High-Resolution Phosphorus Nuclear Magnetic Resonance Spectra of Yeast Phenylalanine Transfer Ribonucleic Acid. Metal Ion Effects and Tentative Partial Assignment of Signals

The temperature and metal ion dependence of the ³¹P NMR spectra of yeast phenylalanine tRNA is presented, and a tentative assignment of some of the individual phosphate signals is offered. Signals A, C, F, P, and T have been assigned to the magnesium binding site phosphates by monitoring the magnesium ion dependence in the ³¹P NMR spectra. In the presence of 10 mM Mg²⁺, specific paramagnetic line broadening effects are observed for signals A, D, E, and U upon addition of 0.001-0.1 Mn²⁺ ion per tRNA molecule. Through the combination of the above metal ion experiments, X-ray studies, and earlier ¹H and ³¹P NMR studies [particularly the tRNA modification ³¹P NMR experiments of Salemink et al. [Salemink, P. J. M., Swarthof, T., & Hilbers, C. W. (1979) Biochemistry 18, 3477]], an initial assignment of some of these signals is attempted.