The HAND domain adopts a secondary structure consisting of four alpha helices, three of which (H2, H3, H4) form an L-like configuration. Helix H2 runs antiparallel to helices H3 and H4, packing closely against helix H4, whilst helix H1 reposes in the concave surface formed by these three helices and runs perpendicular to them. The domain confers DNA and nucleosome binding properties to the protein [1].

1: Crystal structure and functional analysis of a nucleosome recognition module of the remodeling factor ISWI. Grune T, Brzeski J, Eberharter A, Clapier CR, Corona DF, Becker PB, Muller CW; Mol Cell. 2003;12:449-460. PMID:14536084