Stereoselective nucleoside deuteration for NMR studies of DNA.

A procedure has been elaborated for stereoselective deuterium substitution of one of the diastereotopic 5'-protons in 2'-deoxynucleotides. The synthetic scheme uses the reduction of the 5-oxosugar derivative with deuterated Alpine-Borane. The resulting deuterosugar is converted into pyrimidine nucleosides and incorporated into DNA using standard protocols. Comparison of two-dimensional NMR spectra of the fully protonated and partially deuterated duplexes allowed us to assign diastereotopic 5' protons, increasing the number of experimental restraints used for structure determination.