Tamura K
Biophysical Chemistry Laboratory, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
FEBS Lett. 1994 Oct 17;353(2):173-6. doi: 10.1016/0014-5793(94)01038-2.
Peptidyl transfer is a key step in the process of protein biosynthesis. To examine the role of the universal CCA terminal sequence of tRNA in the process of peptidyl transfer, various mutant transcripts of Escherichia coli valine tRNA were constructed. Peptidyl transferase activity, monitored by the 'fragment reaction' with a slight modification, was decreased by mutation at any one base of CCA. The effect of mutation was moderate in the UCA, CUA and CCG mutants. Replacement of A76 by a pyrimidine nucleotide, or replacement of either C74 or C75 by a purine nucleotide caused a marked decrease in the activity. These findings suggested that the universal CCA terminus of tRNA makes a functional interaction with ribosomal RNA by base-pairing.
肽基转移是蛋白质生物合成过程中的关键步骤。为了研究tRNA通用CCA末端序列在肽基转移过程中的作用，构建了大肠杆菌缬氨酸tRNA的各种突变转录本。通过对“片段反应”进行轻微修改来监测肽基转移酶活性，CCA的任何一个碱基发生突变都会使其降低。UCA、CUA和CCG突变体的突变效应适中。将A76替换为嘧啶核苷酸，或将C74或C75中的任何一个替换为嘌呤核苷酸都会导致活性显著降低。这些发现表明，tRNA的通用CCA末端通过碱基配对与核糖体RNA进行功能相互作用。
