Dynamic DNA Helicase-DNA Polymerase Interactions Assure Processive Replication Fork Movement

Samir M. Hamdan, Donald E. Johnson, Nathan A. Tanner, Jong Bong Lee, Udi Qimron, Stanley Tabor, Antoine M. van Oijen, Charles C. Richardson

Research output: Contribution to journalArticlepeer-review

Abstract

A single copy of bacteriophage T7 DNA polymerase and DNA helicase advance the replication fork with a processivity greater than 17,000 nucleotides. Nonetheless, the polymerase transiently dissociates from the DNA without leaving the replisome. Ensemble and single-molecule techniques demonstrate that this dynamic processivity is made possible by two modes of DNA polymerase-helicase interaction. During DNA synthesis the polymerase and the helicase interact at a high-affinity site. In this polymerizing mode, the polymerase dissociates from the DNA approximately every 5000 bases. The polymerase, however, remains bound to the helicase via an electrostatic binding mode that involves the acidic C-terminal tail of the helicase and a basic region in the polymerase to which the processivity factor also binds. The polymerase transfers via the electrostatic interaction around the hexameric helicase in search of the primer-template.

Original languageEnglish
Pages (from-to)539-549
Number of pages11
JournalMolecular Cell
Volume27
Issue number4
DOIs
StatePublished - 17 Aug 2007
Externally publishedYes

Keywords

  • DNA

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