铕离子对tRNA^(Phe)结构影响的NMR研究  

STUDY ON EFFECT OF EUROPIUM IONS ON tRNA Phe STRUCTURE WITH IMINO PROTON NMR SPECTROSCOPY

作　　者：涂华民[1] 杨燕生[1] 龚孟濂[1] 吴亦洁[2] 张洪杰[2] 

机构地区：[1]中山大学化学系 [2]中国科学院长春应用化学研究所

出　　处：《波谱学杂志》1998年第2期157-162,共6页Chinese Journal of Magnetic Resonance

基　　金：国家"攀登"计划;中科院长春应化所稀士化学和物理开放实验室基金

摘　　要：采用ＮＭＲ波谱方法研究了溶液中铕离子对酵母苯丙氨酸转移核糖核酸（ｐｈｅｎｙｌａｌａ－ｎｉｎｅｔｒａｎｓｆｅｒｒｉｂｏｎｕｃｌｅｉｃａｃｉｄ，简称ｔＲＮＡＰｈｅ）结构和构象变化的影响．Ｅｕ３＋离子对ｔＲＮＡＰｈｅ亚胺质子范围的１ＨＮＭＲ谱具有特殊的影响，酵母ｔＲＮＡＰｈｅ亚胺质子谱作为Ｅｕ３＋浓度函数的研究表明位于扩大二氢尿嘧啶螺旋（Ｄ－螺旋）的端梢三级碱基对Ｇ１５·Ｃ４８明显地受加入Ｅｕ３＋的影响（向低场位移０．８５）；堆积在Ｇ１５·Ｃ４８上的Ｕ８·Ａ１４碱基对在存有１～２个Ｍｇ２＋离子下亦受加入Ｅｕ３＋的影响．酵母ｔＲＮＡＰｈｅ中可能受到Ｅｕ３＋影响的另一亚胺质子为Ｇ１９·Ｃ５６三级碱基对，由于Ｇ１９·Ｃ５６的亚胺质子共振位于高度叠加的１２．６与１２．２之间，其归属仅供参考．该碱基对有助于Ｄ－环对ＴΨＣ环的联接．配位Ｅｕ３＋引起ｔＲＮＡ分子构象的变化并且导致一些谱峰向高场或低场位移．The structure of phenylalanine transfer ribonucleic acid (tRNA Phe ) in solution was explored by 1H nuclear magnetic resonance ( 1H NMR) spectroscopy to evaluate the effect of europium ions (Eu 3+ ) on the structural and conformational change. Trivalent ions Eu 3+ have specific effects on the imino proton region of the 1H NMR spectra of yeast tRNA Phe . The dependence of the imino proton spectra of yeast tRNA Phe as a function of Eu 3+ concentration was examined, and the results suggested that the tertiary base pair G 15 \5C 48 , which is located on the terminal in the augmented dihydrouridine helix (D helix) was markedly affected by Eu 3+ (shifted downfield by 0.85). Base pair U 8\5A 14 in yeast tRNA Phe , which are stacked on G 15 \5C 48 , was also affected by added Eu 3+ when 1～2Mg 2+ ions were also present. Another imino proton that may be affected by Eu 3+ in yeast tRNA Phe is that of the tertiary base pair G 19 \5C 56 . The assignment of this resonance in yeast tRNA Phe is tentative since it is located in the region of highly overlapping resonances between 12.6 and 12.2. This base pair helps to anchor the D loop to the TΨC loop. The binding of Eu 3+ caused conformational change of tRNA, which is responsible for shifts to upfield or downfield in 1H NMR spectra.

关 键 词：铕离子 转移核糖核酸 NMR 生物分子结构 

分 类 号：Q522.02[生物学—生物化学]