The systematic influence of solvent on the conformational features of furanosides.

The endo- and exo-anomeric effects are the two most recognizable stereoelectronic effects exhibited by carbohydrates. Their presence relies on the interactions between ring substituent(s) and ring oxygen atoms. Here, we report the finding of a new effect that partially controls the conformational properties of furanose rings and can be ascribed to the influence of the solvent on the electronic structure of a molecule.

Tautomeric and epimeric equilibria of aldo- and ketohexoses studied by the MD simulations and QM calculations.

The article is devoted to the problem of molecular modeling of tautomeric and epimeric equilibria in aqueous solutions of unfunctionalized d-aldo- and d-ketohexoses. We have applied the computational protocol proposed in our previous article [Gaweda, Plazinski, Phys. Chem.

A GROMOS Force Field for Furanose-Based Carbohydrates.

The article describes a GROMOS force field parameter set for molecular dynamics simulations of furanose carbohydrates. The proposed united-atom force field is designed and validated with respect to the conformational properties of furanose mono-, di-, oligo-, and polymers in aqueous solvent. The set accounts for the possibility of arbitrary glycosidic linkage connectivity between units, O-alkylation, as well as of different anomery.

Extension of the GROMOS 56a6 Force Field for Charged, Protonated, and Esterified Uronates.

An extension of the GROMOS 56a6 force field for hexopyranose-based carbohydrates is presented. The additional parameters describe the conformational properties of uronate residues. The three distinct chemical states of the carboxyl group are considered: deprotonated (negatively charged), protonated (neutral), and esterified (neutral).

Pyranose ring conformations in mono- and oligosaccharides: a combined MD and DFT approach.

Among the descriptors of the molecular structure of carbohydrates, the conformation of the pyranose ring is usually the most problematic one to tackle. We present the results of a systematic study oriented at determining the ring-inversion properties of all d-hexopyranoses in the form of monosaccharides, O-methylated monosaccharides and homotrisaccharides. Contrary to the existing studies, based either on molecular mechanics force fields or on conformational search within ab initio potentials, we combine the structural information from molecular dynamics simulations performed within the GROMOS 56a6 force field and use it in a subsequent geometry optimization procedure, performed at the DFT level of theory.