Structural characterization of the N-glycosylation of individual soybean β-conglycinin subunits.
Soybean (Glycine max) 7S β-conglycinin is a seed storage protein consisting of homo- and hetero-trimers of three subunits, namely α (~67 kDa), α' (~71 kDa), and β (~50 kDa), non-covalently associated. The N-glycans released from the whole β-conglycinin have been already characterized by (1)H NMR some decades ago. Nevertheless, the actual glycosylation of the potential sites and the glycoforms of the individual subunits have not been specifically investigated so far. In this study, up-to-date chromatographic, electrophoretic and mass spectrometric strategies have been combined to achieve the structural characterization of the glycoforms of the three individual β-conglycinin subunits. Glycosylation sites were assigned by analyzing the tryptic glycopeptides of the isolated subunits. Underivatized N-glycans were purified with a two-step clean-up, consisting in sequential reversed-phase and activated porous graphitized carbon micro-chromatography, and profiled by matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS).
Istituto di Scienze dell'Alimentazione (ISA) - CNR, Via Roma 52, 83100 Avellino, Italy.
Gianluca
G
Picariello
Miryam
M
Amigo-Benavent
Maria Dolores
MD
del Castillo
Pasquale
P
Ferranti
D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005916:Globulins / Q000737:chemistry*; D006020:Glycopeptides / Q000737:chemistry*; D006031:Glycosylation; D006108:Graphite / Q000737:chemistry; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D016062:Porosity; D021122:Protein Subunits; D055314:Seed Storage Proteins / Q000737:chemistry*; D016415:Sequence Alignment; D030262:Soybean Proteins / Q000737:chemistry*
D052179:Antigens, Plant; D005916:Globulins; D006020:Glycopeptides; D021122:Protein Subunits; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; D006108:Graphite
Mass spectrometry; N-linked glycans; Porous graphitized carbon micro-chromatography; Soybean; β-Conglycinin