The S-Layer Glycoprotein of the CrenarchaeoteSulfolobus acidocaldariusIs Glycosylated at Multiple Sites with Chitobiose-LinkedN-Glycans

[摘要] Glycosylation of the S-layer of the crenarchaeaSulfolobus acidocaldariushas been investigated using glycoproteomic methodologies. The mature protein is predicted to contain 31 N-glycosylation consensus sites with approximately one third being found in the C-terminal domain spanning residuesL1004-Q1395. Since this domain is rich in Lys and Arg and therefore relatively tractable to glycoproteomic analysis, this study has focused on mapping its N-glycosylation. Our analysis identified nine of the 11 consensus sequence sites, and all were found to be glycosylated. This constitutes a remarkably high glycosylation density in the C-terminal domain averaging one site for each stretch of 30–40 residues. Each of the glycosylation sites observed was shown to be modified with a heterogeneous family of glycans, with the largest having a composition Glc1Man2GlcNAc2plus 6-sulfoquinovose (QuiS), consistent with the tribranched hexasaccharide previously reported in the cytochromeb558/566ofS. acidocaldarius.S. acidocaldariusis the only archaeal species whose N-glycans are known to be linked via the chitobiose core disaccharide that characterises the N-linked glycans ofEukarya.

[学科分类] 微生物学和免疫学