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From Proteopedia
Crystal structure of human topoisomerase II beta in complex with DNA: a new quaternary conformation showing opening of the protein-linked DNA-gate
Structural highlights
Function[TOP2B_HUMAN] Control of topological states of DNA by transient breakage and subsequent rejoining of DNA strands. Topoisomerase II makes double-strand breaks. Indirectly involved in vitamin D-coupled transcription regulation via its association with the WINAC complex, a chromatin-remodeling complex recruited by vitamin D receptor (VDR), which is required for the ligand-bound VDR-mediated transrepression of the CYP27B1 gene.[1] [2] Publication Abstract from PubMedType IIA topoisomerases (Top2s) manipulate the handedness of DNA crossovers by introducing a transient and protein-linked double-strand break in one DNA duplex, termed the DNA-gate, whose opening allows another DNA segment to be transported through to change the DNA topology. Despite the central importance of this gate-opening event to Top2 function, the DNA-gate in all reported structures of Top2-DNA complexes is in the closed state. Here we present the crystal structure of a human Top2 DNA-gate in an open conformation, which not only reveals structural characteristics of its DNA-conducting path, but also uncovers unexpected yet functionally significant conformational changes associated with gate-opening. This structure further implicates Top2's preference for a left-handed DNA braid and allows the construction of a model representing the initial entry of another DNA duplex into the DNA-gate. Steered molecular dynamics calculations suggests the Top2-catalyzed DNA passage may be achieved by a rocker-switch-type movement of the DNA-gate. Structural insights into the gating of DNA passage by the topoisomerase II DNA-gate.,Chen SF, Huang NL, Lin JH, Wu CC, Wang YR, Yu YJ, Gilson MK, Chan NL Nat Commun. 2018 Aug 6;9(1):3085. doi: 10.1038/s41467-018-05406-y. PMID:30082834[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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