Figure 3
Comparison of the active sites of NnGH92 (blue) and Bt3990 (pink) with α-mannosidase inhibitors. The Bt3990–MSM complex (PDB entry 2ww3) was superimposed on the NnGH92–ManI complex using PyMOL and its built-in cealign function. The calcium ion is coloured black. (a) The general acid (Glu944/533) and two general bases Asp1056/642 and Asp1058/644 align at equivalent positions. At the −1 subsite, the mannose ring of ManI aligns with the nonreducing end of MSM. (b) Amino-acid residues shaping the binding subsites and interacting with the ligands. At the +1 subsite, Leu793 in NnGH92 was in an equivalent position to Cys393 in Bt3990, whereas the other residues were highly conserved in similar orientations. The structures were visualized using PyMOL (version 2.3.2; Schrödinger). |