Sensitivity of Polar Solvation Dynamics to the Secondary Structures of Aqueous Proteins and the Role of Surface Exposure of the Probe

Bandyopadhyay, Sanjoy and Chakraborty, Sudip and Balasubramanian, Sundaram and Bagchi, Biman (2005) Sensitivity of Polar Solvation Dynamics to the Secondary Structures of Aqueous Proteins and the Role of Surface Exposure of the Probe. In: Journal of the American Chemical Society, 127 (11). pp. 4071-4075.

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Abstract

The structure and dynamics of water around a protein is expected to be sensitive to the details of the adjacent secondary structure of the protein. In this article, we explore this sensitivity by calculating both the orientational dynamics of the surface water molecules and the equilibrium solvation time correlation function of the polar amino acid residues in each of the three helical segments of the protein HP-36, using atomistic molecular dynamics simulations. The solvation dynamics of polar amino acid residues in helix-2 is found to be faster than that of the other two helices (the average time constant is smaller by a factor of 2), although the interfacial water molecules around helix-2 exhibit much slower orientational dynamics than that around the other two helices. A careful analysis shows that the origin of such a counterintuitive behavior lies in the dependence of the solvation time correlation function on the surface exposure of the probe-the more exposed is the probe, the faster the solvation dynamics. We discuss that these results are useful in explaining recent solvation dynamics experiments.

Item Type:	Journal Article
Publication:	Journal of the American Chemical Society
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	16 May 2005
Last Modified:	25 Jan 2012 08:29
URI:	http://eprints.iisc.ac.in/id/eprint/3100

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