Further evidence for multiple proteins in the foot-and-mouth disease virus particle

Animal Virus Research Institute, Pirbright, Surrey Further evidence has been obtained which confirms that foot-and-mouth disease virus contains several structural proteins. By electrophoresis in urea-polyacrylamide gels, virus of type O gave six distinct bands. In sodium dodecyl sulphate-polyacrylamide gels four proteins with molecular weights of 34, 30, 26 and 13.5 x 10 3 were clearly demonstrated. When virus preparations were labelled with a single amino acid, in both sodium dodecyl sulphate-polyacrylamide and urea-polyacrylamide gel electrophoresis, the fastest migrating protein contained no arginine and only traces of cysteine. This protein also stained differently from the other bands with Coomassie Blue and was absent from the 12s protein subunit prepared by mild acid (pH 6.5) disruption of the virus. This protein was separated from the 12s subunit by sucrose gradient centrifugation and by ion exchange chromatography on Amberlite IRC-50. Received 8 March 1971; accepted 1 June 1971.