Title
Prospecting for microbial α-N-acetylgalactosaminidases yields a new class of GH31 O-glycanase
Author
Peter Rahfeld, Jacob F. Wardman, Kevin Mehr, Drew Huff, Connor Morgan-Lang, Hong-Ming Chen, Steven J. Hallam, Stephen G. Withers
Year
2019
Journal
Journal of Biological Chemistry
Abstract
α-Linked GalNAc (α-GalNAc) is most notably found at the nonreducing terminus of the blood type–determining A-antigen and as the initial point of attachment to the peptide backbone in mucin-type O-glycans. However, despite their ubiquity in saccharolytic microbe-rich environments such as the human gut, relatively few α-N-acetylgalactosaminidases are known. Here, to discover and characterize novel microbial enzymes that hydrolyze α-GalNAc, we screened small-insert libraries containing metagenomic DNA from the human gut microbiome. Using a simple fluorogenic glycoside substrate, we identified and characterized a glycoside hydrolase 109 (GH109) that is active on blood type A-antigen, along with a new subfamily of glycoside hydrolase 31 (GH31) that specifically cleaves the initial α-GalNAc from mucin-type O-glycans. This represents a new activity in this GH family and a potentially useful new enzyme class for analysis or modification of O-glycans on protein or cell surfaces.
Full Article
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Protein folding, Biochemistry