Characterization of carbohydrate-binding specificity of concanavalin A by competitive binding of pyridylamino sugar chains.
Carbohydrate-binding specificity of Con A was characterized by competitive binding studies of pyridylamino (PA) sugar chains. PA-derivatives of 17 oligomannose-type sugar chains, Man1-9GlcNAc2-PA, and those of three complex-type sugar chains were used as ligands. The ratios of bound and free sugar concentrations, [LS]/[S], were determined by means of microequilibrium dialysis followed by high performance liquid chromatography as already reported [Mega, T. & Hase, S. (1991) J. Biochem. 109, 600-603]. The association constant, Ka, was calculated from [LS]/[S] of a sugar chain and that of a standard sugar chain by using the equation Ka = Ka0 x ([S0]/[LS0]) x ([LS]/[S]), where Ka0, [S0], and [LS0] are the association constant, and the free and bound ligand concentrations of the standard sugar chain, respectively. This calculation was effective for the determination of Ka of ligands with similar affinities to the standard sugar chain. The carbohydrate structures with highest affinity for Con A among those tested were found to be: [formula: see text]
Mega
T
T
Department of Chemistry, Osaka University College of Science.
Oku
H
H
Hase
S
S
D000606:Amino Sugars / Q000737:chemistry*; D000631:Aminopyridines / Q000737:chemistry*; D001667:Binding, Competitive; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D003208:Concanavalin A / Q000737:chemistry*; D008969:Molecular Sequence Data
D000606:Amino Sugars; D000631:Aminopyridines; D003208:Concanavalin A