Hyaluronan random coils in electrolyte solutions—a molecular dynamics study

Abstract

A computational method of modeling random coils of hyaluronan was developed based on the molecular-dynamics simulations. An oligosaccharide of 48 monosaccharide units was equilibrated within a 70-100ns simulation and randomly chosen pieces of this molecule from different simulation frames were combined to constitute a long polysaccharide chain, both for hyaluronan and its non-ionic analog containing glucose instead of glucuronic acid. The dihedral angles of the glycoside connections of the pieces obeyed the statistics deduced from the simulation. The simulations were performed at various concentrations of NaCl and MgCl. The calculated radii of gyration show a striking agreement with experimental data from the literature and indicate a key importance of the polymer-ion interactions for the random-coil conformation, but a low influence of the excluded volume of the chain and the carboxylate-groups repulsion. The method has thus the potential to become a versatile tool of modeling macromolecules of various semirigid polymers.

Effect of solvent and ions on the structure and dynamics of a hyaluronan molecule

“…S4, which indicates that the widths of the major peaks are practically independent of the temperature and salt concentration. When an ensemble of random coils of a certain number of monosaccharide units is generated combining individual residues with the dihedral angles of their glycosidic connection obeying the distribution given solely by the major peaks, the radius of gyration is in a good agreement with the values for the salt-free solution of HA from our previous calculation (Ingr et al, 2017) as well as the experiment (Fig. S3).…”

“…In our previous work we presented a method of calculating the random-coil size from a simulation of a short oligosaccharide (Ingr, Kutálková, & Hrnčiřík, 2017). The values of the radius of gyration obtained this way agreed well with experiment for a wide range of HA molecular weight and for several different values of the salt concentration in the solution.…”

“…3.1. End-to-end distance and persistence length of the HA chain Previously (Ingr et al, 2017), we proposed a method for calculating the radii of gyration of HA composing a long random coil from fragments of a short oligosaccharide. In that calculation the dihedral angles of the glycosidic connections were inherently present in the chain fragments.…”

Electrospinning of Hyaluronan Using Polymer Coelectrospinning and Intermediate Solvent

“…Its primary structure is linear, and its secondary structure is typically a twisted ribbon. Due to a rather stiff backbone chain caused by the disaccharide structure, internal hydrogen bonds, and interactions with solvents, the ternary structure is an expanded random coil [23,24]. It was experimentally proven that the presence of ions can influence coil diameter [25].…”

Investigation of a polyelectrolyte degradation with viscometry

“…Barrat, Joanny and Dobrynin stated that the electrostatic persistence length of charged flexible chains scales on the order of the Debye screening length. [6][7][8][9][10] Polydiallyl dimethylammonium chloride (PDADMAC) is a cationic polymer, which has a backbone of cyclic units including a cationic quaternary ammonium structure within every chain that gives the polymer a better solubility comparable to that of strong PEs. PDADMAC polymers have been preferred for numerous industrial applications.…”