[Electrophoretic analysis of the proteins of different alphavirus strains].

Proteins of various alphavirus strains: Venezuelan equine encephalomyelitis, Semliki Forest, and Sindbis, were studied by a high resolution polyacrylamide gel electrophoresis. In addition to structural C, E1 and E2 proteins, the infected cells were found to contain a number of nonstructural polypeptides: B, 83 kD (analogue of nsP2), 75 kD (nsP3), PE2, precursor of E2 and a product of modification of nucleocapsid protein C27. In virions, in addition to the main structural polypeptides, protein components with molecular weights about 100 kD were found which, most likely, were aggregates of E1/E2 glycoproteins, and 40 kD, a product of E1 protein degradation. The alphavirus strains under study differed both in the electrophoretic mobility of the above-mentioned virus-specific polypeptides and in the stability of B and PE2 proteins in the infected cells. The intracellular stability of polyprotein B depended considerably also on the host cell.