Structural highlights
Function
[DPO3B_ECOLI] DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria. This DNA polymerase also exhibits 3' to 5' exonuclease activity. The beta chain is required for initiation of replication once it is clamped onto DNA, it slides freely (bidirectional and ATP-independent) along duplex DNA. [HOLA_ECOLI] DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria. This DNA polymerase also exhibits 3' to 5' exonuclease activity. The delta subunit seems to interact with the gamma subunit to transfer the beta subunit on the DNA.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The dimeric ring-shaped sliding clamp of E. coli DNA polymerase III (beta subunit, homolog of eukaryotic PCNA) is loaded onto DNA by the clamp loader gamma complex (homolog of eukaryotic Replication Factor C, RFC). The delta subunit of the gamma complex binds to the beta ring and opens it. The crystal structure of a beta:delta complex shows that delta, which is structurally related to the delta' and gamma subunits of the gamma complex, is a molecular wrench that induces or traps a conformational change in beta such that one of its dimer interfaces is destabilized. Structural comparisons and molecular dynamics simulations suggest a spring-loaded mechanism in which the beta ring opens spontaneously once a dimer interface is perturbed by the delta wrench.
Mechanism of processivity clamp opening by the delta subunit wrench of the clamp loader complex of E. coli DNA polymerase III.,Jeruzalmi D, Yurieva O, Zhao Y, Young M, Stewart J, Hingorani M, O'Donnell M, Kuriyan J Cell. 2001 Aug 24;106(4):417-28. PMID:11525728[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Jeruzalmi D, Yurieva O, Zhao Y, Young M, Stewart J, Hingorani M, O'Donnell M, Kuriyan J. Mechanism of processivity clamp opening by the delta subunit wrench of the clamp loader complex of E. coli DNA polymerase III. Cell. 2001 Aug 24;106(4):417-28. PMID:11525728
