PglL_A is a pilin glycosylation ligase domain found in Gram negative bacteria [1]. PglL protein O-oligosaccharyltransferases differ from the wider Wzy_C family, Pfam:PF04932, which contains both WaaL O-antigen ligases, in its substrate-specificity. PglL O-oligosaccharyltransferases (O-OTase) transfer oligosaccharide to serine or threonine in a protein. A further indication that the genes identified are PglL rather than WaaL homologues is that they are not located within lipopolysaccharide biosynthetic loci [2]. The specific pilin glycosylation ligases are a subset of the more general bacterial protein o-oligosaccharyltransferases [2].

1: Pilin glycosylation in Neisseria meningitidis occurs by a similar pathway to wzy-dependent O-antigen biosynthesis in Escherichia coli. Power PM, Seib KL, Jennings MP; Biochem Biophys Res Commun. 2006;347:904-908. PMID:16870136

2: Identification of bacterial protein o-oligosaccharyltransferases and their glycoprotein substrates. Schulz BL, Jen FE, Power PM, Jones CE, Fox KL, Ku SC, Blanchfield JT, Jennings MP; PLoS One. 2013;8:e62768. PMID:23658772