NAG-thiazoline (NGT) and its derivatives are well-known inhibitors against most β-acetylglucosaminidases (β-GlcNAcases) except for insect and bacterial chitinolytic β-GlcNAcases, including the molting-indispensable OfHex1 from the insect Ostrinia furnacalis. Here, we report the co-crystal structure of OfHex1 in complex with NGT. This structure reveals a large active pocket in OfHex1 that may account for the poor inhibitory activity of NGT. To test this hypothesis, a bulky substituent was designed and synthesized on the thiazoline ring of NGT. The resulting compound (NMAGT) was determined to be a submicromolar inhibitor of OfHex1 with a Ki value of 0.13 μM, which is 600-fold lower than Ki value of NGT. Molecular dynamics simulation analysis supported the good fit of NMAGT to the active pocket.
Keywords: Chitinolytic enzyme; Inhibitor; NGT; β-Acetylglucosaminidase.
Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.