Catalytic component of the SWR1 complex which mediates the ATP-dependent exchange of histone H2A for the H2A variant HZT1 leading to transcriptional regulation of selected genes by chromatin remodeling. ATP + H2O = ADP + H(+) + phosphate Component of the SWR1 chromatin-remodeling complex. Belongs to the SNF2/RAD54 helicase family. SWR1 subfamily.