6h2x
MukB coiled-coil elbow from E. coli
Structural highlights
FunctionMUKB_ECOLI Plays a central role in chromosome condensation, segregation and cell cycle progression. Functions as a homodimer, which is essential for chromosome partition. Involved in negative DNA supercoiling in vivo, and by this means organizes and compacts chromosomes. May achieve or facilitate chromosome segregation by condensation of DNA from both sides of a centrally located replisome during cell division. Stimulates both DNA relaxation and to a lesser extent decatenation activity of topoisomerase IV.[1] [2] Publication Abstract from PubMedStructural maintenance of chromosomes (SMC)-kleisin complexes organize chromosomal DNAs in all domains of life, with key roles in chromosome segregation, DNA repair and regulation of gene expression. They function through the entrapment and active translocation of DNA, but the underlying conformational changes are largely unclear. Using structural biology, mass spectrometry and cross-linking, we investigated the architecture of two evolutionarily distant SMC-kleisin complexes: MukBEF from Escherichia coli, and cohesin from Saccharomyces cerevisiae. We show that both contain a dynamic coiled-coil discontinuity, the elbow, near the middle of their arms that permits a folded conformation. Bending at the elbow brings into proximity the hinge dimerization domain and the head-kleisin module, situated at opposite ends of the arms. Our findings favour SMC activity models that include a large conformational change in the arms, such as a relative movement between DNA contact sites during DNA loading and translocation. A folded conformation of MukBEF and cohesin.,Burmann F, Lee BG, Than T, Sinn L, O'Reilly FJ, Yatskevich S, Rappsilber J, Hu B, Nasmyth K, Lowe J Nat Struct Mol Biol. 2019 Mar;26(3):227-236. doi: 10.1038/s41594-019-0196-z. Epub, 2019 Mar 4. PMID:30833788[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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