Sequence specific interaction of Mycobacterium smegmatis topoisomerase I with duplex DNA

Bhaduri, Tisha ; Sikder, Devanjan ; Nagaraja, Valakunja (1998) Sequence specific interaction of Mycobacterium smegmatis topoisomerase I with duplex DNA Nucleic Acids Research, 26 (7). pp. 1668-1674. ISSN 0305-1048

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Official URL: http://nar.oxfordjournals.org/content/26/7/1668.sh...

Related URL: http://dx.doi.org/10.1093/nar/26.7.1668

Abstract

We have identified strong topoisomerase sites (STS) for Mycobacteruim smegmatis topoisomerase I in double-stranded DNA context using electrophoretic mobility shift assay of enzyme-DNA covalent complexes. Mg2+, an essential component for DNA relaxation activity of the enzyme, is not required for binding to DNA. The enzyme makes single-stranded nicks, with transient covalent interaction at the 5'-end of the broken DNA strand, a characteristic akin to prokaryotic topoisomerases. More importantly, the enzyme binds to duplex DNA having a preferred site with high affinity, a property similar to the eukaryotic type I topoisomerases. The preferred cleavage site is mapped on a 65 bp duplex DNA and found to be CG/TCTT. Thus, the enzyme resembles other prokaryotic type I topoisomerases in mechanistics of the reaction, but is similar to eukaryotic enzymes in DNA recognition properties.

Item Type:Article
Source:Copyright of this article belongs to Oxford University Press.
ID Code:26923
Deposited On:08 Dec 2010 12:59
Last Modified:17 May 2016 10:12

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