Extended Data Fig. 5: Change in metal binding site and crossing angle.
From: Efficient Lewis acid catalysis of an abiological reaction in a de novo protein scaffold
a, b, Comparison of the metal binding sites of MID1 (a) and DA7 (b). MID1 coordinates the Zn(II) ion (yellow sphere) with three histidine residues (grey sticks). A fourth non-coordinating histidine points away from the metal binding site. H35C and H39V mutations (orange sticks) altered the coordination sphere of the catalytic Zn(II) ion during evolution. c, Overlay of parental MID1 (grey) and DA7 (orange) shows the decrease in crossing angle of the two helix-turn-helix fragments by > 30°. d, Calculated acute crossover angles θ between helices H1–H4 of MID1 and DA7W16S.
