The crystal structure of a plant lectin in complex with the Tn antigen.

Alvaro Babino (1) , Diana Tello (2) , Adriana Rojas (2) , Sylvie Bay (3) , Eduardo Osinaga (1) , Pedro Maria Alzari (2)

1 Universidad de Montevideo
2 Biochimie Structurale
3 Chimie Organique

The structure of the tetrameric Vicia villosa isolectin B4 (VVLB4) in complex with a cancer antigen, the Tn glycopeptide (GalNAc-O-Ser), was determined at 2.7 A resolution. The N-acetylgalactoside moiety of the ligand binds to the primary combining site of VVLB4 in a similar way as observed for other Gal/GalNAc-specific plant lectins. The amino acid moiety of the Tn antigen is largely exposed to the solvent and makes few contacts with the protein. The structure of the complex provides a framework to understand the differences in the strength of VVLB4 binding to different sugars and emphasizes the role of a single protein residue, Tyr127, as a structural determinant of Tn-binding specificity.

Domaines: Sciences du Vivant [q-bio]

Alvaro Babino, Diana Tello, Adriana Rojas, Sylvie Bay, Eduardo Osinaga, et al.. The crystal structure of a plant lectin in complex with the Tn antigen.. FEBS Letters, 2003, 536 (1-3), pp.106-10. ⟨10.1016/S0014-5793(03)00037-1⟩. ⟨pasteur-00166854⟩