Interaction and mixed aggregation of proteins from Tobacco mosaic virus strains

Abstract

Proteins from four strains of TMV, namely vulgare, flavum, dahlemense and Holmes’ rib grass, were electrophoretically examined singly and in pairs at different hydrogen ion concentrations. In weakly alkaline media an average of six polypeptide chains of TMV-protein remain associated together, while constant dissociation and reassociation takes place. This dynamic state of equilibrium is responsible for transient reciprocal associations of proteins or polypeptide chains from the first three TMV-strains. On lowering the pH value, these interacting proteins form mixed aggregates with intermediate mobilities. Protein from the fourth strain, Holmes’ rib grass, when tested against the strain, vulgare, neither showed any interaction in alkaline media nor formed mixed aggregates. Factors determining the formation of mixed aggregates and the possible relationship among the four strains have been discussed.