Figure 2.

(A) The structure of a DHQS monomer shown in cartoon format to indicate the positions of the proximal elements PE1–PE3, the distal element DE3, and helix α8. (B) A closeup cut-away view of a DHQS monomer showing the positions of the site-directed mutants. Blue, open form with cyan showing the mutated residues; red, closed form with pink showing the mutated residues; green, B-chain of the open form; purple, N-chain of the closed form. R105 is not shown, as there is no single viewpoint that allows all the mutated residues to be shown. The section of the closed form used PDB model 1dqs and the open form PDB 1nrx.