Figure 1: Overall structure of AmyPΔSBD.

(a) AmyPΔSBD consists of domains A (shown in gray), B(shown in magenta) and C(shown in blue). Disulfide bridges are shown in orange. Calcium ions are shown as hot pink spheres. Catalytic residues are shown as red sticks. (b) Structural comparison of active sites of AmyPΔSBD and GTA (pdb accession code 4e2o) shows the absence of a protruding lid above the active site for AmyPΔSBD. The lid in GTA (shown in violet) is involved in the stabilization of the substrate. The catalytic residues are shown in red.