Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 28, 2003
Publication Date: June 12, 2003
Citation: MOMANY, F.A., APPELL, M.D., WILLETT, J.L. B3LYP/6-311++G** STUDIES ON HYDRATES OF CARBOHYDRATES:EFFECT OF EXPLICIT WATER MOLECULES ON THE CONFORMATION AND ENERGIES OF SELECTED MONO- AND DI-SACCHARIDES.. MEETING ABSTRACT. 2003. Abstract p. 80. Technical Abstract: Geometry/energy optimzation of cellobiose hydrates, and mono-, penta-, deca-hydrates of glucose were carried out at the B3LYP/6-311++G** level of theory. Energetically favored hydration sites were found and the molecular stress energies associated with the interaction of the water molecules obtained. Enthalpy, entropy, zero point energy, and hydrogen bond energies are reported. Twenty one mono-, fourteen penta- and six deca-hydrates of glucose were examined and favored patterns for the water configurations established. Networks of hydrogen bonding are observed, and the occupation numbers for water hydrogen bonding examined. A new shorthand algorithm is described to help distinguish the positions of the water molecules around the carbohydrate molecule. Previous calculations on B-D-cellobiose and some cellobiose analogs showed that the most energetically stable conformation was one where the dihedral angel phi was "flipped" by 180 degrees relative to the "normal" or observed form. To understand the above observation, cellobiose hydrates were studied. Preliminary studies of several cellobiose mono-hydrates suggested that more than one water molecule is required for the "normal" conformation of the hydrate to be energetically preferred.