/sup 19/F NMR studies of 5-fluorouracil-substituted Escherichia coli transfer RNAs: solution structure and codon-anticodon interaction
/sup 19/F NMR was used to study E. coli tRNA/sub 1//sup Val/, tRNA/sub f//sup Met/, and tRNA/sub m//Met/, in which 5-fluorouracil (FUra) has replaced uracil and uracil-derived minor bases. /sup 19/F NMR spectra of these tRNAs resolve resonances from nearly all the incorporated FUra residues. Each of the three tRNAs can be resolved into two isoaccepting species, termed forms A and B, whose /sup 19/F spectra differ in the shift of one /sup 19/F peak from ca. 4.5 ppm in form B, upfield to -15 ppm in form A. Because the two isoacceptors of each tRNA differ only at one position, the peaks at 4.5 ppm in the spectra of (FUra)tRNA/sub 1//sup Val/ and (FUra)tRNA/sub m//sup Met/; are assigned to FUra 17 and Fura 20 respectively. Bisulfate modification and pH dependence indicate that /sup 19/F signals in the central region of the spectrum of (FUra)tRNA/sub 1//sup Val/ correspond to fluorouracils in non-base-paired regions. Photoreaction with psoralen indicates upfield /sup 19/F signals arise from residues in helical environments. Removal of magnesium or addition of NaCl produces major, reversible changes in the /sup 19/F spectrum of fluorinated tRNAs. Studies of manganese and spermine binding to (FUra)tRNA/sub 1//sup Val/ allow localization of several resonances in the /sup 18/F spectrum to regions near putative binding sites for these ions. Binding of the codon G/sub p/U/sub p/A causes an upfield shift of a /sup 19/F resonance at 3.9 ppm in the spectrum of (FUra)tRNA/sub 1//sup Val/. G/sub p/U/sub p/A/sub p/A, which is complementary to the anticodon and 5'-adjacent FUra 33, shifts an additional /sup 19/F peak at 4.5 ppm. /sup 1/H NMR and RNase H digestion studies show that the oligonucleotides bind to the anticodon.
- Research Organization:
- Iowa State Univ. of Science and Technology, Ames (USA)
- OSTI ID:
- 6710917
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ESCHERICHIA COLI
BIOCHEMISTRY
TRANSFER RNA
NUCLEAR MAGNETIC RESONANCE
CODONS
FLUORINE 19
FLUOROURACILS
METHIONINE
NMR SPECTRA
NUCLEOTIDES
PH VALUE
PSORALEN
SULFATES
VALINE
AMINO ACIDS
ANTICOAGULANTS
ANTIMETABOLITES
AZINES
BACTERIA
CARBOXYLIC ACIDS
CHEMISTRY
COUMARINS
DRUGS
FLUORINE ISOTOPES
HEMATOLOGIC AGENTS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPES
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAGNETIC RESONANCE
MICROORGANISMS
NUCLEI
NUCLEIC ACIDS
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN COMPOUNDS
PYRIMIDINES
RESONANCE
RNA
SPECTRA
STABLE ISOTOPES
SULFUR COMPOUNDS
URACILS
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