Highlights • Swc2-Z is a specific Swc2 region interacting with the nucleosome acidic patch • Swc2-Z facilitates the disassembly of the inherently unstable H2A nucleosome • H2A and H2A.Z residues in M4 regions affect nucleosome stability • Loss of Swc2-Z decreases SWR1 activity in vitro and in vivo Summary The multisubunit chromatin remodeler SWR1/SRCAP/p400 replaces the nucleosomal H2A-H2B dimer with the free-form H2A.Z-H2B dimer, but the mechanism governing the unidirectional H2A-to-H2A.Z...