Real-time evidence for EF-G-induced dynamics of helix 44 in 16S rRNA.
Real-time evidence for EF-G-induced dynamics of helix 44 in 16S rRNA.
复制标题
EF-G 诱导的 16S rRNA 螺旋 44 动力学的实时证据。
DOI：
10.1016/j.jmb.2012.05.012
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发表时间：
2012
影响因子：
5.6
通讯作者：
Hill,WalterE
中科院分区：
文献类型：
--
作者：
Tanner,DouglasR;Hedrick,EmilyG;Hill,WalterE
16 S核糖体RNA（rRNA）的倒数第二个茎环，螺旋44，在核糖体功能中起着核心作用。使用时间分辨硫酸二甲酯（DMS）探测，我们分析了时间依赖性的修改，发生在特定的碱基在这个螺旋附近的解码区，导致从结合的延伸因子G（EF-G）在各种形式。当EF-G-GTP与70 S核糖体结合时，碱基A1492和A1493立即受到保护，而该区域的其他碱基没有变化或显示出增强的修饰。当apo-EF-G与70 S核糖体结合并加入GTP时，在碱基A1492和A1493处发生大量瞬时时间依赖性增强，在碱基A1483处发生稍少的增强，所有这些都发生在前45 ms内。当mRNA和脱酰化的tRNA与70 S核糖体结合并加入EF-G-GTP时，碱基A1492和A1493再次显示出显著和持续的增强，而碱基A1408、A1413和A1418都显示出时间依赖性保护。这些结果提供了主要的，实时的证据表明，EF-G诱导直接或间接的结构变化，在该地区的EF-G是结合和GTP被水解。
The penultimate stem–loop of 16S ribosomal RNA (rRNA), helix 44, plays a central role in ribosome function. Using time-resolved dimethyl sulfate (DMS) probing, we have analyzed time-dependent modifications that occur at specific bases in this helix near the decoding region, resulting from the binding of elongation factor G (EF-G) in various forms. When EF-G-GTP is bound to 70S ribosomes, bases A1492 and A1493 are immediately protected, while other bases in the region show either no change or enhanced modification. When apo-EF-G is bound to 70S ribosomes and GTP is added, substantial transient time-dependent enhancement occurs at bases A1492 and A1493, with somewhat less enhancement occurring at base A1483, all in the first 45 ms. When mRNA and deacylated tRNAs are bound to the 70S ribosome and EF-G-GTP is added, bases A1492 and A1493 again show substantial and continued enhancement, while bases A1408, A1413, and A1418 all show time-dependent protection. These results provide primary, real-time evidence that EF-G induces direct or indirect structural changes in this region as EF-G is bound and as GTP is hydrolyzed.