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United States Department of Agriculture

Agricultural Research Service

Title: Dft Studies of Hydrated Carbohydrates: Dft Molecular Dynamics Simulations at the B3lyp/6-31+g* Level of Theory

Authors
item Momany, Frank
item Schnupf, Udo
item Willett, Julious
item Bosma, Wayne - BRADLEY UNIV/CHEM DEPT

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2007
Publication Date: August 23, 2007
Citation: Momany, F.A., Schnupf, U., Willett, J.L., Bosma, W. 2007. DFT STUDIES OF HYDRATED CARBOHYDRATES: DFT MOLECULAR DYNAMICS SIMULATIONS AT THE B3LYP/6-31+G* LEVEL OF THEORY. Meeting Abstract. xx.

Technical Abstract: Several mono- and disaccharides have been studied by performing constant energy molecular dynamics at the B3LYP/6-31+G* + COSMO (solvation) level of theory, alpha-maltose is of particular interest as the variation in glycosidic dihedral angles is dependent upon the starting hydroxyl conformation. That is, when the simulation is started from the all "c" or all "r" form, convergence toward the other form occurs as the molecules become equilibrated. Of interest is that the "r" conformation with COSMO is of lower starting energy (less than 1 kcal/mol) than the "c" form starting energy, in contrast to the vacuum optimized structures which have very similar relative energies. The H1---H4' distance across the glycosidic bond remains at less than 2.15A during the dynamics for both forms. This result is in excellent agreement with recent NMR studies. Other DFT dynamics simulations on mono-saccharides, including the COSMO solvation term, produced results with fairly reliable alpha/Beta anomeric ratios and hydroxymethyl rotamer populations in good agreement with experimental studies.

Last Modified: 9/23/2014
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