Comparison of ΔYY1 with other zinc-finger
structures. (A) Amino acid sequence of ΔYY1. The zinc
fingers are aligned one above the other, with the linker regions
separated by vertical bars. Amino acids are numbered as in ref. 14. The
ΔYY1–DNA contacts (Y1–Y4, •, backbone contact; +, base
contact; =, touches both base and backbone) are also presented
schematically with those seen in the structures of Zif268 (Z1–Z3)
(18), GLI (G2–G5) (16), and Tramtrack (T1, T2) (21). Between the
alignment panels, the zinc-finger consensus sequence (Ø, aromatic
residue) and the conserved secondary structure elements are provided.
Detailed comparisons of the ΔYY1 fingers with those of Zif268 and GLI
reveal significant similarities [Y1 versus G3 root-mean-square
deviation (rmsd) = 0.81 Å, Y2 versus Z3 rmsd = 0.61 Å, Y3 versus
G3 rmsd = 0.73 Å, and Y4 versus G3 rmsd = 0.68 Å, which
compare favorably with comparisons between Zif268 and GLI].
(B) Schematic comparison of the DNA contacts made by Zif268,
GLI, and ΔYY1. DNA bases and backbone are represented by rectangles
and circles, respectively. Hatched rectangles and solid circles denote
sites of protein contact.