Myristylation of the membrane form of a Trypanosoma brucei variant surface glycoprotein.

A variant surface glycoprotein (VSG) of the parasitic protozoan Trypanosoma brucei was purified following the direct solubilization of trypanosomes in a boiling detergent solution. This material behaved as the amphiphilic membrane form of the glycoprotein previously described (Cardoso de Almeida, M. L., and Turner, M. J. (1983) Nature (Lond.) 302, 349-352). Analysis of this material showed that it contained ester-linked tetradecanoic (myristic) acid. After biosynthetic labeling of trypanosomes with [3H]myristic acid, it was shown that the release of the VSG coat from the parasite membrane, as the soluble form of the VSG, occurred concomitantly with the loss of myristic acid from the glycoprotein. The results suggest that VSG is attached to the parasite membrane via a covalently linked myristic acid-containing lipid moiety.