spacer Human topoisomerase iibeta in complex with DNA and ametantrone
Primary citation
Title On the structural basis and design guidelines for type II topoisomerase-targeting anticancer drugs
Authors Wu, C.C.search; Li, Y.C.search; Wang, Y.R.search; Li, T.K.search; Chan, N.L.search
Journal NUCLEIC ACIDS RES.search vol:41, pag:10630-10640 (2013), Identifiers: PubMed ID (24038465)search DOI (10.1093/nar/gkt828)
Abstract Type II topoisomerases (Top2s) alter DNA topology via the formation of an enzyme-DNA adduct termed cleavage complex, which harbors a transient double-strand break in one DNA to allow the passage of another. Agents targeting human Top2s are clinically active anticancer drugs whose trapping of Top2-mediated DNA breakage effectively induces genome fragmentation and cell death. To understand the structural basis of this drug action, we previously determined the structure of human Top2 β-isoform forming a cleavage complex with the drug etoposide and DNA, and described the insertion of drug into DNA cleavage site and drug-induced decoupling of catalytic groups. By developing a post-crystallization drug replacement procedure that simplifies structural characterization of drug-stabilized cleavage complexes, we have extended the analysis toward other structurally distinct drugs, m-AMSA and mitoxantrone. Besides the expected drug intercalation, a switch in ribose puckering in the 3'-nucleotide of the cleavage site was robustly observed in the new structures, representing a new mechanism for trapping the Top2 cleavage complex. Analysis of drug-binding modes and the conformational landscapes of the drug-binding pockets provide rationalization of the drugs' structural-activity relationships and explain why Top2 mutants exhibit differential effects toward each drug. Drug design guidelines were proposed to facilitate the development of isoform-specific Top2-targeting anticancer agents.
MeSH terms
Other entries described in this publication 4g0v, 4j3n, 4g0u
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