Plasticity in oligomerization, operator architecture, and DNA binding in the mode of action of a bacterial B₁₂-based photoreceptor.

ABSTRACT: Newly discovered bacterial photoreceptors called CarH sense light by using 5'-deoxyadenosylcobalamin (AdoCbl). They repress their own expression and that of genes for carotenoid synthesis by binding in the dark to operator DNA as AdoCbl-bound tetramers, whose light-induced disassembly relieves repression. High-resolution structures of Thermus thermophilus CarH_Tt have provided snapshots of the dark and light states and have revealed a unique DNA-binding mode whereby only three of four DNA-binding domains contact an operator comprising three tandem direct repeats. To gain further insights into CarH photoreceptors and employing biochemical, spectroscopic, mutational, and computational analyses, here we investigated CarH_Bm from Bacillus megaterium We found t

SUBMITTER: Fernandez-Zapata J 

PROVIDER: S-EPMC6240859 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature