Two antiviral proteins, gp35 and gp22, correspond to beta-1,3-glucanase and an isoform of PR-5

Two antivirally active, TMV-inducible, tobacco proteins (gp22 and gp35) were recently isolated by immunoaffinity chromatography using monoclonal antibodies to human interferon- beta . The proteins were characterized by determining the partial amino acid sequence of the amino termini of the proteins and of several cyanogen bromide-derived peptides. At the time of characterization, these proteins were found to be unique and not homologous to known protein sequences on available databases. However, in a recent search of protein sequence information from our own database on TMV-inducible proteins (J. Ryals et al., unpublished database) and from the Gen-Bank and EMBL databases, we have found that gp 35 corresponds to the basic, vacuolar form of beta -1,3-glucanase from tobacco and gp22 is closely related to both the acidic and basic forms of pathogenesis-related protein 5 (i.e. PR-5), from tobacco.