Why two are not enough: degradation of p-toluenesulfonate by a bacterial community from a pristine site in Moorea, French Polynesia

It has been demonstrated previously that Enterococcus faecalis produces secreted endoglycosidases that enable the bacteria to remove N-linked glycans from glycoproteins. One enzyme potentially responsible for this activity is EF0114, comprising a typical GH18 endoglycosidase domain and a GH20 domain. We have analyzed the other candidate, EF2863, and show that this predicted single domain GH18 protein is an endo-β-N-acetylglucosaminidase. EF2863 hydrolyzes the glycosidic bond between two N-acetylglucosamines (GlcNAc) in N-linked glycans of the high-mannose and hybrid type, releasing the glycan and leaving one GlcNAc attached to the protein. The activity of EF2863 is similar to that of the well known deglycosylating enzyme EndoH from Streptomyces plicatus. According to the CAZy nomenclature, the enzyme is designated EfEndo18A.