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Force and ATP hydrolysis dependent regulation of RecA nucleoprotein filament by single-stranded DNA binding protein

Fu, Hongxia and Le, Shimin and Chen, Hu and Muniyappa, K and Yan, Jie (2013) Force and ATP hydrolysis dependent regulation of RecA nucleoprotein filament by single-stranded DNA binding protein. In: NUCLEIC ACIDS RESEARCH, 41 (2). pp. 924-932.

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Official URL: http://dx.doi.org/10.1093/nar/gks1162

Abstract

In Escherichia coli, the filament of RecA formed on single-stranded DNA (ssDNA) is essential for recombinational DNA repair. Although ssDNA-binding protein (SSB) plays a complicated role in RecA reactions in vivo, much of our understanding of the mechanism is based on RecA binding directly to ssDNA. Here we investigate the role of SSB in the regulation of RecA polymerization on ssDNA, based on the differential force responses of a single 576-nucleotide-long ssDNA associated with RecA and SSB. We find that SSB outcompetes higher concentrations of RecA, resulting in inhibition of RecA nucleation. In addition, we find that pre-formed RecA filaments de-polymerize at low force in an ATP hydrolysis- and SSB-dependent manner. At higher forces, re-polymerization takes place, which displaces SSB from ssDNA. These findings provide a physical picture of the competition between RecA and SSB under tension on the scale of the entire nucleoprotein SSB array, which have broad biological implications particularly with regard to competitive molecular binding.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to OXFORD UNIV PRESS, ENGLAND
Department/Centre: Division of Biological Sciences > Biochemistry
Depositing User: Francis Jayakanth
Date Deposited: 05 Mar 2013 06:15
Last Modified: 05 Mar 2013 06:15
URI: http://eprints.iisc.ac.in/id/eprint/45961

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