Mechanistic and structural analysis of a family 31 ?-glycosidase and its lycosyl-enzyme intermediate

Lovering, Andrew L., Lee, Seung Seo, Kim, Young-Wan, Withers, Stephen G., Strynadka, Natalie C. and Hughes, Howard (2005) Mechanistic and structural analysis of a family 31 ?-glycosidase and its lycosyl-enzyme intermediate. The Journal of Biological Chemistry, 280 (3), 2105-2115. (doi:10.1074/jbc.M410468200).

Abstract

We have determined the first structure of a family 31 ?-glycosidase, that of YicI from Escherichia coli, both free and trapped as a 5-fluoroxylopyranosyl-enzyme intermediate via reaction with 5-fluoro-?-D-xylopyranosyl fluoride. Our 2.2-Å resolution structure shows an intimately associated hexamer with structural elements from several monomers converging at each of the six active sites. Our kinetic and mass spectrometry analyses verified several of the features observed in our structural data, including a covalent linkage from the carboxylate side chain of the identified nucleophile Asp416 to C-1 of the sugar ring. Structure-based sequence comparison of YicI with the mammalian ?-glucosidases lysosomal ?-glucosidase and sucrase-isomaltase predicts a high level of structural similarity and provides a foundation for understanding the various mutations of these enzymes that elicit human disease.

This record has no associated files available for download.

Contributors

Author: Seung Seo Lee

Download statistics