The Relationships of Certain Tymoviruses Assessed from the Amino Acid Composition of Their Coat Proteins

Abstract

The amino acid composition of the coat proteins of the following viruses is reported: Andean potato latent, clitoria yellow vein, desmodium yellow mottle, dulcamara mottle, eggplant mosaic, okra mosaic, ononis yellow mosaic, scrophularia mottle, and, as controls, cocksfoot mild mosaic and cocksfoot mottle viruses. These data, together with some already published, were used to compute classifications of the tymoviruses. These classifications show a general similarity to Koenig’s serological classification of the tymoviruses, but the correlation is poor, unlike similar comparisons of tobamovirus classifications. Several possible reasons for the poor correlation have been examined and excluded, and its implications are discussed.

Serological Relationships among Tombusviruses

“…Gibbs & A. Mackenzie, unpublished results) or similarities between coat protein compositions (Paul et al, 1980).…”

Guidelines for the Identification and Characterization of Plant Viruses

“…The amino acid composition of the coat proteins of a number of viruses is known but is of little use in distinguishing between similar viruses, because similar compositions may arise from quite different sequences. There is more agreement between relationships suggested by amino acid composition and serology in the tobamovirus group than in the tymovirus group (Paul et al, 1980a). Better comparisons may be made using 'peptide maps' obtained by limited proteolysis of purified protein followed by gel electrophoresis (Cleveland et al, 1977).…”

Comparisons between the Primary Structure of the Coat Proteins of Turnip Yellow Mosaic Virus and Eggplant Mosaic Virus

“…Neither of the two sequences contains a region rich in basic residues able to undergo strong ionic interactions with the RNA, and the amino acid composition of other tymovirus coat proteins (Paul et al, 1980) makes it likely to be a general property of the family. Such regions, deeply embedded in the RNA, have been found in several small viruses stabilized by strong RNA-protein interactions (for reviews, see Rossmann et al, 1983;Harrison, 1983).…”