HsdR subunit of the type I restriction-modification enzyme EcoR124I: biophysical characterisation and structural modelling.

ABSTRACT: Type I restriction-modification (RM) systems are large, multifunctional enzymes composed of three different subunits. HsdS and HsdM form a complex in which HsdS recognizes the target DNA sequence, and HsdM carries out methylation of adenosine residues. The HsdR subunit, when associated with the HsdS-HsdM complex, translocates DNA in an ATP-dependent process and cleaves unmethylated DNA at a distance of several thousand base-pairs from the recognition site. The molecular mechanism by which these enzymes translocate the DNA is not fully understood, in part because of the absence of crystal structures. To date, crystal structures have been determined for the individual HsdS and HsdM subunits and models have been built for the HsdM-HsdS complex with the DNA. However, no structure is available

SUBMITTER: Obarska-Kosinska A 

PROVIDER: S-EPMC2878639 | biostudies-literature | 2008 Feb

REPOSITORIES: biostudies-literature