Carbohydrate Composition of Variant‐Specific Surface Antigen Glycoproteins from Trypanosoma brucei

Abstract

The carbohydrate of variant-specific surface antigen glycoproteins from bloodstream forms of 13 cloned variants of T. brucei was analyzed by GLC. The glycoproteins contained from 6-17% carbohydrate by weight, and all contained the same 4 sugars: mannose, galactose, glucose and glucosamine (probably as N-acetylglucosamine). The glycoprotein from variant 048 strain 427 contained (.+-. 20%) 11 mannose, 4 galactose, 4 glucose and 5 glucosamine residues/mol of glycoprotein (MW 65,000). Glucose was an integral component of the glycoproteins, not dissociable by sodium dodecyl sulfate, 8 M urea, or 1 M acetic acid. Some of the glucose was dissociated by trichloroacetic acid. Most of the glycoproteins formed precipitin bands with concanavalin A in Ouchterlony double diffusion, but none formed such bands with wheat germ agglutinin or Ricinus communis lectin (MW 120,000).