMITTER: Ortiz-Guerrero JM 

PROVIDER: S-EPMC3088613 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature