Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2005
Publication Date: June 22, 2005
Citation: Bosma, W., Appell, M.D., Willett, J.L., Momany, F.A. 2005. Stepwise hydration of a disaccharide: DFT calculations of structural and energetic changes as 1 to 4 water molecules are added to b-cellobiose [abstract]. American Chemical Society. Paper No.94. Technical Abstract: Recent theoretical and experimental evidence has shown that a stable form of the isolated cellobiose molecule is a conformer "flipped" by 180 deg about the glycosidic linkage compared to the "normal" conformer found in a solution and in the crystalline form. DFT calculations at the B3LYP/6-311++G** level of theory have been performed on cellobiose-water complexes to determine the origins of this stability. Changes in electronic energy and in internal coordinates will be described as 1 to 4 water molecules are placed in various hydrogen-bonding sites around the cellobiose molecule. The relative energies between conformers change dramatically as water molecules are placed around the molecule, with 2 water molecules being sufficient to bring the "flipped" and "normal" conformers to approximately the same electronic energy. The most significant interactions of water with cellobiose occur at sites between the rings, where there is an enhancement of the cross-ring interactions in the "normal" conformers and a disruption of the synergistic hydrogen bonding network in the "flipped" conformers.