Concanavalin A distorts the  -GlcNAc-(1->2)-Man linkage of  -GlcNAc-(1->2)- -Man-(1->3)-[ -GlcNAc-(1->2)- -Man-(1->6)]-Man upon binding

Abstract

Carbohydrate recognition by proteins is a key event in many biological processes. Concanavalin A is known to specifically recognize the pentasaccharide core (beta-GlcNAc-(1-->2)-alpha- Man-(1-->3)-[beta-GlcNAc-(1-->2)-alpha-Man-(1-->6)]-Man) of N-linked oligosaccharides with a Ka of 1.41 x 10(6 )M-1. We have determined the structure of concanavalin A bound to beta-GlcNAc-(1-->2)-alpha-Man-(1-->3)-[beta-GlcNAc-(1-->2)-alpha-Man- (1-->6)]-Man to 2.7A. In six of eight subunits there is clear density for all five sugar residues and a well ordered binding site. The pentasaccharide adopts the same conformation in all eight subunits. The binding site is a continuous extended cleft on the surface of the protein. Van der Waals interactions and hydrogen bonds anchor the carbohydrate to the protein. Both GlcNAc residues contact the protein. The GlcNAc on the 1-->6 arm of the pentasaccharide makes particularly extensive contacts and including two hydrogen bonds. The binding site of the 1-->3 arm GlcNAc is much less extensive. Oligosaccharide recognition by Con A occurs through specific protein carbohydrate interactions and does not require recruitment of adventitious water molecules. The beta-GlcNAc-(1-->2)-Man glycosidic linkage PSI torsion angle on the 1-->6 arm is rotated by over 50 degrees from that observed in solution. This rotation is coupled to disruption of interactions at the monosaccharide site. We suggest destabilization of the monosaccharide site and the conformational strain reduces the free energy liberated by additional interactions at the 1-->6 arm GlcNAc site.

Honey and royal jelly, like human milk, abrogate lectin-dependent infection-preceding Pseudomonas aeruginosa adhesion

“…Con A tagging of additional gps between 36 and 105 kDa, observed in the more loaded western blots might be due to their terminal N-acetylglucosamine (GlcNAc) residues and internal Man residues, to which only Con A, but not PA-IIL, binds (Moothoo and Naismith, 1998).…”

The Crystal Structures of Man(α1–3)Man(α1-O)Me and Man(α1–6)Man(α1-O)Me in Complex with Concanavalin A

“…It is expelled only when the trimannose M3M6M binds. When a still larger oligosaccharide binds to ConA, the pentasaccharide GlcNAc-(␤1-2)Man(␣1-3)[GlcNAc(␤1-2)Man(␣1-6)]Man (14), another conserved water molecule, is expelled. This water is found for both the M6M⅐ConA subunit A and MeMan⅐ConA structures in the empty subsites for the N-acetylglucosamine on the ␣1-6-linked arm.…”

“…ConA 1 is the most extensively studied legume lectin. The crystal structures of the complexes of ConA with a series of carbohydrates have been solved: methyl-␣-D-mannopyranoside (10) and methyl-␣-D-glucopyranoside (11), Man(␣1-3)[Man(␣1-6)]Man (which is the trimannoside ConA epitope of N-linked carbohydrates) (12,13), the pentasaccharide GlcNAc(␤1-2)Man(␣1-3)[GlcNAc(␤1-2)Man(␣1-6)]Man (14), and the dimannoside Man(␣1-2)Man(␣1-O)Me (15). In this work, we describe the interactions of Man(␣1-6)Man(␣1-O)Me and Man(␣1-3)Man(␣1-O)Me, the two dimannoside parts of the highly specific ConA epitope Man(␣1-3)[Man(␣1-6)]Man(␣1-O)Me, with ConA.…”

Electromagnetophoretic Force Measurement of a Single Binding Interaction between Lectin and Yeast Cell Surfaces

“…6,7 In the present study, we focused on the oligosaccharide-protein interaction, which plays a key role in cellular recognition. 8,9 Concanavalin A (Con A) is a well characterized lectin, which has oligosaccharide-binding proteins. 10 Con A has the binding specificity to mannose.…”