Sequential resonance assignments in proton NMR spectra of oligonucleotides by two-dimensional NMR spectroscopy

Abstract

A sequential assignment procedure is outlined, based on 2-dimensional NOE [nuclear Overhauser effect] (NOESY) and 2-dimensional J-correlated spectroscopy (COSY), for assigning the nonexchangeable proton resonances in NMR spectra of oligonucleotides. As presented here the method is generally applicable to right-handed helical oligonucleotides of intermediate size. It was applied to a lac operator DNA fragment consisting of d(TGAGCGG) and d(CCGCTCA) and complete assignments were obtained for the adenine H8, guanine H8, cytosine H6 and H5, thymine H6 and 5-methyl, and the deoxyribose H1'', H2'', H2", H3'' and H4'' resonances, as well as some H5'', H5" (pairwise) assignments. These assignments are required for the analysis of 2-dimensional NOE and J-coupling data in terms of the solution structure of oligonucleotides.