Characterization of two African swine fever virus 220-kDa proteins: a precursor of the major structural protein p150 and an oligomer of phosphoprotein p32.

Two kinds of unrelated African swine fever virus proteins of 220 kDa have been identified by means of two-dimensional gel electrophoresis and immunoprecipitation analysis. One species, named pp220 and identified as the precursor of the major structural protein p150, was found to be a moderately acidic protein (pl near 7) expressed after the replication of the viral DNA. The second species, a cluster of 220-kDa proteins with slightly different isoelectric points (pl ranging from 5 to 6), was found to be a homooligomeric complex formed by an early 32-kDa protein. This component was identified as the viral phosphoprotein p32, the most immunogenic early protein of African swine fever virus. A detailed characterization of its oligomeric structure is reported.