Characterization of mevalonate-labeled lipids isolated from parasite proteins in Schistosoma mansoni.

Adult paired schistosomes incubated for 3 days in radiolabeled mevalonate can effectively label at least 2 major proteins with apparent sizes of 25 and 43 kDa. The 25-kDa mevalonate-labeled proteins comigrated with proteins that could be labeled with GTP. The lipids attached to these proteins were removed and resolved by HPLC and found to comigrate with known samples of farnesol and geranylgeraniol. Homogenates of the schistosome when incubated with labeled farnesol pyrophosphate effectively labeled a protein(s) with an apparent molecular weight of 43 kDa while homogenates incubated in the presence of labeled geranylgeranyl pyrophosphate-labeled schistosome proteins with an apparent molecular weight of 25 kDa. Our results demonstrate that Schistosoma mansoni has the ability to covalently attach farnesol and geranylgeranyl to low-molecular weight proteins.