OPLS all-atom force field for carbohydrates

✍ Scribed by Damm, Wolfgang; Frontera, Antonio; Tirado-Rives, Julian; Jorgensen, William L.

• Book ID: 101220685
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 404 KB
• Volume: 18
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/(sici)1096-987x(199712)18:16<1955::aid-jcc1>3.0.co;2-l

✦ Synopsis

The OPLS all-atom AA force field for organic and biomolecular systems has been expanded to include carbohydrates. Starting with reported nonbonded parameters of alcohols, ethers, and diols, torsional parameters were fit to reproduce results from ab initio calculations on the hexopyranoses, ␣,␤-Dglucopyranose, ␣,␤-D-mannopyranose, ␣,␤-D-galactopyranose, methyl ␣,␤-Dglucopyranoside, and methyl ␣,␤-D-mannopyranoside. In all, geometry optimizations were carried out for 144 conformers at the restricted Hartree᎐Fock Ž .

U RHF r6᎐31G level. For the conformers with a relative energy within 3 kcalrmol of the global minima, the effects of electron correlation and basis-set extension were considered by performing single-point calculations with density functional theory at the B3LYPr6᎐311 q G UU level. The torsional parameters for the OPLS-AA force field were parameterized to reproduce the energies and structures of these 44 conformers. The resultant force field reproduces the ab initio calculated energies with an average unsigned error of 0.41 kcalrmol. The ␣r␤ ratios as well as the relative energies between the isomeric hexopyranoses are in good accord with the ab initio results. The predictive abilities of the force field were also tested against RHFr6᎐31G U results for D-allopyranose with excellent success; a surprising discovery is that the lowest energy conformer of D-allopyranose is a ␤ anomer.