Identification of the catalytic residues of the first family of beta(1-3)glucanosyltransferases identified in fungi

A new family of glycosylphosphatidylinositol-anchored beta(1-3)glucanosyltr ansferases (Gelp), recently identified and characterized in the filamentous fungus Aspergillus fumigatus, showed functional similarity to the Gas/Phr/ Epd protein families, which are involved in yeast morphogenesis. Sequence c omparisons and hydrophobic cluster analysis (HCA) showed that all the Gas/P hr/Epd/Gel proteins belong to a new family of glycosylhydrolases, family 72 . We confirmed by site-directed mutagenesis and biochemical analysis that t he two conserved glutamate residues (the putative catalytic residues of thi s family, as determined by HCA) are involved in the active site of this fam ily of glycosylhydrolases.