ISOLATION AND CHARACTERIZATION OF N6-METHYLADENOSINE FROM ESCHERICHIA COLI VALINE TRANSFER RNA

A new minor component has been isolated from Escherichia coli tRNAValI which was identified as 6-methylamino-9-β-d-ribofuranosylpurine (N6-methyladenosine). Precautions were taken against possible conversion of N1-methyladenosine or N6-isopentenyladenosine to N6-methyladenosine during the isolation of the tRNAValI and subsequent liberation of the minor component from the tRNA. The N6-methyladenylic acid obtained by mild ribonuclease treatment of the tRNA was subsequently converted to the corresponding nucleoside and to the base by treatment with E. coli alkaline phosphatase and acid hydrolysis, respectively. The identity of the nucleotide, nucleoside and base thus obtained with corresponding authentic samples was established by comparison of their ultraviolet absorption spectra, paper chromatographic mobilities in several solvent systems, and by low- and high-resolution mass spectra. © 1969.