STRUCTURE OF EGGPLANT MOSAIC-VIRUS - EVIDENCE FOR PRESENCE OF LOW-MOLECULAR WEIGHT RNA IN TOP COMPONENT

Three nucleoproteins were found when purified preparations of eggplant mosaic virus (EMV) were submitted to CsCl density gradient centrifugation. The bottom component corresponded to a density .rho. = 1.45 g/ml and a sedimentation coefficient(s) of 106 S. It was infectious [for Nicotiana glutinosa]. High molecular weight EMV-RNA fixes valine and its associated low molecular weight RNA fixes lysine. The top component corresponded to .rho. = 1.26 g/ml and s = 53 S. Each particle contained about 2-3 molecules of RNA of tRNA size able to bind alanine, arginine, histidine, leucine, lysine, phenylalanine, tyrosine and valine. Lysine, arginine and valine accounted, respectively, for 70, 18 and 7% of the total amino acid charge. Small amounts of a 3rd component, sedimenting between bottom and top (.rho. = 1.38 g/ml; s = 70 S) were also found reproducibly in EMV preparations. The nature of this component is not yet known. The biological significance of these findings is discussed.