CHEMICAL SUBUNIT OF TOBACCO RINGSPOT VIRUS COAT PROTEIN

The coat protein of tobacco ringspot virus (TRSV) dissociated in the presence of sodium dodecyl sulphate (SDS), urea, and 2-mercaptoethanol (MCE) separated into six components on electrophoresis in polyacrylamide gels. It was established that none of the components was a protein of host plant origin and that they were all chemically and antigenically similar. The estimated molecular weights of the components ranged from about 14,000 to more than 110,000, approximating a polymeric series of 1, 2, 3, 4, and 8; over 85% of the protein was recovered in a band with a molecular weight of about 57,000. These data, together with the amino acid composition of the protein and the results of tryptic peptide mapping experiments, indicate that the TRSV capsid is constructed from a single polypeptide species containing 119 amino acid residues with a molecular weight of 12,988. These results are discussed in relation to capsomeric models of the TRSV protein shell. © 1979.