6yvd
From Proteopedia
Head segment of the S.cerevisiae condensin holocomplex in presence of ATP
Structural highlights
FunctionCND2_YEAST Regulatory subunit of the condensin complex, a complex required for conversion of interphase chromatin into mitotic-like condense chromosomes. The condensin complex probably introduces positive supercoils into relaxed DNA in the presence of type I topoisomerases and converts nicked DNA into positive knotted forms in the presence of type II topoisomerases. The condensin complex probably also plays a role during interphase.[1] [2] Publication Abstract from PubMedComplexes containing a pair of structural maintenance of chromosomes (SMC) family proteins are fundamental for the three-dimensional (3D) organization of genomes in all domains of life. The eukaryotic SMC complexes cohesin and condensin are thought to fold interphase and mitotic chromosomes, respectively, into large loop domains, although the underlying molecular mechanisms have remained unknown. We used cryo-EM to investigate the nucleotide-driven reaction cycle of condensin from the budding yeast Saccharomyces cerevisiae. Our structures of the five-subunit condensin holo complex at different functional stages suggest that ATP binding induces the transition of the SMC coiled coils from a folded-rod conformation into a more open architecture. ATP binding simultaneously triggers the exchange of the two HEAT-repeat subunits bound to the SMC ATPase head domains. We propose that these steps result in the interconversion of DNA-binding sites in the catalytic core of condensin, forming the basis of the DNA translocation and loop-extrusion activities. Cryo-EM structures of holo condensin reveal a subunit flip-flop mechanism.,Lee BG, Merkel F, Allegretti M, Hassler M, Cawood C, Lecomte L, O'Reilly FJ, Sinn LR, Gutierrez-Escribano P, Kschonsak M, Bravo S, Nakane T, Rappsilber J, Aragon L, Beck M, Lowe J, Haering CH Nat Struct Mol Biol. 2020 Jul 13. pii: 10.1038/s41594-020-0457-x. doi:, 10.1038/s41594-020-0457-x. PMID:32661420[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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