EXPRESSION OF A 32-KILODALTON THEILERIA-SERGENTI PIROPLASM SURFACE PROTEIN BY RECOMBINANT BACULOVIRUSES

Previous studies detected a single amino acid substitution (Ala(196) t o Gly(196)) between cDNA clones encoding a 32 kDa antigen (p32) of The ileria sergenti (Chitose stock) obtained from a persistently infected calf. In this study, 2 different recombinant baculoviruses (pAc/p32-Al a(196) and pAc/p32-Gly(196)) were constructed for the expression of p3 2. Molecular masses of the polypeptides produced in Spodoptera frugipe rda cells infected with the recombinant baculoviruses were the same as that of authentic p32. pAc/p32-Ala(196) produced additional polypepti des, with molecular masses higher than 32 kDa, which resulted from dif ferential N-glycosylation as revealed by endo N-glycosidase treatment. The results indicate that a single amino acid substitution may lead t o a conformational change in p32 which affected posttranslational modi fication of recombinant products.