The N-X-S/T consensus sequence is required but not sufficient for bacterial N-linked protein glycosylation.
In the Gram-negative bacterium Campylobacter jejuni there is a pgl (protein glycosylation) locus-dependent general N-glycosylation system of proteins. One of the proteins encoded by pgl locus, PglB, a homolog of the eukaryotic oligosaccharyltransferase component Stt3p, is proposed to function as an oligosaccharyltransferase in this prokaryotic system. The sequence requirements of the acceptor polypeptide for N-glycosylation were analyzed by reverse genetics using the reconstituted glycosylation of the model protein AcrA in Escherichia coli. As in eukaryotes, the N-X-S/T sequon is an essential but not a sufficient determinant for N-linked protein glycosylation. This conclusion was supported by the analysis of a novel C. jejuni glycoprotein, HisJ. Export of the polypeptide to the periplasm was required for glycosylation. Our data support the hypothesis that eukaryotic and bacterial N-linked protein glycosylation are homologous processes.
Nita-Lazar
Mihai
M
Institute of Microbiology, Department of Biology, Swiss Federal Institute of Technology Zurich, ETH Hönggerberg, CH-8093 Zürich, Switzerland.
Wacker
Michael
M
Schegg
Belinda
B
Amber
Saba
S
Aebi
Markus
M
D020816:Amino Acid Motifs / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D016123:Campylobacter jejuni / Q000235:genetics*; D006031:Glycosylation; D006602:Hexosyltransferases / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics*; D011499:Protein Processing, Post-Translational / Q000235:genetics*; D021381:Protein Transport / Q000235:genetics
D001426:Bacterial Proteins; D008565:Membrane Proteins; D006602:Hexosyltransferases; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase