13C Nuclear magnetic relaxation study of segmental dynamics of hyaluronan in aqueous solutions
| Autor: | John Kanetakis, Emmanuel Tylianakis, Francois R Taravel, Photis Dais |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Magnetic Resonance Spectroscopy
Polymers and Plastics Bioengineering 02 engineering and technology 010402 general chemistry Ring (chemistry) 01 natural sciences Biomaterials Nuclear magnetic resonance Materials Chemistry Molecule Hyaluronic Acid Protein secondary structure Carbon Isotopes Chemistry Hydrogen bond Relaxation (NMR) Water 021001 nanoscience & nanotechnology 0104 chemical sciences Solutions Amplitude Diffusion process Chemical physics Intramolecular force 0210 nano-technology |
| Zdroj: | Biomacromolecules. 6(3) |
| ISSN: | 1525-7797 |
| Popis: | (13)C spin-lattice relaxation times (T(1)) and nuclear Overhauser enhancements (NOE) were measured as a function of temperature and magnetic field strength for the hetero-polysaccharide hyaluronan in water solutions. The relaxation data of the endocyclic ring carbons were successfully interpreted in terms of chain segmental motions by using the bimodal time-correlation function of Dejean de la Batie, Laupretre and Monnerie. On the basis of the calculated correlation times for segmental motion and amplitudes of librational motions of the C-H vectors at the various carbon sites of the HA repeating unit, we concluded that intramolecular hydrogen bonding of the secondary structure of HA plays a major role in the conformational flexibility of this carbohydrate molecule. The internal rotation of the free hydroxymethyl groups about the exocyclic C-5-C-6 bonds superimposed on segmental motion has been described as a diffusion process of restricted amplitude. The rate and amplitude of the internal rotation indicate that the hydroxymethyl groups are not involved in intramolecular hydrogen bonding. Finally, the motional parameters describing the local dynamics of the HA chain were correlated with the secondary structure of HA in aqueous solutions. |
| Databáze: | OpenAIRE |
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