Hyaluronic Acid

Macromolecular characterConformationScheme of a possible duplex formation between two HAchains. The two participating single HA helices areantiparallel to each other. The dotted lines delineate eachsugar unit, the circles represent acetamido, and squaresrepresent carboxylate groups. The gray dotted bars arethe hydrophobic patches stretching along three sugarunits on alternate sides of the polymer chains.On the basis of nuclear Overhauser enhancement (NOE)NMR combined with molecular modeling, they proposedthat the conformation of an octasaccharide of HA inaqueous solutions is defined by the torsion angles of theglycosidic linkages and by the orientation of the sidegroups φ 13 =46°and Ψ 13 =24°, which are the interglycosidicangles of the β 1-3 linkage, were obtained from restrainedmolecular dynamics calculations. For the β 1-4 linkage,two sets of values were consistent with the NOErestraints (φ 14 =24°and Ψ 14 =-53° or φ 1 =48°and Ψ 14 =8°).26