PDBsum entry 2dty

Sugar binding protein

PDB id: 2dty

Contents

Protein chains

237 a.a. *

Ligands

NAG-FUC-NAG ×6

NAG-NAG-BMA-FUC

NAG-FUL-NAG

A2G ×4

Metals

_CA ×4

_MN ×4

Waters ×276

* Residue conservation analysis

PDB id:

2dty

Name:

Sugar binding protein

Title:

Crystal structure of basic winged bean lectin complexed with n-acetyl- d-galactosamine

Structure:

Basic agglutinin. Chain: a, b, c, d. Synonym: wba i

Source:

Psophocarpus tetragonolobus. Winged bean. Organism_taxid: 3891

Resolution:

2.65Å R-factor: 0.196 R-free: 0.239

Authors:

K.A.Kulkarni,S.Katiyar,A.Surolia,M.Vijayan,K.Suguna

Key ref:

K.A.Kulkarni et al. (2006). Structural basis for the carbohydrate-specificity of basic winged-bean lectin and its differential affinity for Gal and GalNAc. Acta Crystallogr D Biol Crystallogr, 62, 1319-1324. PubMed id: 17057334 DOI: 10.1107/S0907444906028198

Date:

19-Jul-06 Release date: 07-Nov-06

Protein chains

O24313  (LEC1_PSOTE) -  Basic agglutinin from Psophocarpus tetragonolobus

Seq: 242 a.a.

Struc: 237 a.a.

DOI no: 10.1107/S0907444906028198

Acta Crystallogr D Biol Crystallogr 62:1319-1324 (2006)

PubMed id: 17057334

Structural basis for the carbohydrate-specificity of basic winged-bean lectin and its differential affinity for Gal and GalNAc.

K.A.Kulkarni, S.Katiyar, A.Surolia, M.Vijayan, K.Suguna.

ABSTRACT

The crystal structure of the complexes of basic winged-bean lectin with galactose, 2-methoxygalactose, N-acetylgalactosamine and methyl-alpha-N-acetylgalactosamine have been determined. Lectin-sugar interactions involve four hydrogen bonds and a stacking interaction in all of the complexes. In addition, an N-H...O hydrogen bond involving the hydroxyl group at C2 exists in the galactose and 2-methoxygalactose complexes. An additional hydrophobic interaction involving the methyl group in the latter leads to the higher affinity of the methyl derivative. In the lectin-N-acetylgalactosamine complex the N-H...O hydrogen bond is lost, but a compensatory hydrogen bond is formed involving the O atom of the acetamido group. In addition, the CH(3) moiety of the acetamido group is involved in hydrophobic interactions. Consequently, the 2-methyl and acetamido derivatives of galactose have nearly the same affinity for the lectin. The methyl group alpha-linked to the galactose takes part in additional hydrophobic interactions. Therefore, methyl-alpha-N-acetylgalactosamine has a higher affinity than N-acetylgalactosamine for the lectin. The structures of basic winged-bean lectin-sugar complexes provide a framework for examining the relative affinity of galactose and galactosamine for the lectins that bind to them. The complexes also lead to a structural explanation for the blood-group specificity of basic winged-bean lectin.

Selected figure(s)

Figure 1.
Figure 1 Dimeric structure of WBAI complexed with galactose. Ca^2+ and Mn^2+ are shown in spheres. Galactose and N-linked glycans are shown in stick representation. This figure was produced using PyMOL (http://www.pymol.org ).

Figure 4.
Figure 4 Schematic representation of blood-group determinants.

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2006, 62, 1319-1324) copyright 2006.

Figures were selected by an automated process.