Molecular structure of hyaluronan: an introduction

Abstract

Hyaluronan is an unbranched polysaccharide of repeating disaccharides consisting of D-glucuronic acid and N-acetyl-D-glucosamine. Its strong water-retaining ability and visco-elastic properties have been broadly utilized in medical applications. Hyaluronan is an important constituent of the extracellular matrix whose physiological functions are manifested both as the substance is by itself as well as when it is being linked to various proteins. Compared with other biopolymers, such as nucleic acids and proteins, the structural chemistry of hyaluronan is much less developed. The scarce information about the metrical aspects of its structure shows no unusual features. Its secondary structure is characterized by intramolecular hydrogen bonding that is hard to distinguish from hydrogen bonding involving water molecules when hyaluronan is in aqueous medium. The tertiary structure of hyaluronan is sensitively dependent on its environment. The relative rigidity of the glycosidic bond and the intramolecular hydrogen bonds would tend to restrict rotational freedom and thus conformational variability. This, however, seems to be overwritten by the impact of molecular environment leading to a great variability of tertiary structure. A large number of conformations are possible and may be present as witnessed by their rather small free energy differences.Of the plethora of physical techniques and computational methods, X-ray crystallography and molecular dynamics calculations have proved to be the most fruitful so far. There are untapped possibilities in NMR spectroscopy for structural studies and quantum chemical calculations are also expected to contribute substantially to the structural chemistry of hyaluronan. There are many basic data as well as structural intricacies of hyaluronan that have so far eluded the researchers of its molecular structure.

Molecular structure of basic oligomeric building units of heparan-sulfate glycosaminoglycans

“…Hricovíni et al examined structure and spin-spin coupling constants of monomeric and dimeric units of glucosaminoglycans [22][23][24]. Molecular structure of structurally related hyaluronan was recently reviewed [25], and conformational properties of the disaccharide-building units of hyaluronan were investigated using the density functional theory (DFT) [26]. Some of novel anticoagulants were also treated theoretically [27].…”

Hyaluronsäuregele zur Druckregulierung in der Glaukomtherapie

“…Damit können schon bei niedrigen Konzentrationen hochviskose und elastische Lösungen entstehen. Diese Eigenschaftensowie die gute Biokompatibilität haben dazu geführt, dass HA bereits in vielen Bereichen der Medizin wie der Orthopädie,derSchönheitschirurgie,der Wundheilung und auch der Ophthalmologie zum Einsatz kommt [1,7,9,10,26]. Chemisch modifizierte HA wird z.…”

Crystallography in Structural Chemistry

“…His review covered a broad range of structural studies on a variety of polysaccharides involving various experimental techniques as well as molecular modeling and computer simulations. Scott's studies served as one of the inspirations for us to look more into the structural intricacies of a particular polysaccharide, hyaluronic acid, called also hyaluronan [37]. Lately, this substance has gained great visibility and fame for its presence in relatively great concentrations in some specific areas of the human body (such as, for example, the vitreous, the umbilical cord, the joints, and in the skin); for its most efficient clinical use; and for its popularity as an anti-aging agent in cosmetics.…”