RelB and RelE of Escherichia coli form a tight complex that represses transcription via the ribbon-helix-helix motif in RelB.

ABSTRACT: RelB, the ribbon-helix-helix (RHH) repressor encoded by the relBE toxin-antitoxin locus of Escherichia coli, interacts with RelE and thereby counteracts the mRNA cleavage activity of RelE. In addition, RelB dimers repress the strong relBE promoter and this repression by RelB is enhanced by RelE; that is, RelE functions as a transcriptional co-repressor. RelB is a Lon protease substrate, and Lon is required both for activation of relBE transcription and for activation of the mRNA cleavage activity of RelE. Here we characterize the molecular interactions important for transcriptional control of the relBE model operon. Using an in vivo screen for relB mutants, we identified multiple nucleotide changes that map to important amino acid positions within the DNA-binding domain formed by the N-ter

SUBMITTER: Overgaard M 

PROVIDER: S-EPMC2812701 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature