Conformation of the exocyclic 5′-CH 2OH in nucleosides and nucleotides in aqueous solution from specific assignments of the H 5′, and H 5″ signals in the NMR spectra

Abstract

Analyses of published NMR spectra for uridine, β-pseudouridine and their 3′-monophosphates, together with the deshielding effect of a phosphate group, have made possible specific assignments of the signals of the two 5′ protons. This permits of a more accurate evaluation of the relative populations of the three CH 2OH conformers and, in turn, of a suitable choice of the constants in the Karplus relation applicable to this type of system. The results have been extended to a variety of other nucleosides and nucleotides, and to a consideration of the nature of the deshielding effect of a phosphate group on the ribose protons.