Download MendeleyThe mechanism of topoisomerase I poisoning by a camptothecin analog
Staker, B.L., Hjerrild, K., Feese, M.D., Behnke, C.A., Burgin Jr., A.B., Stewart, L.J.(2002) Proc Natl Acad Sci U S A 99: 15387-15392
- PubMed: 12426403
- DOI: https://doi.org/10.1073/pnas.242259599
- Primary Citation of Related Structures:
1K4S, 1K4T - PubMed Abstract:
We report the x-ray crystal structure of human topoisomerase I covalently joined to double-stranded DNA and bound to the clinically approved anticancer agent Topotecan. Topotecan mimics a DNA base pair and binds at the site of DNA cleavage by intercalating between the upstream (-1) and downstream (+1) base pairs. Intercalation displaces the downstream DNA, thus preventing religation of the cleaved strand. By specifically binding to the enzyme-substrate complex, Topotecan acts as an uncompetitive inhibitor. The structure can explain several of the known structure-activity relationships of the camptothecin family of anticancer drugs and suggests that there are at least two classes of mutations that can produce a drug-resistant enzyme. The first class includes changes to residues that contribute to direct interactions with the drug, whereas a second class would alter interactions with the DNA and thereby destabilize the drug-binding site.
Organizational Affiliation:
deCODE genetics, Incorporated, BioStructures Group, 7869 Northeast Day Road West, Bainbridge Island, WA 98110, USA.
