ACF (for ATP-utilising chromatin assembly and remodelling factor) is a chromatin-remodelling complex that catalyses the ATP-dependent assembly of periodic nucleosome arrays. The WAC (WSTF/Acf1/cbp146) domain is an approximately 110-residue module present at the N-termini of Acf1-related proteins in a variety of organisms. The DNA-binding region of Acf1 includes the WAC domain, which is necessary for the efficient binding of ACF complex to DNA.