Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: January 12, 2008
Publication Date: March 14, 2008
Citation: Schnupf, U., Willett, J.L., Bosma, W.B., Momany, F.A. 2008. A new era of carbohydrate modeling using cutting edge DFT methods. American Chemical Society Abstracts. xx. Technical Abstract: During the last several years we have seen vast improvements in the quality of carbohydrate simulations, including Density Functional Theory (DFT) structure determination and ab initio molecular dynamics studies of low energy conformers of mono-, di-, and larger saccharides at a level of theory that only ten years ago would have defied the computational resources available. Today, with access to very fast processors, it is possible to search for conformers of low energy, gradient optimize these structures, and compare energies, frequencies, geometries, and conformational maps with relatively modest resources available at reasonable cost. We have previously published, at the B3LYP/6-311++G** level of theory, conformational analysis papers of numerous glucose epimers, several disaccharides such as maltose and cellobiose, trisaccharides, and recently completed a study on tetrasaccharides. In addition, DFT molecular dynamics simulations were carried out for the epimers of glucose and maltose using a smaller 6-31+G* basis set with an implicit solvent model. Further, we have calculated isopotential and isogeometric maps for maltose at the B3LYP/6-31+G* level of theory. To extend our studies we have investigated the effect that solvent has on the energy and structure of carbohydrates. Today, we have exhaustive data on implicitly solvated (COSMO and PCM) small saccharides, and some explicit solvent results. From results noted above it is possible to compute a wide array of properties that can be compared with various computational and experimental studies. One major conclusion from our work on maltose is that it is not a particularly good model for larger amylose like polymers. A summary of the above studies will be presented.