Partial determination of the primary structure of a variant surface glycoprotein from Trypanosoma equiperdum. Composition and location of a carbohydrate moiety.
Salivarian trypanosomes have the ability to evade the immune response of their hosts by the sequential expression of different cell surface glycoproteins. Among the isolated specific antigens from cloned variants of Trypanosoma equiperdum, a structural study was undertaken on two immunologically cross-reacting variant surface glycoproteins, and results concerning the basic antigenic type are reported. The glycoprotein was cleaved by cyanogen bromide, and amino acids of several purified fractions obtained by gel filtration chromatography of this cleavage mixture were sequenced by automated Edman degradation. Sequencing in particular allowed the identification of the N-terminal portion of the molecule (residues 1-74). Sugar compositions of the fractions have demonstrated the presence of at least two carbohydrate moieties in the glycoprotein. Using a subsequent enzymatic subcleavage we were able to locate the first glycosylation site in position 57. An important observation was that the first oligosaccharide identified was rich in mannose and devoid of galactose.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D003488:Cyanogen Bromide; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000032:analysis*; D008970:Molecular Weight; D014345:Trypanosoma / Q000032:analysis*; D014643:Variant Surface Glycoproteins, Trypanosoma
D000596:Amino Acids; D002241:Carbohydrates; D006023:Glycoproteins; D014643:Variant Surface Glycoproteins, Trypanosoma; D003488:Cyanogen Bromide