1kb1

From Proteopedia

Revision as of 22:56, 24 November 2007

SOLUTION STRUCTURE OF AN 11-MER DNA DUPLEX CONTAINING 6-THIOGUANINE OPPOSITE CYTOSINE

Overview

The incorporation of 6-thioguanine (S6G) into DNA is an essential step in, the cytotoxic activity of thiopurines. However, the structural effects of, this substitution on duplex DNA have not been fully characterized. Here, we present the solution structures of DNA duplexes containing S6G opposite, thymine (S6G.T) and opposite cytosine (S6G.C), solved by high-resolution, NMR spectroscopy and restrained molecular dynamics. The data indicate that, both duplexes adopt right-handed helical conformations with all, Watson-Crick hydrogen bonding in place. The S6G.T structures exhibit a, wobble-type base pairing at the lesion site, with thymine shifted toward, the major groove and S6G displaced toward the minor groove. Aside from the, lesion site, the helices, including the flanking base pairs, are not, highly perturbed by the presence of the lesion. Surprisingly, thermal, dependence experiments suggest greater stability in the S6G-T mismatch, than the S6G-C base pair.

About this Structure

1KB1 is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.

Reference

Structural effect of the anticancer agent 6-thioguanine on duplex DNA., Bohon J, de los Santos CR, Nucleic Acids Res. 2003 Feb 15;31(4):1331-8. PMID:12582253

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