Active-pocket size differentiating insectile from bacterial chitinolytic β-N-acetyl-D-hexosaminidases

Chitinolytic beta-N-acetyl-D-hexosaminidase is a branch of the GH20 (glycoside hydrolase family 20) beta-N-acetyl-D-hexosaminidases that is only distributed in insects and micro-organisms, and is therefore a potential target for the action of insecticides. PUGNAc [O-(2-acetamido-2-deoxy-D-glucopyransylidene)-amino-N-phenylcarbamate] was initially identified as an inhibitor against GH20 beta-N-acetyl-D-hexosaminidases. So far no crystal structure of PUGNAc in complex with any GH20 beta-N-acetyl-D-hexosaminidase has been reported. We show in the present study that the sensitivities of chitinolytic fi-N-acetyl-D-hexosaminidases towards PUGNAc can vary by 100-fold, with the order being OfHex 1 (Ostrinia furnacalis beta-N-acetyl-D-hexosaminidase)