Jørgensen T, Siboska G E, Wikman F P, Clark B F
Eur J Biochem. 1985 Nov 15;153(1):203-9. doi: 10.1111/j.1432-1033.1985.tb09287.x.
Footprinting studies involving radioactively end-labelled tRNA species bound at either the ribosomal P- or A-site have yielded information that the tRNA's conformation is different in the two sites. Appropriate controls showed the relevance of using poly(U)-directed tRNAPhe binding in the P-site and Phe-tRNAPhe in the A-site. Digestion of the tRNA species was effected by RNases T1, T2 and cobra venom RNase. Experiments were performed with tRNAs 32P-labelled at either end to establish positions of primary cuts more confidently. In addition to the common protection of the aminoacyl-stem and anticodon-arm, footprinting experiments revealed striking differences in the accessibility of the T- and D-loops of tRNAs bound in the P- and A-sites. We observed a more open structure for the tRNA in the A-site. These results are consistent with a dynamic structure of tRNA during the translocation step of protein biosynthesis.
足迹分析研究涉及与核糖体P位点或A位点结合的放射性末端标记的tRNA种类，这些研究得出的信息表明，tRNA在这两个位点的构象不同。适当的对照显示了在P位点使用聚（U）指导的tRNAPhe结合以及在A位点使用苯丙氨酰 - tRNAPhe的相关性。tRNA种类的消化由核糖核酸酶T1、T2和眼镜蛇毒核糖核酸酶进行。使用在两端都进行了32P标记的tRNA进行实验，以更可靠地确定初次切割的位置。除了对氨酰基茎和反密码子臂的常见保护外，足迹分析实验还揭示了结合在P位点和A位点的tRNA的T环和D环可及性存在显著差异。我们观察到A位点的tRNA结构更开放。这些结果与蛋白质生物合成转位步骤中tRNA的动态结构一致。
