Contributions of the individual hydrophobic clefts of the Escherichia coli beta sliding clamp to clamp loading, DNA replication and clamp recycling.

ABSTRACT: The homodimeric Escherichia coli beta sliding clamp contains two hydrophobic clefts with which proteins involved in DNA replication, repair and damage tolerance interact. Deletion of the C-terminal five residues of beta (beta(C)) disrupted both clefts, severely impairing interactions of the clamp with the DnaX clamp loader, as well as the replicative DNA polymerase, Pol III. In order to determine whether both clefts were required for loading clamp onto DNA, stimulation of Pol III replication and removal of clamp from DNA after replication was complete, we developed a method for purification of heterodimeric clamp proteins comprised of one wild-type subunit (beta(+)), and one beta(C) subunit (beta(+)/beta(C)). The beta(+)/beta(C) heterodimer interacted normally with the DnaX clamp loader, a

SUBMITTER: Scouten Ponticelli SK 

PROVIDER: S-EPMC2685083 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature