FORMATION OF THE CENTRAL PSEUDOKNOT IN 16S RIBOSOMAL-RNA IS ESSENTIAL FOR INITIATION OF TRANSLATION
FORMATION OF THE CENTRAL PSEUDOKNOT IN 16S RIBOSOMAL-RNA IS ESSENTIAL FOR INITIATION OF TRANSLATION
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DOI：
10.1002/j.1460-2075.1993.tb06076.x
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发表时间：
1993-10-01
期刊：
影响因子：
11.4
通讯作者：
DEBOER, HA
中科院分区：
文献类型：
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作者：
BRINK, MF;VERBEET, MP;DEBOER, HA
假定的由大肠杆菌 16S rRNA 的 9-13/21-25 和 17-19/916-918 区域形成的中心假结在原核生物和真核生物物种中在系统发育上是保守的。该假结位于 16S rRNA 二级结构的中心，连接该分子的三个主要结构域。我们通过改变碱基配对残基 C18 和 G917 向该假结引入突变，并使用“专门的”核糖体系统在体内研究了此类突变对核糖体活性的影响。与具有野生型假结的核糖体相比，在第18位含有A、G或U残基的核糖体的翻译活性显着降低，而在第18位和第917位具有互补碱基的突变核糖体的翻译活性处于野生型水平。那些不能形成假结的突变体的翻译活性降低是因为它们不能形成70S核糖体复合物。这些结果表明，16S rRNA 中 18 和 917 位任何碱基配对残基可能形成中心假结，这对于完成起始过程至关重要。
The postulated central pseudoknot formed by regions 9-13/21-25 and 17-19/916-918 of 16S rRNA of Escherichia coli is phylogenetically conserved in prokaryotic as well eukaryotic species. This pseudoknot is located at the center of the secondary structure of the 16S rRNA and connects the three major domains of this molecule. We have introduced mutations into this pseudoknot by changing the base-paired residues C18 and G917, and the effect of such mutations on the ribosomal activity was studied in vivo, using a 'specialized' ribosome system. As compared with ribosomes having the wild-type pseudoknot, the translational activity of ribosomes containing an A, G or U residue at position 18 was dramatically reduced, while the activity of mutant ribosomes having complementary bases at positions 18 and 917 was at the wild-type level. The reduced translational activity of those mutants that are incapable of forming a pseudoknot was caused by their inability to form 70S ribosomal complexes. These results demonstrate that the potential formation of a central pseudoknot in 16S rRNA with any base-paired residues at positions 18 and 917 is essential to complete the initiation process.