PDBsum entry 1y2t

Sugar binding protein

PDB id: 1y2t

Contents

Protein chains

142 a.a. *

Waters ×168

* Residue conservation analysis

PDB id:

1y2t

Name:

Sugar binding protein

Title:

Crystal structure of the common edible mushroom (agaricus bisporus) lectin

Structure:

Lectin. Chain: a, b

Source:

Agaricus bisporus. Organism_taxid: 5341

Biol. unit:

Tetramer (from PDB file)

Resolution:

1.50Å R-factor: 0.189 R-free: 0.203

Authors:

M.E.Carrizo,S.Capaldi,M.Perduca,F.J.Irazoqui,G.A.Nores,H.L.Monaco

Key ref:

M.E.Carrizo et al. (2005). The antineoplastic lectin of the common edible mushroom (Agaricus bisporus) has two binding sites, each specific for a different configuration at a single epimeric hydroxyl. J Biol Chem, 280, 10614-10623. PubMed id: 15596442 DOI: 10.1074/jbc.M411989200

Date:

23-Nov-04 Release date: 21-Dec-04

Protein chains

Q00022  (ABL_AGABI) -  Agaricus bisporus lectin from Agaricus bisporus

Seq: 143 a.a.

Struc: 142 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1074/jbc.M411989200

J Biol Chem 280:10614-10623 (2005)

PubMed id: 15596442

The antineoplastic lectin of the common edible mushroom (Agaricus bisporus) has two binding sites, each specific for a different configuration at a single epimeric hydroxyl.

M.E.Carrizo, S.Capaldi, M.Perduca, F.J.Irazoqui, G.A.Nores, H.L.Monaco.

ABSTRACT

The lectin from the common mushroom Agaricus bisporus, the most popular edible species in Western countries, has potent antiproliferative effects on human epithelial cancer cells, without any apparent cytotoxicity. This property confers to it an important therapeutic potential as an antineoplastic agent. The three-dimensional structure of the lectin was determined by x-ray diffraction. The protein is a tetramer with 222 symmetry, and each monomer presents a novel fold with two beta sheets connected by a helix-loop-helix motif. Selectivity was studied by examining the binding of four monosaccharides and seven disaccharides in two different crystal forms. The T-antigen disaccharide, Galbeta1-3GalNAc, mediator of the antiproliferative effects of the protein, binds at a shallow depression on the surface of the molecule. The binding of N-acetylgalactosamine overlaps with that moiety of the T antigen, but surprisingly, N-acetylglucosamine, which differs from N-acetylgalactosamine only in the configuration of epimeric hydroxyl 4, binds at a totally different site on the opposite side of the helix-loop-helix motif. The lectin thus has two distinct binding sites per monomer that recognize the different configuration of a single epimeric hydroxyl. The structure of the protein and its two carbohydrate-binding sites are described in detail in this study.

Selected figure(s)

Figure 4.
FIG. 4. The two binding sites in a monomer. Stereodiagram of a monomer of ABL with a molecule of N-acetylgalactosamine (NGA) bound at the T-antigen binding site (top) and a molecule of N-acetylglucosamine (NAG) bound at the second binding site (bottom). The electron density of the 2Fobs-Fc map corresponds to the ligands bound in the orthorhombic form, and it was contoured at the 1.5 level. The side chains of the main amino acids involved in the interactions are represented in the figure. The figure was prepared using the program DINO (www.dino3d.org).

Figure 5.
FIG. 5. Sequence comparison of fungal lectins. The sequences were aligned using the program CLUSTALW (43) and correspond to the following lectins: XCL, X. chrysenteron lectin; PCL, P. cornucopiae lectin; AOL, A. oligospora lectin; PAL, P. anserina lectin; and NCL, N. crassa lectin. The residues involved in the binding of the T antigen to ABL are indicated with a T, and those that participate in the binding of N-acetylglucosamine are indicated with an N. The residues conserved in all the members of the group are represented in red.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2005, 280, 10614-10623) copyright 2005.

Figures were selected by an automated process.