4ux3 | pdb_00004ux3
cohesin Smc3-HD:Scc1-N complex from yeast
Structural highlights
FunctionSMC3_YEAST Involved in chromosome cohesion during cell cycle and in DNA repair. Central component of cohesin complex. The cohesin complex is required for the cohesion of sister chromatids after DNA replication. The cohesin complex apparently forms a large proteinaceous ring within which sister chromatids can be trapped. At anaphase, the complex is cleaved and dissociates from chromatin, allowing sister chromatids to segregate. Publication Abstract from PubMedThrough their association with a kleisin subunit (Scc1), cohesin's Smc1 and Smc3 subunits are thought to form tripartite rings that mediate sister chromatid cohesion. Unlike the structure of Smc1/Smc3 and Smc1/Scc1 interfaces, that of Smc3/Scc1 is not known. Disconnection of this interface is thought to release cohesin from chromosomes in a process regulated by acetylation. We show here that the N-terminal domain of yeast Scc1 contains two alpha helices, forming a four-helix bundle with the coiled coil emerging from Smc3's adenosine triphosphatase head. Mutations affecting this interaction compromise cohesin's association with chromosomes. The interface is far from Smc3 residues, whose acetylation prevents cohesin's dissociation from chromosomes. Cohesin complexes holding chromatids together in vivo do indeed have the configuration of hetero-trimeric rings, and sister DNAs are entrapped within these. Closing the cohesin ring: structure and function of its Smc3-kleisin interface.,Gligoris TG, Scheinost JC, Burmann F, Petela N, Chan KL, Uluocak P, Beckouet F, Gruber S, Nasmyth K, Lowe J Science. 2014 Nov 21;346(6212):963-7. doi: 10.1126/science.1256917. PMID:25414305[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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