Structural Basis of α-Fucosidase Inhibition by Iminocyclitols with Ki Values in the Micro- to Picomolar Range

Two loops were found to move inward toward the α‐fucosidase active site to produce a closed conformation of complexes with inhibitors with increasing Ki values from the micro‐ to nanomolar range. Although no further conformational changes in the two loops are observed for inhibitors with sub‐nanomolar Ki values, the loops are additionally stabilized by hydrogen bonds and hydrophobic interactions.