Table 2.

DNA-binding ensemble

SCOP classification	Core size	RMSD	Core description
Classic size finger (C2H2) family	20	1.2	β-hairpin followed by an α-helix
Nucleosome core histones family	65	1.4	a bundle of three helices
Phage repressors family	60	0.9	five helices
Restriction endonuclease-like superfamily	55	1.9	β-sheet of five strands and two helices
Winged helix DNA-binding domain superfamily	46	1.7	a bundle of three helices and a small β-sheet (wing)

The structural core detected by MASS for each of the five different structural subgroups listed in Table 1.