Roy S, Papastavros M Z, Sanchez V, Redfield A G
Biochemistry. 1984 Sep 11;23(19):4395-400. doi: 10.1021/bi00314a024.
5N1-Labeled hypoxanthine and 1,3-15N-labeled uracil were synthesized chemically and used to prepare labeled yeast tRNAPhe biosynthetically. Maps (500 MHz) of 15N chemical shift vs. proton chemical shift were obtained, for each ring NH group, by means of INDOR (difference heterodecoupling) and also by means of a proton-observe two-dimensional method involving coherences of forbidden resonances of the NH system. Resonances of GC11, T54-m1A58, GU4, and A psi 31 were confirmed, assigned, or reassigned. psi 39 was found to be in anti conformation, not syn as previously stated. Almost all the uracil NH group resonances could be separated, but most of the GC resonances are too close even in two dimensions to be separately resolved with the observed 20-Hz 15N line width.
化学合成了5N1标记的次黄嘌呤和1,3-15N标记的尿嘧啶，并用于生物合成制备标记的酵母苯丙氨酸tRNA。通过INDOR（差分异核去耦）以及涉及NH系统禁戒共振相干性的质子观测二维方法，获得了每个环NH基团的15N化学位移与质子化学位移的图谱（500兆赫）。确认、指定或重新指定了GC11、T54-m1A58、GU4和Aψ31的共振峰。发现ψ39处于反式构象，而非如先前所述的顺式构象。几乎所有尿嘧啶NH基团的共振峰都能被分离，但即使在二维图谱中，大多数GC共振峰也靠得太近，以至于在观测到的20赫兹15N线宽下无法单独分辨。
