A single amino acid mutation alters the capsid protein electrophoretic double-band phenotype of the Plum pox virus strain PPV-Rec
Z. W. S ubr, S. Novakova, A. Nagyova, M. Glasa
Institute of Virology, Slovak Academy of Sciences, Dubravska 9, 84505 Bratislava, Slovakia
M. Kamencayova, J. Nosek
Faculty of Natural Sciences, Commenius University, Mlynska dolina, 84215 Bratislava, Slovakia
Plum pox virus (PPV) isolates differ by their capsid protein (CP) mobility in SDS-PAGE. These electrophoretic phenotypes are likely to result from posttranslational modifications of the CP. We demonstrated that the CP mobility was solely determined by the CP N-terminal region. Sequence comparison pinpointed a possible role of mutations at position 66 in determining the CP phenotype of PPV-Rec isolates. Site-directed mutagenesis of a chimeric clone demonstrated that Gly(66) in the CP resulted in the double-band phenotype, while Arg(66) led to a single-band CP pattern, possibly by preventing the phosphorylation of a nearby Ser residue by steric hindrance.