O'Connor M, Dahlberg A E
Section of Biochemistry, Brown University, Providence, RI 02912.
Proc Natl Acad Sci U S A. 1993 Oct 1;90(19):9214-8. doi: 10.1073/pnas.90.19.9214.
A plasmid carrying a mutation in the highly conserved base U2555 in Escherichia coli 23S rRNA was isolated by selecting for suppression of the -1 frameshift mutation trpE91. U2555 is normally protected in chemical footprinting experiments by the aminoacyl residue of A-site-bound tRNA. Substitution of U2555 by adenine or guanine (but not by cytosine) increased readthrough of all three stop codons and +1 and -1 frameshifting. These effects on translational fidelity demonstrate the importance of U2555 for selection of the correct tRNA at the ribosomal A site.
通过筛选对-1移码突变trpE91的抑制作用，分离出了携带大肠杆菌23S rRNA中高度保守碱基U2555发生突变的质粒。在化学足迹实验中，U2555通常受到A位点结合的tRNA的氨酰基残基的保护。用腺嘌呤或鸟嘌呤（而非胞嘧啶）取代U2555，增加了所有三个终止密码子的通读以及+1和-1移码。这些对翻译保真度的影响证明了U2555对于在核糖体A位点选择正确tRNA的重要性。
