PDBsum entry: 2iho

Sugar binding protein

PDB id: 2iho

Contents

Protein chain

292 a.a. *

Ligands

NAG-GAL-GAL ×2

Waters ×170

* Residue conservation analysis

PDB id:

2iho

Name:

Sugar binding protein

Title:

Crystal structure of moa, a lectin from the mushroom marasmi in complex with the trisaccharide gal(1,3)gal(1,4)glcnac

Structure:

Lectin. Chain: a. Synonym: agglutinin. Engineered: yes

Source:

Marasmius oreades. Organism_taxid: 181124. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.41Å R-factor: 0.192 R-free: 0.211

Authors:

E.Grahn,G.Askarieh,A.Holmner,H.Tateno,H.C.Winter,I.J.Goldste U.Krengel

Key ref:

E.Grahn et al. (2007). Crystal structure of the marasmius oreades mushroom lectin in complex with a xenotransplantation epitope. J Mol Biol, 369, 710-721. PubMed id: 17442345 DOI: 10.1016/j.jmb.2007.03.016

Date:

27-Sep-06 Release date: 22-May-07

Protein chain

Q8X123  (Q8X123_9AGAR) -  Agglutinin

Seq: 293 a.a.

Struc: 292 a.a.

 Gene Ontology (GO) functional annotation 

• Biochemical function: metal ion binding (1 term)

DOI no: 10.1016/j.jmb.2007.03.016

J Mol Biol 369:710-721 (2007)

PubMed id: 17442345

Crystal structure of the marasmius oreades mushroom lectin in complex with a xenotransplantation epitope.

E.Grahn, G.Askarieh, A.Holmner, H.Tateno, H.C.Winter, I.J.Goldstein, U.Krengel.

ABSTRACT

MOA, a lectin from the mushroom Marasmius oreades, is one of the few reagents that specifically agglutinate blood group B erythrocytes. Further, it is the only lectin known to have exclusive specificity for Galalpha(1,3)Gal-containing sugar epitopes, which are antigens that pose a severe barrier to animal-to-human organ transplantation. We describe here the structure of MOA at 2.4 A resolution, in complex with the linear trisaccharide Galalpha(1,3)Galbeta(1,4)GlcNAc. The structure is dimeric, with two distinct domains per protomer: the N-terminal lectin module adopts a ricinB/beta-trefoil fold and contains three putative carbohydrate-binding sites, while the C-terminal domain serves as a dimerization interface. This latter domain, which has an unknown function, reveals a novel fold with intriguing conservation of an active site cleft. A number of indications suggest that MOA may have an enzymatic function in addition to the sugar-binding properties.

Selected figure(s)

Figure 1.
Figure 1. A stereo representation of the MOA carbohydrate-binding site in complex with the trisaccharide Galα(1,3)Galβ(1,4)GlcNAc. (a) The sugar ligand (black) bound to the α-site and the residues important for sugar binding are shown as stick models. The experimental electron density map (F[obs]) is contoured at 1.0 σ. (b) An overview of the protein–ligand interactions in the α-site. The trisaccharide (red) and the residues involved in direct and indirect hydrogen bonds (cutoff at 3.4 Å) are shown as stick models. Water molecules (W) are depicted as blue spheres. (c) A corresponding overview of the protein–ligand interactions in the β-site. This Figure as well as Figures 2(a), (b), (d), 3 and 4 were made using PyMoL [http://pymol.sourceforge.net/].

Figure 3.
Figure 3. Comparison of the binding sites. (a) Superimposed backbone trace for the three binding sites α (blue), β (green) and γ (pink). The backbone trace is embedded in a surface representation of the α-site shown in light gray. For Asp40 and the residues exhibiting the largest differences in sugar binding, the side-chains are included in the picture. Likewise, the bound trisaccharides are shown as black (α-site) and grey (β-site) stick models. (b) A close-up view of the salt-bridge between Asp40 in the α-site loop and Lys265 from the C-terminal domain.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2007, 369, 710-721) copyright 2007.

Figures were selected by an automated process.