title: A novel lysine-substituted nucleoside in the first position of the anticodon of minor isoleucine tRNA from Escherichia coli.
abstract: A minor species of isoleucine tRNA (tRNA(minor Ile)) specific to the codon AUA has been isolated from Escherichia coli B and a modified nucleoside N+ has been found in the first position of the anticodon (Harada, F., and Nishimura, S. (1974) Biochemistry 13, 300-307). In the present study, tRNA(minor Ile)) was purified from E. coli A19, and nucleoside N+ was prepared, by high-performance liquid chromatography, in an amount (0.6) A260 units) sufficient for the determination of chemical structures. By 400 MHz 1H NMR analysis, nucleoside N+ was found to have a pyrimidine moiety and a lysine moiety, the epsilon amino group of which was involved in the linkage between these two moieties. From the NMR analysis together with mass spectrometry, the structure of nucleoside N+ was determined as 4-amino-2-(N6-lysino)-1-(beta-D-ribofuranosyl)pyrimidinium ("lysidine"), which was confirmed by chemical synthesis. Lysidine is a novel type of modified cytidine with a lysine moiety and has one positive charge. Probably because of such a unique structure, lysidine in the first position of anticodon recognizes adenosine but not guanosine in the third position of codon.
mesh_terms: D000926:Anticodon; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D007700:Kinetics; D008239:Lysine; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009705:Nucleosides; D012343:RNA, Transfer; D012345:RNA, Transfer, Amino Acid-Specific / Q000235:genetics*; D012355:RNA, Transfer, Ile / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000926:Anticodon; D009705:Nucleosides; D012345:RNA, Transfer, Amino Acid-Specific; D012355:RNA, Transfer, Ile; D012343:RNA, Transfer; D008239:Lysine