1y2v

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Template:STRUCTURE 1y2v

Crystal structure of the common edible mushroom (Agaricus bisporus) lectin in complex with T-antigen

Overview

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.

About this Structure

1Y2V is a Single protein structure of sequence from Agaricus bisporus. Full crystallographic information is available from OCA.

Reference

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., Carrizo ME, Capaldi S, Perduca M, Irazoqui FJ, Nores GA, Monaco HL, J Biol Chem. 2005 Mar 18;280(11):10614-23. Epub 2004 Dec 13. PMID:15596442 Page seeded by OCA on Sat May 3 15:49:10 2008