1H-31P CPMG-Correlated Experiments for the Assignment of Nucleic Acids
B. Luy, John Marino
Phosphorus (31P) nuclear magnetic resonance (NMR) spectroscopy can provide important information about the structure and dynamics of nucleic acids in solution. The application of 31P NMR, however, often requires the difficult task of resolving and assigning individual 31P resonances. In this communication, a 1H-31P heteronuclear single quantum correlation (HSQC) NMR experiment for phosphorus resonance assignment is described that efficiently correlates phosphorus nuclei with scalar coupled sugar protons in both the 5' and 3' direction of a phosphodiester linkage. The effectiveness of the 1H-31P HSQC experiment results from the application of a train of closely spaced 180 pulses, or so called Carr-Purcell-Meiboom-Gill (CPMG) pulse train, during the periods of magnetization transfer between phosphorus and scalar coupled proton nuclei. The HP-CPMG-HSQC experiment is approximately 2.5-fold more sensitive than current standard phosphorus-proton correlation methods, which employ phosphorus excitation, and exhibits more favorable phosphorus-proton magnetization transfer properties with respect to heteronuclear Total Correlation Spectroscopy (heteroTOCSY) methods. Applied in combination with an NOE mixing period (HP-CPMG-HSQC-NOESY), the HP-CPMG-HSQC pulse sequence element yields both a significant improvement in sensitivity and an additional sequential assignment pathway between phosphorus and H1' proton resonances in oligonucleotides.
Journal of the American Chemical Society
<sup>31</sup>P, HETCOR, CMPG, HSQC, RNA
and Marino, J.
<sup>1</sup>H-<sup>31</sup>P CPMG-Correlated Experiments for the Assignment of Nucleic Acids, Journal of the American Chemical Society
(Accessed December 8, 2023)