3LFP: Crystal Structure Of The Restriction-Modification Controller Protein C.Csp231i

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 analysis 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.
PDB ID: 3LFPDownload
MMDB ID: 88335
PDB Deposition Date: 2010/1/18
Updated in MMDB: 2011/10
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 3LFP: dimeric; determined by author and by software (PISA)
Molecular Components in 3LFP
Label Count Molecule
Proteins (2 molecules)
Csp231i C Protein
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB