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Functional Analysis of DNA Replication Fork Reversal Catalyzed by Mycobacterium tuberculosis RuvAB Proteins

Khanduja, Jasbeer S and Muniyappa, K (2012) Functional Analysis of DNA Replication Fork Reversal Catalyzed by Mycobacterium tuberculosis RuvAB Proteins. In: Journal of Biological Chemistry, 287 (2). pp. 1345-1360.

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Official URL: http://www.jbc.org/content/287/2/1345

Abstract

Initially discovered in Escherichia coli, RuvAB proteins are ubiquitous in bacteria and play a dual role as molecular motor proteins responsible for branch migration of the Holliday junction(s) and reversal of stalled replication forks. Despite mounting genetic evidence for a crucial role of RuvA and RuvB proteins in reversal of stalled replication forks, the mechanistic aspects of this process are still not fully understood. Here, we elucidate the ability of Mycobacterium tuberculosis RuvAB (MtRuvAB) complex to catalyze the reversal of replication forks using a range of DNA replication fork substrates. Our studies show that MtRuvAB, unlike E. coli RuvAB, is able to drive replication fork reversal via the formation of Holliday junction intermediates, suggesting that RuvAB-catalyzed fork reversal involves concerted unwinding and annealing of nascent leading and lagging strands. We also demonstrate the reversal of replication forks carrying hemi-replicated DNA, indicating that MtRuvAB complex-catalyzed fork reversal is independent of symmetry at the fork junction. The fork reversal reaction catalyzed by MtRuvAB is coupled to ATP hydrolysis, is processive, and culminates in the formation of an extended reverse DNA arm. Notably, we found that sequence heterology failed to impede the fork reversal activity of MtRuvAB. We discuss the implications of these results in the context of recognition and processing of varied types of replication fork structures by RuvAB proteins.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to The American Society for Biochemistry and Molecular Biology.
Department/Centre: Division of Biological Sciences > Biochemistry
Date Deposited: 15 Feb 2012 05:04
Last Modified: 15 Feb 2012 05:04
URI: http://eprints.iisc.ernet.in/id/eprint/43433

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