"Required for polymorphic O-glycosylation of the serine-rich repeat protein in this bacteria. Catalyzes the first step in glycosylation by transferring N-acetylglucosamine from UDP-GlcNAc to serine residues in the substrate protein. Part of the accessory SecA2/SecY2 system specifically required to export serine-rich repeat cell wall proteins usually encoded upstream in the same operon."xsd:string