23Na NMR study of the interaction between hyaluronan and the bications Ca(++), Mg(++) and Cu(++).
The relaxation rate R = pi Delta nu(1/2) of the quadrupolar (23)Na nucleus was measured at pH approximately 7 using a 200 MHz NMR spectrometer with a view to observe the interaction between hyaluronan and its natural counterion Na(+) and the bications Ca(++), Mg(++) and Cu(++). An interpretation of our results, by means of the "entropy of fluctuations" concept of Na(+), is presented. We show that Cu(++) ions are more effective than Ca(++) and Mg(++). A possible model of complexation of Cu(++) in a cage formed by the 1-4 glycosidic bond, the carboxylate side-chain and the acetoamide side-chain is proposed, according to electrostatic potential computations using the ZINDO1 quantum semi empirical method.
Adrian-Scotto
M
M
Laboratoire de Biophysique, Université de Nice-Sophia Antipolis, Parc Valrose-06108 Nice Cedex 2, France.
Guibbolini
M
M
Mallet
G
G
Gaysinski
M
M
Vasilescu
D
D
D002118:Calcium; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002413:Cations, Divalent / Q000737:chemistry*; D003300:Copper; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry* / Q000302:isolation & purification; D008274:Magnesium; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D012964:Sodium; D014312:Trisaccharides / Q000737:chemistry; D014470:Umbilical Cord / Q000737:chemistry
D002413:Cations, Divalent; D014312:Trisaccharides; D003300:Copper; D006820:Hyaluronic Acid; D012964:Sodium; D008274:Magnesium; D002118:Calcium