How does allosamidin bind to human macrophage chitinase?

The structural interactions of allosamidin with family 18 chitinases have been previously determined by x-ray crystallography. The inhibitor is known to bind from the -3 to -1 subsites.

Allosamidin binds in a groove on the human chitinase, occupying subsites -3 to -1, with the allosamizoline moiety occupying the -1 subsite. Tight interactions are formed with the allosamizoline, which is lined with conserved residues. Specifically, Trp-358 stacks with the allosamizoline's hydrophobic face, and residues like Tyr-27, Phe-58, Gly-98, Ala-183, Met-210, and Met-356 contribute to a hydrophobic pocket for its methyl groups. Hydrogen bonds are also formed, for example, with Asp-138, Trp-99, Tyr-212, and Asp-213.