# Anisotropic and sub-diffusive water motion at the surface of DNA and of an anionic micelle CsPFO

Pal, Subrata and Maiti, Prabal K and Bagchi, Biman (2005) Anisotropic and sub-diffusive water motion at the surface of DNA and of an anionic micelle CsPFO. In: Journal of Physics: Condensed Matter, 17 (49). S4317-S4331.

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## Abstract

We use long atomistic molecular dynamics simulations to address certain fundamental issues regarding water dynamics in the hydration layer of a 38 base long (GCCGCGAGGTGTCAGGGATTGCAGCCAGCATCTCGTCG) negatively charged hydrated DNA duplex. The rotational time correlation function of surface water dipoles is found to be markedly non-exponential, with a slow component at long time, whose magnitude depends on the initial (t = 0) residence of the water in the major or minor groove of the DNA. The surface water molecules are also found to exhibit anisotropic diffusion in both the major and minor grooves: diffusion in the direction parallel to the DNA surface exhibits a crossover from higher to lower than that in the direction normal to the surface at short-to-intermediate times. In the same time window, translational motion of water molecules in the minor groove is subdiffusive, with mean square displacement (MSD) growing as $t^{\alpha}$ with $\alpha \simeq 0.43$. In general, water molecules in the major group exhibit faster dynamics than those in the minor groove, in agreement with earlier results (Bonvin et al 1998 J. Mol. Biol. 282 859–73). We compare these results with dynamics of watermolecules at the surface of an anionicmicelle, cesiumperfluorooctanoate(CsPFO). Watermolecules on the surface ofCsPFOalso exhibit slowtranslation and non-exponential orientational dynamics.

Item Type: Journal Article The Copyright belongs to IOP Publishing Ltd. Division of Chemical Sciences > Solid State & Structural Chemistry UnitDivision of Physical & Mathematical Sciences > Physics 03 Apr 2006 19 Sep 2010 04:25 http://eprints.iisc.ernet.in/id/eprint/6159