Random coils and solvation shell of hyaluronan in electrolytes solutions

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28110%2F18%3A63520161" target="_blank" >RIV/70883521:28110/18:63520161 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Random coils and solvation shell of hyaluronan in electrolytes solutions

Original language description

Hyaluronic acid (HA, hyaluronan), an alternating co-polymer of glucuronic acid and N-acetylglucosamine ([4)-β-D-GlcpA-(13)-β-D-GlcpNAc-(1]n), is a major component of extracellular matrix of animal connective tissues with a variety of biological roles and technological application. In aqueous solution, HA molecules form random coils the size of which was studied experimentally many times and the dependence of the radius of gyration (Rg) on the identity and concentration of different salts in the solution was described. In general, the random coils shrink when the salt concentration increases. The aim of our work is to simulate the electrolyte effects on HA random coils by molecular dynamics and to describe the key phenomena driving the random coil formation. A HA oligosaccharide of 48 monosaccharide residues was simulated in appropriate solvent for 80 ns and, subsequently, large random coils were composed of its randomly selected fragments connected in accord with the statistics of the dihedral-angle couples of the glycosidic bonds between the residues. Rg was then determined from a statistically significant ensemble of the coils generated this way. The results show a good agreement with experiment regarding the both the absolute Rg value and its dependence on electrolyte concentration [1]. However, a similar behavior was observed also for a neutral HA analog containing glucose instead of glucuronic acid which indicates that the repulsion of the negative charges of the carboxylate groups are not the key factor determining the random-coil shape. Therefore, we analyze the structure of the solvation shell of both the polymers using a cumulative solvation-shell diagrams in which the surroundings of all residues of the same kind within several simulation frames is superimposed to one 2D plot. Using this and other analyses we identify the differences in the water structure of different polysaccharides, distributions of ions and variations in the molecular geometry. The results indicate that the random-coil shrink as a consequence of disturbing the solvation shells by weakly bound ions that increase the chain conformational entropy and thus induce the closer packing of the molecule.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10610 - Biophysics

Project

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Continuities

S - Specificky vyzkum na vysokych skolach

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů