2y9y
From Proteopedia
Chromatin Remodeling Factor ISW1a(del_ATPase)
Structural highlights
FunctionISW1_YEAST Catalytic component of ISW1-type complexes, which act by remodeling the chromatin by catalyzing an ATP-dependent alteration in the structure of nucleosomal DNA. They are involved in coordinating transcriptional repression, activation and elongation phases. The ISW1A complex represses gene expression at initiation through specific positioning of a promoter proximal dinucleosome. The ISW1B complex acts within coding regions to control the amount of RNA polymerase II released into productive elongation and to coordinate elongation with termination and pre-mRNA processing.[1] [2] [3] [4] Publication Abstract from PubMedSite-specific recognition of DNA in eukaryotic organisms depends on the arrangement of nucleosomes in chromatin. In the yeast Saccharomyces cerevisiae, ISW1a and related chromatin remodelling factors are implicated in establishing the nucleosome repeat during replication and altering nucleosome position to affect gene activity. Here we have solved the crystal structures of S. cerevisiae ISW1a lacking its ATPase domain both alone and with DNA bound at resolutions of 3.25 A and 3.60 A, respectively, and we have visualized two different nucleosome-containing remodelling complexes using cryo-electron microscopy. The composite X-ray and electron microscopy structures combined with site-directed photocrosslinking analyses of these complexes suggest that ISW1a uses a dinucleosome substrate for chromatin remodelling. Results from a remodelling assay corroborate the dinucleosome model. We show how a chromatin remodelling factor could set the spacing between two adjacent nucleosomes acting as a 'protein ruler'. Structure and mechanism of the chromatin remodelling factor ISW1a.,Yamada K, Frouws TD, Angst B, Fitzgerald DJ, DeLuca C, Schimmele K, Sargent DF, Richmond TJ Nature. 2011 Apr 28;472(7344):448-53. PMID:21525927[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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