Fig. 2.

Sequence alignment and overall structure of Rds3p. (A) Sequence alignment of human and yeast Rds3p. Components of the structure are shown above the sequence, using the same color code as in 2C (K, zinc knuckle; β, β-hairpin; S, strand; H, helix; L, loop; numbers denote fingers 1, 2, and 3). (B) Ribbon stereoview of the Rds3p structure in chainbow coloring (corresponding to the rainbow color gradient bar in 2A) with the β-triangle facing downwards (180° rotation from Fig. 1). Sidechains of the metal-binding cysteine residues are shown numbered. (C) Schematic showing how Rds3p is built from three GATA-like zinc fingers (shown in same orientation as B). In Rds3p, each β-hairpin is broken and replaced by a strand (magenta) running from one finger to the next, and a loop (orange) is added from the α-helix of one finger to the zinc-knuckle of the next. The zinc knuckle of finger 3 is “interrupted.” (D) Simplest representation of the origin of the knot in the Rds3p structure (same orientation as in B and C).