Wells B D
Nucleic Acids Res. 1984 Feb 24;12(4):2157-70. doi: 10.1093/nar/12.4.2157.
The intrinsic fluorescence of the Wye base was used to study the conformational change of the anticodon loop of yeast tRNAPhe brought about by the addition of magnesium. The fluorescence emission and excitation spectra show dramatic changes as magnesium is added to the solution. The rotational relaxation time changes from 6 nsec without added magnesium to 33 nsec with 10 mM magnesium at an ionic strength of 0.1 M. Stern-Volmer quenching by iodide or iodoethanol shows greater access of the base to the quencher with no added magnesium. A plausible interpretation of this data is that the base stack of the anticodon loop is altered by tilting or twisting the Wye base with respect to the adjacent bases and the base becomes parallel to its neighbors upon the addition of magnesium.
利用怀碱基的固有荧光来研究添加镁离子后酵母苯丙氨酸转运核糖核酸（tRNAPhe）反密码子环的构象变化。当向溶液中添加镁离子时，荧光发射光谱和激发光谱显示出显著变化。在离子强度为0.1 M的条件下，旋转弛豫时间从不添加镁离子时的6纳秒变为添加10 mM镁离子时的33纳秒。用碘化物或碘乙醇进行的斯特恩-沃尔默猝灭实验表明，在不添加镁离子时，该碱基更容易被猝灭剂接近。对这些数据的一种合理的解释是，反密码子环的碱基堆积通过使怀碱基相对于相邻碱基倾斜或扭曲而发生改变，并且在添加镁离子后该碱基与其相邻碱基变得平行。
