Immunochemical studies of turnip yellow mosaic virus—I. Localization of four antigenic regions in the protein subunit

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

“…No data are available on the nature of the antigenic determinants of EMV but a detailed immunological investigation of TYMV is in progress (Pratt et al, 1980;Quesniaux et al, 1983a, b). Three antigenic regions have been identified with antibodies raised against virions.…”

“…The primary structure of its coat protein (Peter et al, 1972) as well as a large part of the nucleotide sequence of its RNA are known (see for instance Guilley & Briand, 1978, and references therein). No high resolution details on its three-dimensional organization are available, but chemical cross-linking has shed some light on the RNA-protein interaction sites (Ehresmann et al, 1980) and several antigenic determinants have been characterized (Pratt et al, 1980;Quesniaux et al, 1983a, b).…”

Turnip yellow mosaic virus isolates with experimentally produced recombinant virion proteins.

“…R9 produced a VP with a surface loop region of the TYMV VP adjacent to the R8 lysine replaced with that of BeMV. This region was shown to have strong antigenic activity in inhibition tests (Pratt et al, 1980), and was predicted by the PP method to be accessible ; R10 produced a VP with the BeMV C terminus. E71 produced a VP with the Plasmodium falciparum epitope replacing seven amino acids at the N terminus of TYMV-BL.…”

“…The resulting recombinants had the following modifications (for amino acid sequences see Table 1) : R1 had the initiating methionine codon of its VP replaced with a stop codon, and would therefore be expected to produce no VP ; R2, R3 and R4 produced VPs with BeMV sequences of different sizes and positions at their N termini. The N terminus has been shown to be a major antigenic determinant in TYMV (Pratt et al, 1980), and was predicted by PP to be accessible ; R5 and R6 produced VPs with the predicted αA and αB helices, respectively, replaced with those of BeMV, although the hydrophobicity moment and PP analyses suggested that the αB helix was only partly within the region changed in the R6 recombinant ; R7 produced a VP with the region of the TYMV VP that cross-linking studies had shown to interact with the viral RNA (Ehresmann et al, 1980) replaced with that of BeMV ; ' R8 ', was a point mutant with a lysine residue found in all sequenced tymovirus VPs changed to asparagine. R9 produced a VP with a surface loop region of the TYMV VP adjacent to the R8 lysine replaced with that of BeMV.…”

“…Early immunochemical studies of TYMV virions and isolated VP showed that the protein had three antigenic determinants (Pratt et al, 1980 ;Quesniaux et al, 1983 a, b) including the N terminus which, it was concluded, was exposed on the surface of the virions. Cross-linking methods also identified three regions of the VP in close contact with the viral RNA (Ehresmann et al, 1980).…”