9ng0
Human SRCAP-nucleosome complex in the pre-dissociation state of the H2A.Z histone exchange reaction (composite structure)
Structural highlights
DiseaseSRCAP_HUMAN Floating-Harbor syndrome. The disease is caused by mutations affecting the gene represented in this entry. FunctionSRCAP_HUMAN Catalytic component of the SRCAP complex which mediates the ATP-dependent exchange of histone H2AZ/H2B dimers for nucleosomal H2A/H2B, leading to transcriptional regulation of selected genes by chromatin remodeling. Acts as a coactivator for CREB-mediated transcription, steroid receptor-mediated transcription, and Notch-mediated transcription.[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedThe conserved yeast SWR1 and human SRCAP chromatin remodeling complexes catalyze exchange of nucleosomal histone H2A for H2A.Z, but the underlying mechanism has remained obscure. Here, we show that histone exchange by SRCAP requires the transient activator CFDP1 and resolve nine cryo-electron microscopy structures of the SRCAP-CFDP1 holoenzyme that define the stepwise exchange mechanism. CFDP1 recognizes the conformation of the fully engaged SRCAP-nucleosome complex through interactions with multiple subunits-including direct contact with the ATPase domain-and induces conformational transitions that drive extensive DNA unwrapping, eviction of the H2A-H2B dimer, and insertion of the H2A.Z-H2B dimer, all without necessarily requiring hydrolysis of bound ATP. Collectively, these findings provide unprecedented insight into the mechanism of activator- and nucleotide-driven histone exchange from nucleosomal H2A to H2A.Z. Structural mechanism of histone H2A.Z exchange by human SRCAP-CFDP1 holoenzyme.,Park G, Wu C, Louder RK Sci Adv. 2026 Jul 31;12(31):eaei7728. doi: 10.1126/sciadv.aei7728. Epub 2026 Jul , 31. PMID:42536744[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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