title: Weak calcium-mediated interactions between Lewis X-related trisaccharides studied by NMR measurements of residual dipolar couplings.
abstract: 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.
authors.affiliation: Département de Chimie, associé au CNRS, Ecole Normale Supérieure, 24, rue Lhomond, 75231 Paris Cedex 05, France.
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Nodet
authors.forename: Luisa
authors.initials: L
authors.lastname: Poggi
authors.forename: Daniel
authors.initials: D
authors.lastname: Abergel
authors.forename: Chafika
authors.initials: C
authors.lastname: Gourmala
authors.forename: Dengxiang
authors.initials: D
authors.lastname: Dong
authors.forename: Yongmin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jean-Maurice
authors.initials: JM
authors.lastname: Mallet
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Bodenhausen
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry; D002118:Calcium / Q000737:chemistry*; D002240:Carbohydrate Sequence; D017666:Deuterium Oxide; D016256:Lewis X Antigen / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011522:Protons; D012996:Solutions; D014312:Trisaccharides / Q000737:chemistry*
chemical_list: D016256:Lewis X Antigen; D011522:Protons; D012996:Solutions; D014312:Trisaccharides; D017666:Deuterium Oxide; D002118:Calcium; D000117:Acetylglucosamine