PDBsum entry 1fay

Sugar binding protein

PDB id: 1fay

Contents

Protein chains

(+ 2 more) 236 a.a. *

Ligands

NAG-NAG ×6

AMG ×8

Metals

_CA ×8

_MN ×8

Waters ×80

* Residue conservation analysis

PDB id:

1fay

Name:

Sugar binding protein

Title:

Winged bean acidic lectin complexed with methyl-alpha-d-galactose (monoclinic form)

Structure:

Acidic lectin. Chain: a, b, c, d, e, f, g, h. Synonym: acidic agglutinin

Source:

Psophocarpus tetragonolobus. Winged bean. Organism_taxid: 3891. Organ: leguminous seeds. Other_details: winged bean, psophocarpus tetragonolobus, seeds

Biol. unit:

60mer (from PQS)

Resolution:

3.30Å R-factor: 0.204 R-free: 0.242

Authors:

N.Manoj,V.R.Srinivas,A.Surolia,M.Vijayan,K.Suguna

Key ref:

N.Manoj et al. (2000). Carbohydrate specificity and salt-bridge mediated conformational change in acidic winged bean agglutinin. J Mol Biol, 302, 1129-1137. PubMed id: 11183779 DOI: 10.1006/jmbi.2000.4111

Date:

14-Jul-00 Release date: 14-Jul-01

Protein chains

Q9SM56  (Q9SM56_PSOTE) -  Winged bean acidic lectin (Fragment) from Psophocarpus tetragonolobus

Seq: 240 a.a.

Struc: 236 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

DOI no: 10.1006/jmbi.2000.4111

J Mol Biol 302:1129-1137 (2000)

PubMed id: 11183779

Carbohydrate specificity and salt-bridge mediated conformational change in acidic winged bean agglutinin.

N.Manoj, V.R.Srinivas, A.Surolia, M.Vijayan, K.Suguna.

ABSTRACT

Structures of two crystal forms of the dimeric acidic winged bean agglutinin (WBAII) complexed with methyl-alpha-D-galactose have been determined at 3.0 A and 3.3 A resolution. The subunit structure and dimerisation of the lectin are similar to those of the basic lectin from winged bean (WBAI) and the lectin from Erythrina corallodendron (EcorL). The conformation of a loop and its orientation with respect to the rest of the molecule in WBAII are, however, different from those in all the other legume lectins of known structure. This difference appears to have been caused by the formation of two strategically placed salt bridges in the former. Modelling based on the crystal structures provides a rationale for the specificity of the lectin, which is very different from that of WBAI, for the H-antigenic determinant responsible for O blood group reactivity. It also leads to a qualitative explanation for the thermodynamic data on sugar-binding to the lectin, with special emphasis on the role of a tyrosyl residue in the variable loop in the sugar-binding region in generating the carbohydrate specificity of WBAII.

Selected figure(s)

Figure 2.
Figure 2. Superposition of the C^a traces of legume lectins conA, GS4, WBAI, EcorL, PNA, DBL, lentil lectin, soybean agglutinin, phytohemagglutinin L & WBAII. WBAII is shown in black.

Figure 5.
Figure 5. (a) Stereo view of the interactions of H-type II trisaccharide in conformation I with protein atoms in WBAII. Loop D of EcorL is shown in grey. (b) Stereo view of the interactions of H-type II trisaccharide in conformation II with protein atoms in WBAII. Loop D of EcorL is shown in grey.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2000, 302, 1129-1137) copyright 2000.

Figures were selected by an automated process.