Partial Characterization of a Vicilin-Like Glycoprotein from Seeds of Flowering Tobacco (Nicotiana sylvestris)

[摘要] A vicilin-like glycoprotein from the seeds ofNicotiana sylvestris, flowering tobacco, has been identified using nanoLC/ESI-MS/MS. Sequences from a fragment of protein demonstrated homology with vicilins from other members of the Solanaceae family, notably potato (Solanum demissum). Reducing and nonreducing SDS-PAGE analyses of the identified protein indicated that fragments resulting from in situ proteolytic processing are joined byintrachain disulphide bonds. Staining with Con A lectin was specifically inhibited by mannose suggested the presence ofN-linked glycosylation which was confirmed by carbohydrate compositional analysis of PVDF-bound protein subunits. HPAEC-PAD analysis of the monosaccharides released from the glycoprotein by acid hydrolysis revealed glucosamine and mannose.N-acetylglucosamine termination of attached oligosaccharides was further verified by inhibitable WGA lectin staining. Immunostaining of PVDF-boundN. sylvestrisproteins with antibodies againstG. maxtotal protein demonstrated cross-staining at masses corresponding to fragments from the proteolytically processed protein subunits.

[学科分类] 植物学