Single-molecule studies of fork dynamics in Escherichia coli DNA replication

Tanner, Nathan A., Hamdan, Samir M., Jergic, Slobodan, Loscha, Karin V., Schaeffer, Patrick M., Dixon, Nicholas E., and van Oijen, Antoine M. (2008) Single-molecule studies of fork dynamics in Escherichia coli DNA replication. Nature Structural and Molecular Biology, 15 (2). pp. 170-176.

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View at Publisher Website: http://dx.doi.org/10.1038/nsmb0908-998a

Abstract

We present single-molecule studies of the Escherichia coli replication machinery. We visualize individual E. coli DNA polymerase III (Pol III) holoenzymes engaging in primer extension and leading-strand synthesis. When coupled to the replicative helicase DnaB, Pol III mediates leading-strand synthesis with a processivity of 10.5 kilobases (kb), eight-fold higher than that by Pol III alone. Addition of the primase DnaG causes a three-fold reduction in the processivity of leading-strand synthesis, an effect dependent upon the DnaB-DnaG protein-protein interaction rather than primase activity. A single-molecule analysis of the replication kinetics with varying DnaG concentrations indicates that a cooperative binding of two or three DnaG monomers to DnaB halts synthesis. Modulation of DnaB helicase activity through the interaction with DnaG suggests a mechanism that prevents leading-strand synthesis from outpacing lagging-strand synthesis during slow primer synthesis on the lagging strand.

Item ID: 5124
Item Type: Article (Refereed Research - C1)
Additional Information:

Publisher's note: "In the version of this article initially published, Karin V. Loscha was missing from the list of authors. The error has been corrected in the HTML and PDF versions of the article".

ISSN: 1545-9985
Date Deposited: 02 Sep 2009 00:03
FoR Codes: 06 BIOLOGICAL SCIENCES > 0699 Other Biological Sciences > 069999 Biological Sciences not elsewhere classified @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 100%
Citation Count from Web of Science Web of Science 50
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