Insights on the conformational properties of hyaluronic acid by using NMR residual dipolar couplings and MD simulations.
The conformational features of hyaluronic acid, a key polysaccharide with important biological properties, have been determined through the combined used of nuclear magnetic resonance (NMR) spectroscopy and molecular modeling techniques. A decasaccharide fragment of sodium hyaluronate (HA) was submitted to 3.5 ns of molecular dynamics in explicit water environment form. The same decasaccharide was prepared by hyaluronidase digestion for the experimental study. The approach consisted in the measurements of NMR residual dipolar coupling (RDC) which were used to filter the molecular dynamics data by retaining those structures which were in agreement with the experimental observations. Further analysis of the new conformer ensemble (HA(RDC)) and clustering the molecules with respect to their overall length led to seven representative structures, which were described in terms of their secondary motifs, namely the best fitting helix geometry. As a result, this protocol permitted the assessment that hyaluronic acid can adopt two different arrangements, which can be described by a three- or four-folded left-handed helix, with a higher occurrence of the first one.
Gargiulo
Valentina
V
Department of Organic Chemistry and Biochemistry, University of Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, Naples, Italy.
Morando
Maria A
MA
Silipo
Alba
A
Nurisso
Alessandra
A
Pérez
Serge
S
Imberty
Anne
A
Cañada
F Javier
FJ
Parrilli
Michelangelo
M
Jiménez-Barbero
Jesús
J
De Castro
Cristina
C
D000276:Adjuvants, Immunologic / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D006820:Hyaluronic Acid / Q000737:chemistry*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular
D000276:Adjuvants, Immunologic; D006820:Hyaluronic Acid