Insights into the replisome from the structure of a ternary complex of the DNA polymerase III alpha-subunit

Richard A. Wing, Scott Bailey, Thomas A. Steitz

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

The crystal structure of the catalytic alpha-subunit of the DNA polymerase III (Pol IIIalpha) holoenzyme bound to primer-template DNA and an incoming deoxy-nucleoside 5'-triphosphate has been determined at 4.6-A resolution. The polymerase interacts with the sugar-phosphate backbone of the DNA across its minor groove, which is made possible by significant movements of the thumb, finger, and beta-binding domains relative to their orientations in the unliganded polymerase structure. Additionally, the DNA and incoming nucleotide are bound to the active site of Pol IIIalpha nearly identically as they are in their complex with DNA polymerase beta, thereby proving that the eubacterial replicating polymerase, but not the eukaryotic replicating polymerase, is homologous to DNA polymerase beta. Finally, superimposing a recent structure of the clamp bound to DNA on this Pol IIIalpha complex with DNA places a loop of the beta-binding domain into the appropriate clamp cleft and supports a mechanism of polymerase switching.

Original languageEnglish (US)
Title of host publicationStructural Insights into Gene Expression and Protein Synthesis
PublisherWorld Scientific Publishing Co.
Pages354-365
Number of pages12
ISBN (Electronic)9789811215865
ISBN (Print)9789811215858
StatePublished - Jan 1 2020
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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