5gwk

Human topoisomerase IIalpha in complex with DNA and etoposide

spinqualitylabelsall models 5gwk, resolution 3.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5gwk is a 6 chain structure with sequence from Homo sapiens and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.152Å Ligands: EVP, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TOP2A_HUMAN Control of topological states of DNA by transient breakage and subsequent rejoining of DNA strands. Topoisomerase II makes double-strand breaks. Essential during mitosis and meiosis for proper segregation of daughter chromosomes. Publication Abstract from PubMed Human type II topoisomerase (Top2) isoforms, hTop2alpha and hTop2beta, 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 hTop2alpha and hTop2beta 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-N2beta, by replacing the methionine-juxtaposing group of the drug etoposide with a cis-dichlorodiammineplatinum(II) moiety. Compared to etoposide, etoplatin-N2beta more potently inhibits both human Top2s. While the DNA breaks arrested by etoposide can be rejoined, those captured by etoplatin-N2beta are practically irreversible. Crystallographic analyses of hTop2beta complexed with DNA and etoplatin-N2beta 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. Producing irreversible topoisomerase II-mediated DNA breaks by site-specific Pt(II)-methionine coordination chemistry.,Wang YR, Chen SF, Wu CC, Liao YW, Lin TS, Liu KT, Chen YS, Li TK, Chien TC, Chan NL Nucleic Acids Res. 2017 Oct 13;45(18):10861-10871. doi: 10.1093/nar/gkx742. PMID:28977631 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Topoisomerase 3D structures

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