Hyaluronan: The Local Solution Conformation Determined by NMR and Computer Modeling is Close to a Contracted Left-handed 4-Fold Helix

Andrew Almond, Paul L. DeAngelis, Charles D. Blundell

    Research output: Contribution to journalArticlepeer-review


    The polysaccharide hyaluronan (HA) is a ubiquitous component of the vertebrate extracellular matrix with diverse physiological roles from space-filling to acting as a scaffold for other macromolecules. The molecular interactions responsible for these solution properties have been the subject of much debate and, primarily due to the lack of residue-specific experimental data, no consensus model for the three-dimensional conformation nor dynamics of HA in solution has emerged. Here, the solution conformation of HA is investigated using molecular dynamics (MD) simulations and high-field nuclear magnetic resonance (NMR). In contrast to previous studies, MD simulations incorporated explicit water molecules and sodium ions, while NMR experiments utilized 15N-enriched oligosaccharides to allow residue-specific information to be obtained. The resultant average conformation (PDB code 2BVK) is predicted to be almost a contracted left-handed 4-fold helix; i.e. similar to that observed for sodium hyaluronate fibers by X-ray diffraction, but with the acetamido side-chain trans to H2. The glycosidic linkages and acetamido side-chains are predicted to have standard deviation rotations of 13° and 18° around their mean conformations in free solution, respectively, and are not observed to be stabilized by strong intramolecular hydrogen bonds as X-ray fiber diffraction refinements describe for the solid-state. Rather, weak and transient hydrogen bonds that are in rapid interchange with solvent molecules are predicted. These predictions are quantitatively consistent with demanding residue-specific NMR data and correspond to an HA molecule that is rod-like as an oligosaccharide and behaves as a stiffened random coil at large molecular mass, in close agreement with previous hydrodynamic observations. This new description of the solution conformation of HA is consistent with all available experimental data and accounts for its viscoelastic space-filling properties. This representation can be used as a basis for modeling the association between HA and proteins, which will elucidate important aspects of extracellular matrix assembly. © 2006 Elsevier Ltd. All rights reserved.
    Original languageEnglish
    Pages (from-to)1256-1269
    Number of pages13
    JournalJournal of molecular biology
    Issue number5
    Publication statusPublished - 19 May 2006


    • conformation
    • hydrogen bond
    • molecular dynamics
    • polysaccharide
    • water


    Dive into the research topics of 'Hyaluronan: The Local Solution Conformation Determined by NMR and Computer Modeling is Close to a Contracted Left-handed 4-Fold Helix'. Together they form a unique fingerprint.

    Cite this