Molecular cloning, expression, and characterization of a novel endo-α-N-acetylgalactosaminidase from Enterococcus faecalis

We report here the molecular cloning, expression and characterization of a novel endo-α-N-acetylgalactosaminidase, classified into the GH101 family, from Enterococcus faecalis (endo-EF). The recombinant endo-EF was found to catalyze the liberation of core1-disaccharides (Galβ1-3GalNAc) from core1-pNP (Galβ1-3GalNAcα-pNP) like other GH101 family enzymes. However, endo-EF seems to differ in specificity from the GH101 enzymes reported to date, because it was able to release trisaccharides from core2-pNP (Galβ1-3[GlcNAcβ1-6]GalNAcα-pNP) and tetrasaccharides from Gal-core2-pNP (Galβ1-3[Galβ1-3GlcNAcβ1-6]GalNAcα-pNP). Interestingly, the enzyme could transfer not only core1-disaccharides but also core2-trisaccharides to alkanols generating alkyl-oligosaccharides. Endo-EF should facilitate O-glycoprotein research.