Polypeptide composition of poliovirions, naturally occurring empty capsids, and 14S precursor particles.

The three serotypes of poliovirus were compared with respect to their polypeptide composition. Type 1, 2, and 3 strains were clearly different from each other in the electrophoretic mobilities of their larger structural polypeptides. Some of the viral polypeptides formerly identified as single peaks (e.g., VP 2) were shown to contain multiple components, indicating that purified virions contain at least six polypeptides. Three type 1 strains were indistinguishable in their viral polypeptides. A quantitative estimate was made of the polypeptide composition of the type 1 Mahoney poliovirion, as well as of naturally occurring empty capsids and 14S precursor particles. The data are discussed in light of the antigenic differences among polioviruses and the possible modes of virion morphogenesis.