| 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 PubMed
Type 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
- ↑ West KL, Meczes EL, Thorn R, Turnbull RM, Marshall R, Austin CA. Mutagenesis of E477 or K505 in the B' domain of human topoisomerase II beta increases the requirement for magnesium ions during strand passage. Biochemistry. 2000 Feb 15;39(6):1223-33. PMID:10684600
- ↑ Kitagawa H, Fujiki R, Yoshimura K, Mezaki Y, Uematsu Y, Matsui D, Ogawa S, Unno K, Okubo M, Tokita A, Nakagawa T, Ito T, Ishimi Y, Nagasawa H, Matsumoto T, Yanagisawa J, Kato S. The chromatin-remodeling complex WINAC targets a nuclear receptor to promoters and is impaired in Williams syndrome. Cell. 2003 Jun 27;113(7):905-17. PMID:12837248
- ↑ Chen SF, Huang NL, Lin JH, Wu CC, Wang YR, Yu YJ, Gilson MK, Chan NL. Structural insights into the gating of DNA passage by the topoisomerase II DNA-gate. Nat Commun. 2018 Aug 6;9(1):3085. doi: 10.1038/s41467-018-05406-y. PMID:30082834 doi:http://dx.doi.org/10.1038/s41467-018-05406-y
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