Classification of LARGE-liked GlcNAc-transferases of Dictyostelium discoideum by phylogenetic analysis

GlcNAc transferases are important enzymes involved in protein glycosylation, a cellular process controlling life-time, location and function of proteins. Previously, four new genes in Dictyostelium discoideum through a forward genetic screening, and BLASP search are annotated as gnt12 (GlcNAc Transferase), gnt13, gnt14, and gnt15 since their deduced amino acid sequences share significant similarity to mammalian LARGE, a GlcNAC glycosyltransferase involved on the functional maturation of alpha-dystroglycan, a key molecule associated with human muscular dystrophy. However, the four genes of Dicystelium are not included in CAZy (Carbohydrate-Active enZymes) database, in which glycosyltransferases were classified based on structural, reaction mechanism and sequence similarities. Here we presented our bioinformatics analysis workflow based on phylogentic analysis to determine if these four genes are in related to the glycosyltransferase 2 and/or 49 families. And, we have also provided the experimental evidence with altered glycosylation pattern in the genetic engineered mutant of gnt 15(-).