Weak calcium-mediated interactions between Lewis X-related trisaccharides studied by NMR measurements of residual dipolar couplings.

Gabrielle Nodet (1) , Luisa Poggi (2) , Daniel Abergel (3) , Chafika Gourmala (2) , Dengxiang Dong (2) , Yongmin Zhang (2, 4) , Jean-Maurice Mallet (3) , Geoffrey Bodenhausen (3, 5)

1 Département de Chimie - ENS Paris
2 BIOSYMA - Biomolécules : synthèse, structure et mode d'action (UMR 8642)
3 UPMC - Université Pierre et Marie Curie - Paris 6
4 ZJU-ENS Joint Laboratory of Medicinal Chemistry,
5 ISIC - Institut des sciences et d'ingénierie chimiques

The Lewis X (LeX) determinant, a trisaccharide with the carbohydrate sequence Galbeta(1-->4)[Fucalpha(1-->3)]GlcNAcbeta, is believed to be responsible for Ca2+-mediated cell-cell interactions. In partly oriented phases composed of mixtures of penta(ethyleneglycol)monododecyl ether HO(CH2CH2O)5C12H25 and n-hexanol in the presence of Ca2+ ions, the variation of the residual dipolar couplings 1DCH of various CiHi vectors in LeX as a function of the concentration of the trisaccharide demonstrates the existence of very weak LeX-Ca2+-LeX complexes in solution. Synthetic 3-, 4-, and 6-deoxy-LeX variants were also shown to form complexes in the presence of calcium ions, despite the replacement of one of their hydroxyl groups by hydrogen atoms. This is the first direct observation in solution of a calcium-mediated interaction between LeX molecules.

Domaines: Chimie organique

Gabrielle Nodet, Luisa Poggi, Daniel Abergel, Chafika Gourmala, Dengxiang Dong, et al.. Weak calcium-mediated interactions between Lewis X-related trisaccharides studied by NMR measurements of residual dipolar couplings.. Journal of the American Chemical Society, 2007, 129 ((29)), pp.9080-5. ⟨10.1021/ja0711056⟩. ⟨hal-00689908⟩