MM3 Modeling of Ribose and 2-Deoxyribose Ring Puckering

Abstract

ABSTRACT Conformational energy maps for furanosyl and pyranosyl rings of α- and β-ribose and 2-deoxyribose were generated with the molecular mechanics program MM3. For the furanosyl tautomers, low-energy Northern and Southern minima were found. For the pyranosyl rings, lowest-energy minima corresponded to chair forms. Hydrogen-hydrogen coupling constants for the minimal-energy conformers were calculated based on Karplus equations. Computational and experimental results indicate that several tautomeric forms of ribose and 2-deoxyribose exist in multiple conformations in solution. Ring conformations of related crystal structures have energies within ∼2 kcal/mol of the calculated global minima.