Determination of the DNA sugar pucker using carbon-13 NMR spectroscopy

Publisher Website
Google Scholar
Abstract
Solid-state 13C NMR spectroscopy of a series of crystalline nucleosides and nucleotides allows direct measurement of the effect of the deoxyribose ring conformation on the carbon chemical shift. It is found that 3'' and 5''-endo conformers have 3'' and 5'' chemical shifts significantly (5-10 ppm) upfield of comparable 3''-exo and 2''-endo conformers. The latter two conformers may be distinguished by smaller but still significant differences in the carbon chemical shifts at the C-2'' and C-4'' positions. High-resolution solid-state NMR of three modifications of fibrous calf thymus DNA shows that these trends are maintained in high-molecular-weight DNA and confirms that the major ring pucker in A-DNA is 3''-endo, while both B-DNA and C-DNA are largely 2''-endo. The data show that 13C NMR spectroscopy is a straightforward and useful probe of DNA ring pucker in both solution and the solid state.