Chemically induced dynamic nuclear polarization studies of yeast tRNA/sup Phe/
Chemically induced dynamic nuclear polarization (CIDNP) has been observed from yeast tRNA/sup Phe/ following reaction with photoexcited riboflavin. At 20/sup 0/C, several resonances of tRNA in the native form show polarization; previous work predicts that only guanosine and its derivatives in single-stranded regions are likely to become polarized. The methyl protons of m/sub 2//sup 2/G-26 show strong negative spin polarization, indicating that this residue is accessible. The solvent accessibility of this residue has not been previously demonstrated. In addition, two positively polarized aromatic resonances are observed, which are likely due to two or more G(H8) protons, including those of G-20, m/sub 2//sup 2/G-26, and/or Gm-34. For temperatures below 50/sup 0/C, a negatively polarized signal in the aromatic region is shown to arise from cross relaxation with the methyl group protons of m/sub 2//sup 2/G-26. This indicates the proximity of an aromatic proton, probably H2 of A-44, to the methyl groups of m/sub 2//sup 2/G-26. At higher temperatures, the CIDNP spectra show polarization of several additional G resonances, including those of m/sup 2/G-10. These changes in the CIDNP spectra reflect melting of the tertiary and secondary structure of the tRNA. This work is the first use of CIDNP to study a large nucleic acid molecule and exemplifies the value of this technique in probing single-stranded and solvent-accessible regions of tRNA.
- Research Organization:
- Stanford Univ., CA
- DOE Contract Number:
- AT03-82ER60090
- OSTI ID:
- 5906513
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 23:9; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
550700 -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
FUNGI
MAGNETIC RESONANCE
MICROORGANISMS
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEIC ACIDS
NUCLEOTIDES
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
POLARIZATION
RESONANCE
RIBOFLAVIN
RNA
SPECTRA
TEMPERATURE DEPENDENCE
TRANSFER RNA
VITAMIN B GROUP
VITAMINS
YEASTS