B-Ring-Aryl Substituted Luotonin A Analogues with a New Binding Mode to the Topoisomerase 1-DNA Complex Show Enhanced Cytotoxic Activity
Figure 6
Docking of luotonin A, topotecan and compound 3c.
A. A full view of the topoisomerase 1-DNA complex with luotonin A docked onto the active site. B. Expansion of the binding site. Luotonin A (navy blue) is shown compared with the position found for topotecan (brown) by crystallography, showing an excellent concordance between both poses. The base pairs are coloured in red (−1) and green (+1). The topoisomerase Arg364 residue responsible for hydrogen bonding with the compounds is displayed in blue. C. Docking of compound 3c, showing the hydrogen bonding interaction of Arg364 with both nitrogens N5 and N6.