Muramatsu T, Yokoyama S, Horie N, Matsuda A, Ueda T, Yamaizumi Z, Kuchino Y, Nishimura S, Miyazawa T
Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.
J Biol Chem. 1988 Jul 5;263(19):9261-7. doi: 10.1351/pac198961030573.
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.
已从大肠杆菌B中分离出一种特异识别密码子AUA的次要异亮氨酸tRNA（tRNA（次要Ile）），并且在反密码子的第一位发现了一种修饰核苷N⁺（原田，F.，和西村，S.（1974年）《生物化学》13卷，300 - 307页）。在本研究中，从大肠杆菌A19中纯化出tRNA（次要Ile），并通过高效液相色谱法制备了核苷N⁺，其数量（0.6 A₂₆₀单位）足以用于化学结构测定。通过400兆赫¹H核磁共振分析，发现核苷N⁺具有一个嘧啶部分和一个赖氨酸部分，其中赖氨酸的ε氨基参与了这两个部分之间的连接。结合核磁共振分析和质谱分析，确定核苷N⁺的结构为4 - 氨基 - 2 - （N⁶ - 赖氨酸基） - 1 - （β - D - 呋喃核糖基）嘧啶鎓（“lysidine”），并通过化学合成得以证实。Lysidine是一种带有赖氨酸部分的新型修饰胞苷，带有一个正电荷。可能由于这种独特的结构，反密码子第一位的lysidine识别密码子第三位的腺苷而非鸟苷。
