Pinard R, Payant C, Brakier-Gingras L
Département de Biochimie, Université de Montréal, Québec, Canada.
Biochemistry. 1995 Jul 25;34(29):9611-6. doi: 10.1021/bi00029a038.
Mutations at positions 13 (U-->A) and/or 914 (A-->U) of Escherichia coli 16S rRNA severely affect cell growth and protein synthesis, when expressed in vivo in a vector encoding an rrn operon under control of an inducible promoter. In vitro assays using extension inhibition indicate that the mutations interfere with the formation of the 30S translational initiation complex, which can account for their effect on cell growth. The two mutations destabilize an adjacent pseudoknot helix in which bases 17-19 pair to bases 916-918. This was shown by the increased binding of an oligodeoxyribonucleotide probe complementary to one strand of the pseudoknot helix, and by the increased reactivity to kethoxal of base G917 within this helix. These observations suggest that this pseudoknot helix participates in the formation of the 30S translational initiation complex.
当在编码rrn操纵子的载体中，于诱导型启动子控制下在体内表达时，大肠杆菌16S rRNA第13位（U→A）和/或第914位（A→U）的突变会严重影响细胞生长和蛋白质合成。使用延伸抑制的体外试验表明，这些突变会干扰30S翻译起始复合物的形成，这可以解释它们对细胞生长的影响。这两个突变会使相邻的假结螺旋不稳定，其中第17 - 19位碱基与第916 - 918位碱基配对。与假结螺旋一条链互补的寡脱氧核糖核苷酸探针结合增加，以及该螺旋内碱基G917对乙二醛的反应性增加，都证明了这一点。这些观察结果表明，这个假结螺旋参与了30S翻译起始复合物的形成。
