PMID:17890310

Citation	Faridmoayer, A, Fentabil, MA, Mills, DC, Klassen, JS and Feldman, MF (2007) Functional characterization of bacterial oligosaccharyltransferases involved in O-linked protein glycosylation. J. Bacteriol. 189:8088-98
Abstract	Protein glycosylation is an important posttranslational modification that occurs in all domains of life. Pilins, the structural components of type IV pili, are O glycosylated in Neisseria meningitidis, Neisseria gonorrhoeae, and some strains of Pseudomonas aeruginosa. In this work, we characterized the P. aeruginosa 1244 and N. meningitidis MC58 O glycosylation systems in Escherichia coli. In both cases, sugars are transferred en bloc by an oligosaccharyltransferase (OTase) named PglL in N. meningitidis and PilO in P. aeruginosa. We show that, like PilO, PglL has relaxed glycan specificity. Both OTases are sufficient for glycosylation, but they require translocation of the undecaprenol-pyrophosphate-linked oligosaccharide substrates into the periplasm for activity. Whereas PilO activity is restricted to short oligosaccharides, PglL is able to transfer diverse oligo- and polysaccharides. This functional characterization supports the concept that despite their low sequence similarity, PilO and PglL belong to a new family of "O-OTases" that transfer oligosaccharides from lipid carriers to hydroxylated amino acids in proteins. To date, such activity has not been identified for eukaryotes. To our knowledge, this is the first report describing recombinant O glycoproteins synthesized in E. coli.
Links	PubMed PMC2168655 Online version:10.1128/JB.01318-07
Keywords	Acetyltransferases/chemistry; Acetyltransferases/genetics; Acetyltransferases/metabolism; Bacterial Proteins/chemistry; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Escherichia coli/genetics; Glycosylation; Neisseria meningitidis/enzymology; Neisseria meningitidis/genetics; Periplasm/metabolism; Polysaccharides/metabolism; Pseudomonas syringae/enzymology; Pseudomonas syringae/genetics
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
PSEAI:Q51353		GO:0004576: oligosaccharyl transferase activity	ECO:0000314:		F		Figure 1a shows that the pilO knockout mutant is incapable of producing glycosylated pillin, whereas the wild-type strain did produce glycosylated pillin. Figure 1a shows the picture of the gel from western-blot analysis of whole cell extracts from both the wild-type strain and the pilO mutatnt containing unglycosylated and glycosylated pillin.	complete CACAO 8050
PSEAI:Q51353	enables	GO:0004576: oligosaccharyl transferase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
NEIME:G1FG65	involved_in	GO:0006493: protein O-linked glycosylation	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
NEIME:G1FG65		GO:0006493: protein O-linked glycosylation	ECO:0000314:		P		Figure 3a shows that E. coli transformed with a plasmid encoding PglL showed a band of lower electrophoretic mobility, which indicates glycosylation of MC pilin, where E. coli not transformed with the plasmid shows no glycosylation.	complete CACAO 9901

References

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