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.
Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461.
M I
MI
Khan
D K
DK
Mandal
C F
CF
Brewer
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