Identification of conserved amino acid residues of the Salmonella sigmaS chaperone Crl involved in Crl-sigmaS interactions.

ABSTRACT: Proteins that bind sigma factors typically attenuate the function of the sigma factor by restricting its access to the RNA polymerase (RNAP) core enzyme. An exception to this general rule is the Crl protein that binds the stationary-phase sigma factor sigma(S) (RpoS) and enhances its affinity for the RNAP core enzyme, thereby increasing expression of sigma(S)-dependent genes. Analyses of sequenced bacterial genomes revealed that crl is less widespread and less conserved at the sequence level than rpoS. Seventeen residues are conserved in all members of the Crl family. Site-directed mutagenesis of the crl gene from Salmonella enterica serovar Typhimurium and complementation of a Deltacrl mutant of Salmonella indicated that substitution of the conserved residues Y22, F53, W56, and W82 decrea

SUBMITTER: Monteil V 

PROVIDER: S-EPMC2812953 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature