th  - 1987 - 51st ENC Conference

WF50
Solid State NMR Dynamics Studies of Duplex RNA
Pearl Tsang*, Robert L. Void and Regitze R. Void
Department of Chemistry B-014
University of California at San Diego
La Jolla, CA. 92093
The results of dynamic studies of duplex RNA, obtained through a combination of
solid state H-2 and P-31 NMR techniques, are presented in this poster. The base pair and
phosphodiester backbone motions of duplexes at various relative humidities have been
separately examined using deuterium NMR to study purine-8 deuterated sites and phos-
phorous NMR to study the phosphodiester backbone, respectively. Deuterium spin-lattice
relaxation rates of RNA are determined both at 38.4 and 76.8 MHz. P-31 NMR lineshape
studies of RNA duplexes are also conducted.
Deuterium spin-lattice relaxation rates for the various purine-8 sites of the RNA du-
plexes studied show a trend of steadily decreasing T1 with increasing relative humidity.
Based upon the field dependence of the RNA T1 values, it appears that collective torsional
modes may be a dominant factor in the relaxation process.
The results obtained for RNA are briefly compared to those obtained from analo-
gous DNA samples. Significant dynamic differences between DNA and RNA have been
observed, based upon the rather different spin-lattice relaxation rates obtained for the two
species. P-31 NMR results for the RNA are also compared to those of the DNA.