Evolutionary clues to DNA polymerase III beta clamp structural mechanisms.

ABSTRACT: The prokaryotic DNA polymerase III beta homodimeric clamp links the replication complex to DNA during polynucleotide synthesis. This clamp is loaded onto DNA and unloaded by the clamp loader complex, the delta subunit of which by itself can bind to and open the clamp. beta Clamps from diverse bacteria were examined using contrast hierarchical alignment and interaction network (CHAIN) analysis, a statistical approach that categorizes and measures the evolutionary constraints imposed on protein sequences by natural selection. Some constraints are subtle inasmuch as they are unique to certain bacteria. Examination of corresponding molecular interactions within structures of the Escherichia coli beta dimeric and delta-beta complexes reveals that N320, Y323 and R176, which are subject to very s

SUBMITTER: Neuwald AF 

PROVIDER: S-EPMC169876 | biostudies-literature | 2003 Aug

REPOSITORIES: biostudies-literature