Analysis of lettuce necrotic yellows virus structural proteins with monoclonal antibodies and concanavalin A.

Three major structural proteins of lettuce necrotic yellow virus (LNYV) were identified by discontinuous polyacrylamide gel electrophoresis (PAGE) to have Mr approximately 78,000 (G), 57,000 (N), and 19,000 (M). Unreduced G and M proteins had faster mobilities in PAGE indicating the presence of disulfide bonds. The G protein was shown to be glycosylated with a complex network of oligosaccharides containing beta-N-acetylchitobiose N-linked to asparagine residues of the protein. Up to 17 additional minor bands were also detected in silver-stained electrophoretograms. In Western immunoblots, 9 of these (Mr approximately 27,000-220,000) were recognized by a monoclonal antibody to the N protein and another 6 (Mr approximately 58,000-180,000) with a monoclonal antibody to the G protein, indicating that they were degradation products or aggregates of these two viral proteins. Two minor silver-stained bands failed to react with either of the monoclonal antibodies, but were recognized by polyclonal anti-LNYV serum and are probably the L (Mr approximately 190,000) and NS (Mr approximately 38,000) viral proteins.