College of Liberal Arts & Sciences

Non-local electrostatic effects at the protein-solvent interface within macroscopic continuum model

Nov 23, Wed, 2005
9:00am - 10:00am, International Room, Kansas Union

Alexander Rubinstein

Eppley Institute for Research in Cancer and Allied Diseases and Department of Pharmaceutical Science, College of Pharmacy, University of Nebraska Medical Center, Omaha

 

The proper estimation of the influence of the dynamic solvent microstructure on a pair-wise electrostatic interaction (PEI) at the protein-solvent interface is very important for solving many biophysical problems. In this work, the PEI energy was calculated for a system that models the interface between a protein and an aqueous solvent. The concept of non-local electrostatics for interfacial electrochemical systems was used to evaluate the contribution of a solvent orientational (Debye) polarization, correlated by the network of hydrogen bonds, into the PEI energy in proteins. The analytical expression for this energy was obtained in the form of Coulomb’s law with an effective distance-dependent dielectric function. The asymptotic and numerical analysis carried out for this function revealed several features of dielectric heterogeneity at the protein-solvent interface. For charges located in close proximity to this interface, the values of the dielectric function for the short-distance electrostatic interactions were found to be remarkably smaller than those determined by the classical model, in which the solvent was considered as the uniform dielectric medium of high dielectric constant. Our results have shown that taking into consideration the dynamic solvent microstructure remarkably increases the value of the PEI energy at the protein–solvent interface.


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