Interactions of concanavalin A with glycoproteins. A quantitative precipitation study of concanavalin A with the soybean agglutinin.
Certain oligomannose-type glycopeptides have been previously shown to be bivalent for binding to concanavalin A and capable of precipitating the lectin by forming homogeneous cross-linked lattices [L. Bhattacharyya, M. I. Khan, and C.F. Brewer, Biochemistry, 27 (1988) 8762-8767]. In the present study, the effect of protein environment on the binding properties of an oligomannose-type oligosaccharide has been examined through quantitative precipitation analysis of the interactions of concanavalin A (Con A) with the soybean (Glycine max) agglutinin (SBA), which is a tetrameric glycoprotein possessing a single Man9-oligomannose chain per monomer. The results showed that SBA forms two different types of cross-linked complexes with tetrameric Con A, depending on the relative ratio of the two molecules in solution. At a concentration of one equivalent or less, SBA forms a 1:1 complex with Con A. At concentrations exceeding one equivalent, SBA forms a 2:1 complex with Con A. However, SBA forms only 1:1 cross-linked complexes with dimeric forms of Con A, such as acetyl- and succinyl-Con A. The results demonstrated that the total valency of the carbohydrate of SBA is a function of both the quaternary structure of Con A, as well as the relative ratio of SBA to Con A. In addition, the individual Man9-oligosaccharide, which as a glycopeptide is bivalent for binding to Con A, expresses univalency when present on the protein matrix of SBA.
Khan
M I
MI
Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461.
Mandal
D K
DK
Brewer
C F
CF
D002240:Carbohydrate Sequence; D003208:Concanavalin A / Q000378:metabolism*; D003432:Cross-Linking Reagents; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism; D037102:Lectins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D030262:Soybean Proteins; D013025:Glycine max; D010835:Phytohemagglutinins
D003208:Concanavalin A; D003432:Cross-Linking Reagents; D006023:Glycoproteins; D037102:Lectins; D009844:Oligosaccharides; D037121:Plant Lectins; D010940:Plant Proteins; D030262:Soybean Proteins; C028569:oligomannoside; C028824:soybean lectin; D010835:Phytohemagglutinins