Investigation of the Structure of Yeast tRNAPhe by Nuclear Magnetic Resonance: Paramagnetic Rare Earth Ion Probes of Structure

AUTOR(ES)

Jones, Claude R.

RESUMO

The binding of paramagnetic rare earth ions to yeast tRNAPhe shifts some resonances in the low-field nuclear magnetic resonance spectrum that have been assigned to ring nitrogen protons of specific Watson-Crick base pairs. The changes in the nuclear magnetic resonance spectrum as the tRNA is titrated with Eu3+ indicate that 4 (or 5) Eu3+ ions are tightly bound, that the metal binding is in the fast exchange limit, and that the binding to different sites in the molecule is sequential rather than cooperative. The first metal bound simultaneously shifts resonances associated with the dihydrouridine and the -C-C-A stem. This permits us to conclude that the folding of the tRNAPhe in solution brings the phosphate backbone of the -C-C-A and the dihydrouridine stems into close proximity. A model of the three-dimensional structure of tRNAPhe incorporating this new information appears to be compatible with the results obtained from x-ray diffraction.

Documentos Relacionados

• Nuclear magnetic resonance observation of the triple interaction between A9 and AU12 in yeast tRNAPhe.
• Nuclear magnetic resonance studies on yeast tRNAPhe. III. Assignments of the iminoproton resonances of the tertiary structure by means of nuclear Overhauser effect experiments at 500 MHz.
• Nuclear magnetic resonance studies on yeast tRNAPhe I. Assignment of the iminoproton resonances of the acceptor and D stem by means of Nuclear Overhauser Effect experiments at 500 MHz.
• Nuclear magnetic resonance studies on yeast tRNAPhe. II. Assignment of the iminoproton resonances of the anticodon and T stem by means of nuclear Overhauser effect experiments at 500 MHz.
• Hydrogen-bonded protons in the tertiary structure of yeast tRNAPhe in solution.