ARS | Publication request: DFT studies of the hydrated carbohydrate, glucose: optimization and DFTMD simulations of ten explicit waters superimposed with an implicit solvation method, COSMO

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 2, 2011
Publication Date: June 10, 2011
Citation: Momany, F.A., Udo, S. 2011. DFT studies of the hydrated carbohydrate, glucose: optimization and DFTMD simulations of ten explicit waters superimposed with an implicit solvation method, COSMO. Meeting Abstract.

Technical Abstract: One of the most important and least understood properties of carbohydrates is their conformational profile in solution. The study of carbohydrates in solution is a most difficult computational problem, a result of the many soft conformational variables (hydroxyl groups) inherent in the structures of sugars. DFT calculations are described using a reduced basis set, B3LYP/6-31+G*/4-31G on carbons, plus ten water molecules, plus an implicit solvent method, COSMO, superimposed on the hydrated sugar. One question we wish to address is: are explicit water molecules necessary to understand solution structures, or can an implicit model correctly simulate the conformational profile of glucose in solution? We attempt to answer this using optimization methods on the 10 water + glucose complex to find low energy configurations of the water molecules, followed by DFTMD (molecular dynamics) simulations over 5, 10, or 30 ps. Numerous glucose conformations with explicit waters were studied and results expressed in residence position and time suggest considerable motion takes place with water molecules moving rapidly around and off of the sugar. By introducing COSMO we assure that no matter the positions of the waters, a hydrated state exists around all the molecules.