3lis

Publication Abstract from PubMed

Controller proteins play a key role in the temporal regulation of gene expression in bacterial restriction-modification (R-M) systems and are important mediators of horizontal gene transfer. They form the basis of a highly cooperative, concentration-dependent genetic switch involved in both activation and repression of R-M genes. Here we present biophysical, biochemical, and high-resolution structural analyses of a novel class of controller proteins, exemplified by C.Csp231I. In contrast to all previously solved C-protein structures, each protein subunit has two extra helices at the C-terminus, which play a large part in maintaining the dimer interface. The DNA binding site of the protein is also novel, having largely AAAA tracts between the palindromic recognition half-sites, suggesting tight bending of the DNA. The protein structure shows an unusual positively charged surface that could form the basis for wrapping the DNA completely around the C-protein dimer.

Structural Analysis of a Novel Class of R-M Controller Proteins: C.Csp231I from Citrobacter sp. RFL231.,McGeehan JE, Streeter SD, Thresh SJ, Taylor JE, Shevtsov MB, Kneale GG J Mol Biol. 2011 Mar 31. PMID:21440553^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.