Crystal Structure of the GalNAc/Gal-Specific Agglutinin from the Phytopathogenic Ascomycete Sclerotinia sclerotiorum Reveals Novel Adaptation of a β-Trefoil Domain
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- 作者：Gerlind Sulzenbacher ; Vé ; ronique Roig-Zamboni ; Willy J. Peumans ; Pierre Rougé ; Els J.M. Van Damme ; Yves Bourne
- 关键词：fungal lectin ; crystallography ; galactose ; β ; -trefoil domain ; glycan array
- 刊名：Journal of Molecular Biology
- 出版年：2010
- 出版时间：23 July 2010
- 年：2010
- 卷：400
- 期：4
- 页码：715-723
- 全文大小：931 K
文摘
A lectin from the phytopathogenic ascomycete Sclerotinia sclerotiorum that shares only weak sequence similarity with characterized fungal lectins has recently been identified. S. sclerotiorum agglutinin (SSA) is a homodimeric protein consisting of two identical subunits of 17 kDa and displays specificity primarily towards Gal/GalNAc. Glycan array screening indicates that SSA readily interacts with Gal/GalNAc-bearing glycan chains. The crystal structures of SSA in the ligand-free form and in complex with the Gal-β1,3-GalNAc (T-antigen) disaccharide have been determined at 1.6 and 1.97 Å resolution, respectively. SSA adopts a β-trefoil domain as previously identified for other carbohydrate-binding proteins of the ricin B-like lectin superfamily and accommodates terminal non-reducing galactosyl and N-acetylgalactosaminyl glycans. Unlike other structurally related lectins, SSA contains a single carbohydrate-binding site at site α. SSA reveals a novel dimeric assembly markedly dissimilar to those described earlier for ricin-type lectins. The present structure exemplifies the adaptability of the β-trefoil domain in the evolution of fungal lectins.