title: Structures of the N-linked oligosaccharides of Gp63, the major surface glycoprotein, from Leishmania mexicana amazonensis.
abstract: The extent of protein N-glycosylation in Leishmania mexicana amazonensis has been proposed to be a factor in the virulence of the parasite. The N-linked oligosaccharides of gp63, the major surface glycoprotein of L. mexicana amazonensis, were characterized after their release by hydrazinolysis, re-N-acetylation, and reduction with NaB3H4. High voltage paper electrophoresis of the reduced oligosaccharides revealed only neutral species. Gel-permeation chromatography on Bio-Gel P-4 yielded four fractions, and the oligosaccharides present were structurally characterized by sequential exoglycosidase digestion, fragmentation by acetolysis, and methylation analysis. Four major structures were found and were biantennary oligomannose type with compositions of Glc1Man6GlcNAc2 (La), Man6GlcNAc2 (Lb), Man5GlcNAc2 (Lc), and Man4GlcNAc2 (Ld). The largest oligosaccharide (La) was shown to contain a terminal glucopyranosyl residue on the alpha (1----3) arm. The biantennary oligomannose structures (Lb and Lc) and the glucosylated structure Glc1Man6GlcNAc2 (La) have not previously been reported as a component of a mature glycoprotein from any source.
authors.affiliation: Department of Biochemistry, University of Oxford, United Kingdom.
authors.forename: R W
authors.initials: RW
authors.lastname: Olafson
authors.forename: J R
authors.initials: JR
authors.lastname: Thomas
authors.forename: M A
authors.initials: MA
authors.lastname: Ferguson
authors.forename: R A
authors.initials: RA
authors.lastname: Dwek
authors.forename: M
authors.initials: M
authors.lastname: Chaudhuri
authors.forename: K P
authors.initials: KP
authors.lastname: Chang
authors.forename: T W
authors.initials: TW
authors.lastname: Rademacher
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis*; D002240:Carbohydrate Sequence; D002850:Chromatography, Gel; D007894:Leishmania mexicana / Q000032:analysis*; D008745:Methylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D000953:Antigens, Protozoan; D009844:Oligosaccharides; D014643:Variant Surface Glycoproteins, Trypanosoma