RecX protein abrogates ATP hydrolysis and strand exchange promoted by RecA: Insights into negative regulation of homologous recombination

Venkatesh, R and Ganesh, N and Guhan, N and Reddy, Sreedhar M and Chandrasekhar, T and Muniyappa, K (2002) RecX protein abrogates ATP hydrolysis and strand exchange promoted by RecA: Insights into negative regulation of homologous recombination. In: Proceedings of the National Academy of Sciences of the United States of America, 99 (19). pp. 12091-12096.

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Abstract

In many eubacteria, coexpression of recX with recA is essential for attenuation of the deleterious effects of recA overexpression; however, the molecular mechanism has remained enigmatic. Here, we show that Mycobacterium tuberculosis RecX binds directly to M. tuberculosis RecA as well as M. smegmatis and E. coli RecA proteins in vivo and in vitro, but not single-stranded DNA binding protein. The direct association of RecX with RecA failed to regulate the specificity or extent of binding of RecA either to DNA or ATP, ligands that are central to activation of its functions. Significantly, RecX severely impeded ATP hydrolysis and the generation of heteroduplex DNA promoted by homologous, as well as heterologous, RecA proteins. These findings reveal a mode of negative regulation of RecA, and imply that RecX might act as an anti-recombinase to quell inappropriate recombinational repair during normal DNA metabolism.

Item Type:	Journal Article
Publication:	Proceedings of the National Academy of Sciences of the United States of America
Publisher:	National Academy of Sciences
Additional Information:	Copyright of this article belongs to National Academy of Sciences.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	24 Oct 2007
Last Modified:	19 Sep 2010 04:40
URI:	http://eprints.iisc.ac.in/id/eprint/12346

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