Glycotyping of Trypanosoma brucei variant surface glycoprotein MITat1.8.
Following a switch from variant surface glycoprotein MITat1.4 to variant surface glycoprotein MITat1.8 expression by Lister strain 427 Trypanosoma brucei brucei parasites, the latter uncharacterized variant surface glycoprotein was analysed. Variant surface glycoprotein MITat1.8 was found to be a disulphide-linked homodimer, containing a complex N-linked glycan at Asn58 and a glycosylphosphatidylinositol membrane anchor attached to Asp419. Mass spectrometric analyses demonstrated that the N-glycan is exclusively Galbeta1-4GlcNAcbeta1-2Manalpha1-3(Galbeta1-4GlcNAcbeta1-2Manalpha1-6)Manbeta1-4GlcNAcbeta1-4GlcNAc and that the conserved Man(3)GlcN-myo-inositol glycosylphosphatidylinositol anchor glycan core is substituted with an average of 4 hexose, most likely galactose, residues. The presence of a complex N-glycan at Asn58 is consistent with the relatively acidic environment of the Asn58 N-glycosylation sequon, that predicts N-glycosylation by T. brucei oligosaccharyltransferase TbSTT3A with a Man(5)GlcNAc(2) structure destined for processing to a paucimannose and/or complex N-glycan (Izquierdo L, Schulz B, Rodrigues JA et al. EMBO J 2009;28:2650-61 [12]).
Mehlert
Angela
A
Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom.
Sullivan
Lauren
L
Ferguson
Michael A J
MA
D000818:Animals; D002240:Carbohydrate Sequence; D017261:Glycosylphosphatidylinositols / Q000032:analysis; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000032:analysis; D055503:Protein Multimerization; D051381:Rats; D014346:Trypanosoma brucei brucei / Q000737:chemistry* / Q000302:isolation & purification; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000737:chemistry*
D017261:Glycosylphosphatidylinositols; D011134:Polysaccharides; D014643:Variant Surface Glycoproteins, Trypanosoma