Inhibition of Mycobacterium smegmatis topoisomerase I by specific oligonucleotides

Bhaduri, Tisha and Basak, Shashwati and Sikder, Devanjan and Nagaraja, Valakunja (2000) Inhibition of Mycobacterium smegmatis topoisomerase I by specific oligonucleotides. In: FEBS Letters, 486 (2). pp. 126-130.

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Abstract

DNA topoisomerase I from Mycobacterium smegmatis unlike many other type I topoisomerases is a site specific DNA binding protein. We have investigated the sequence specific DNA binding characteristics of the enzyme using specific oligonucleotides of varied length. DNA binding, oligonucleotide competition and covalent complex assays show that the substrate length requirement for interaction is much longer ($\sim 20$ nucleotides) in contrast to short length substrates (eight nucleotides) reported for Escherichia coli topoisomerase I and III. P1 nuclease and $KMnO_4$ footprinting experiments indicate a large protected region spanning about 20 nucleotides upstream and 2–3 nucleotides downstream of the cleavage site. Binding characteristics indicate that the enzyme interacts efficiently with both single-stranded and double-stranded substrates containing strong topoisomerase I sites (STS), a unique property not shared by any other type I topoisomerase. The oligonucleotides containing STS effectively inhibit the M. smegmatis topoisomerase I DNA relaxation activity.

Item Type:	Journal Article
Publication:	FEBS Letters
Publisher:	Federation of European Biochemical Societies
Additional Information:	Copyright of this article belongs to Federation of European Biochemical Societies.
Keywords:	DNA topoisomerase I;Mycobacterium;Oligodeoxynucleotide
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	17 Oct 2007
Last Modified:	19 Sep 2010 04:40
URI:	http://eprints.iisc.ac.in/id/eprint/12300

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