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Evidence for the role of Mycobacteriumtuberculosis RecG helicase in DNA repair and recombination

Thakur, Roshan S and Basavaraju, Shivakumar and Somyajit, Kumar and Jain, Akshatha and Subramanya, Shreelakshmi and Muniyappa, Kalappa and Nagaraju, Ganesh (2013) Evidence for the role of Mycobacteriumtuberculosis RecG helicase in DNA repair and recombination. In: FEBS Journal, 280 (8). pp. 1841-1860.

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Official URL: http://dx.doi.org/10.1111/febs.12208

Abstract

In order to survive and replicate in a variety of stressful conditions during its life cycle, Mycobacteriumtuberculosis must possess mechanisms to safeguard the integrity of the genome. Although DNA repair and recombination related genes are thought to play key roles in the repair of damaged DNA in all organisms, so far only a few of them have been functionally characterized in the tubercle bacillus. In this study, we show that M.tuberculosis RecG (MtRecG) expression was induced in response to different genotoxic agents. Strikingly, expression of MtRecG in Escherichiacoli recG mutant strain provided protection against mitomycin C, methyl methane sulfonate and UV induced cell death. Purified MtRecG exhibited higher binding affinity for the Holliday junction (HJ) compared with a number of canonical recombinational DNA repair intermediates. Notably, although MtRecG binds at the core of the mobile and immobile HJs, and with higher binding affinity for the immobile HJ, branch migration was evident only in the case of the mobile HJ. Furthermore, immobile HJs stimulate MtRecG ATPase activity less efficiently than mobile HJs. In addition to HJ substrates, MtRecG exhibited binding affinity for a variety of branched DNA structures including three-way junctions, replication forks, flap structures, forked duplex and a D-loop structure, but demonstrated strong unwinding activity on replication fork and flap DNA structures. Together, these results support that MtRecG plays an important role in processes related to DNA metabolism under normal as well as stress conditions.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to John Wiley and Sons.
Keywords: DNA Repair; Genome Stability; Helicase; Holliday Junction; Recombination
Department/Centre: Division of Biological Sciences > Biochemistry
Depositing User: Francis Jayakanth
Date Deposited: 28 May 2013 06:51
Last Modified: 28 May 2013 06:51
URI: http://eprints.iisc.ac.in/id/eprint/46577

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