Practice question

Chromatin remodeling complexes use ATP hydrolysis to translocate along DNA and alter histone-DNA contacts. Core subunits contain Snf2-like superfamily 2 helicase translocase domains with ATPase activity, coupled to DNA binding and directionally pumping DNA around octamer. In SWI/SNF, ISWI, CHD and INO80 families, the translocase pulls DNA from linker region, generating torsional strain, transient loop or bulge propagation, resulting in sliding or ejection. This DNA translocase activity is distinct from HAT or methyltransferase chemistry and underlies nucleosome repositioning, exposing regulatory sequences to transcription factors and polymerases.