The Coat Protein of the Alliaria Strain of Turnip Mosaic Virus: Molecular Weight and Degradation Products Formed During Purification and Upon Storage

Abstract

SUMMARY Protein obtained by degradation of particles of the ‘Alliaria’ strain of TuMV (AlTuMV) was heterogeneous. Polyacrylamide gel electrophoresis experiments showed that this heterogeneity is greatly increased when purified virus suspensions are stored for 60 h in 0.02 m-borate buffer, pH 7.5, at 4 °C instead of being immediately degraded with 1% sodium dodecyl sulphate (SDS). When freshly purified virus particles were degraded, the protein preparations contained three components, I, II and III (estimated mol. wt. 38000, 30000 and 27500, respectively) whose relative amounts differed between samples of virus. It is suggested that components II and III, which both react against AlTuMV antiserum, are produced by degradation of component I. Electrophoresis in the presence of urea at different gel concentrations indicated that components I, II and III observed in the polyacrylamide-SDS system differ both in mol. wt. and in charge density.