Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 3: Computational Biophysics (joint BP/DY)

DY 3.7: Talk

Monday, March 20, 2017, 11:30–11:45, ZEU 250

Organic co-solutes in aqueous solution: The effect on local water dynamics — Johannes Zeman, Frank Uhlig, and •Jens Smiatek — Institut für Computerphysik, Universität Stuttgart, D-70569 Stuttgart, Germany

We investigate the effect of the organic co-solutes ectoine, trimethylamine N-oxide (TMAO), urea, and guanidinium chloride by means of classical and ab-initio Molecular Dynamics simulations. Our results reveal distinct effects on the local water structure and the water dynamics for the different co-solutes. The analysis of the diffusion coefficients and the dielectric spectra demonstrate that ectoine and TMAO significantly slow down water dynamics by a strongly bound hydration shell whereas urea and guanidinium chloride have a weaker impact. In combination with a sodium chloride solution, our findings for ectoine imply compensatory effects in order to explain the high co-solute and salt concentration in halotolerant bacteriae [1].

[1] M. B. Hahn, F. Uhlig, T. Solomun, J. Smiatek, H. Sturm; Phys. Chem. Chem. Phys. 18, 28398 (2016)