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 language | English (US) |
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Pages (from-to) | 539-549 |
Number of pages | 11 |
Journal | Molecular cell |
Volume | 27 |
Issue number | 4 |
DOIs | |
State | Published - Aug 17 2007 |
Externally published | Yes |
Bibliographical note
Funding Information:We thank Seung-Joo Lee for providing gp4-CΔ17 and Steven Moskowitz (Advanced Medical Graphics) for illustrations. This work was supported in part by United States Public Health Service Grant GM-54397 and by United States Department of Energy Grant DE-FG02-96ER62251. A.M.v.O. acknowledges funding from a National Science Foundation Career Award (MCB 0543784).
Keywords
- DNA
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology