1. Diversity in prokaryotic glycosylation: an archaeal-derived N-linked glycan contains legionaminic acid
- Author
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Kandiba, Lina, Aitio, Olli, Helin, Jari, Guan, Ziqiang, Permi, Perttu, Bamford, Dennis H., Eichler, Jerry, and Roine, Elina
- Subjects
carbohydrates (lipids) ,Archaeal Viruses ,Viral Proteins ,Glycosylation ,Polysaccharides ,viruses ,Molecular Sequence Data ,Sialic Acids ,Amino Acid Sequence ,Haloferax volcanii ,Peptide Mapping ,Article ,Mass Spectrometry - Abstract
VP4, the major structural protein of the haloarchaeal pleomorphic virus, HRPV-1, is glycosylated. To define the glycan structure attached to this protein, oligosaccharides released by β-elimination were analysed by mass spectrometry and nuclear magnetic resonance spectroscopy. Such analyses showed that the major VP4-derived glycan is a pentasaccharide comprising glucose, glucuronic acid, mannose, sulphated glucuronic acid and a terminal 5-N-formyl-legionaminic acid residue. This is the first observation of legionaminic acid, a sialic acid-like sugar, in an archaeal-derived glycan structure. The importance of this residue for viral infection was demonstrated upon incubation with N-acetylneuraminic acid, a similar monosaccharide. Such treatment reduced progeny virus production by half 4 h post infection. LC-ESI/MS analysis confirmed the presence of pentasaccharide precursors on two different VP4-derived peptides bearing the N-glycosylation signal, NTT. The same sites modified by the native host, Halorubrum sp. strain PV6, were also recognized by the Haloferax volcanii N-glycosylation apparatus, as determined by LC-ESI/MS of heterologously expressed VP4. Here, however, the N-linked pentasaccharide was the same as shown to decorate the S-layer glycoprotein in this species. Hence, N-glycosylation of the haloarchaeal viral protein, VP4, is host-specific. These results thus present additional examples of archaeal N-glycosylation diversity and show the ability of Archaea to modify heterologously expressed proteins.
- Published
- 2012