14] 31P NMR of DNA

Abstract

Publisher Summary With the tremendous increase in sensitivity and pulse sequence capabilities in modern Fourier-transform nuclear magnetic resonance (FT NMR) spectrometers, 31 P NMR spectroscopy of nucleic acids grew dramatically during the 1980s. This chapter describes methods for obtaining one- and two-dimensional 31 P NMR spectra of DNA as well as the interpretation of 31 P chemical shifts and coupling constants and their application to nucleic acid structure. 31 P NMR has developed as a powerful probe of the structure and dynamics of DNA and DNA fragments in solution. The concomitant development of sequence-specific two-dimensional 1 H/ 1 H and 1 H/ 31 P NMR assignment methodologies and higher-field spectrometers has made the study of the 31 P NMR spectrum of modest size oligonucleotides possible. One of the main reasons for assigning 31 P resonances of oligonucleotides is to obtain information on the conformation of the phosphodiester backbone. The internucleotide linkage is defined by six torsional angles from one phosphate atom to the next along the DNA backbone. Theoretical studies have shown that the conformations of two of the six torsional angles appear to be most important in determining 31 P chemical shifts.