Download MendeleyProducing irreversible topoisomerase II-mediated DNA breaks by site-specific Pt(II)-methionine coordination chemistry
Wang, Y.R., Chen, S.F., Wu, C.C., Liao, Y.W., Lin, T.S., Liu, K.T., Chen, Y.S., Li, T.K., Chien, T.C., Chan, N.L.(2017) Nucleic Acids Res 45: 10861-10871
- PubMed: 28977631
- DOI: https://doi.org/10.1093/nar/gkx742
- Primary Citation of Related Structures:
5GWI, 5GWJ, 5GWK - PubMed Abstract:
Human type II topoisomerase (Top2) isoforms, hTop2α and hTop2β, are targeted by some of the most successful anticancer drugs. These drugs induce Top2-mediated DNA cleavage to trigger cell-death pathways. The potency of these drugs correlates positively with their efficacy in stabilizing the enzyme-mediated DNA breaks. Structural analysis of hTop2α and hTop2β revealed the presence of methionine residues in the drug-binding pocket, we therefore tested whether a tighter Top2-drug association may be accomplished by introducing a methionine-reactive Pt2+ into a drug to further stabilize the DNA break. Herein, we synthesized an organoplatinum compound, etoplatin-N2β, by replacing the methionine-juxtaposing group of the drug etoposide with a cis-dichlorodiammineplatinum(II) moiety. Compared to etoposide, etoplatin-N2β more potently inhibits both human Top2s. While the DNA breaks arrested by etoposide can be rejoined, those captured by etoplatin-N2β are practically irreversible. Crystallographic analyses of hTop2β complexed with DNA and etoplatin-N2β demonstrate coordinate bond formation between Pt2+ and a flanking methionine. Notably, this stable coordinate tether can be loosened by disrupting the structural integrity of drug-binding pocket, suggesting that Pt2+ coordination chemistry may allow for the development of potent inhibitors with protein conformation-dependent reversibility. This approach may be exploited to achieve isoform-specific targeting of human Top2s.
Organizational Affiliation:
Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 100, Taiwan.
