Characterization of the protein Components of Turnip Mosaic Virus

Abstract

Polyacrylamide gel electrophoresis of the dissociated protein of turnip mosaic virus (TuMV) in the presence of sodium dodecyl sulfate (SDS) revealed three components designated as light form (LF) (MW 24, 000), middle form (MF) (MW 26, 000), and heavy form (HF) (MW 33, 000). Among them, the LF protein appeared only when TuMV purified from freezed (-21C, 7 days) leaf materials was used for protein dissociation. The MF protein, which always appeared associating with HF, was considered to be a breakdown product of the HF protein caused by proteolytic activity during storage. The HF protein behaved anomalously on SDS-polyacrylamide gel electrophoresis by using various gel concentrations. On the basis of amino acid analysis and peptide mapping, the protein subunit of TuMV, each subunit having a molecular weight of approximately 27, 500, was shown to be consisted of about 239 amino acid residues.