Conformation and mechanical property of rpoS mRNA inhibitory stem studied by optical tweezers and X-ray scattering
Conformation and mechanical property of rpoS mRNA inhibitory stem studied by optical tweezers and X-ray scattering
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光镊和X射线散射研究rpoS mRNA抑制茎的构象和机械性能
DOI：
10.1371/journal.pone.0222938
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发表时间：
2019-09-26
期刊：
影响因子：
3.7
通讯作者：
Gong, Qingguo
中科院分区：
文献类型：
--
作者：
Hu, Xinyao;Li, Xuanling;Gong, Qingguo
3'下游抑制茎在将rpoS mRNA 5'非翻译区锁定在自我抑制状态中起着至关重要的作用。在这里，我们使用光镊研究了在 Mg2+ 不存在和存在的情况下 rpoS 抑制茎的展开/重折叠。通过确认该 RNA 形成了规范的 RNA 三向连接，我们发现添加 Mg2+ 降低了 RNA 连接的自由能，而无需重新排列其二级结构。我们怀疑自由能的增加可能会改变 rpoS 不同茎的相对方向，并通过小角 X 射线散射证实了这一点。这种构象的改变可能会改善 sRNA 和 rpoS RNA 抑制茎之间的 Hfq 桥接退火。我们通过将光镊与X射线散射方法相结合，建立了一条分析RNA构象和折叠动力学变化的便捷途径。该路线可以很容易地应用于其他RNA结构和配体RNA的研究。
3' downstream inhibitory stem plays a crucial role in locking rpoS mRNA 5' untranslated region in a self-inhibitory state. Here, we used optical tweezers to study the unfolding/refolding of rpoS inhibitory stem in the absence and presence of Mg2+. We found adding Mg2+ decreased the free energy of the RNA junction without re-arranging its secondary structure, through confirming that this RNA formed a canonical RNA three-way junction. We suspected increased free energy might change the relative orientation of different stems of rpoS and confirmed this by small angle X-ray scattering. Such changed conformation may improve Hfq-bridged annealing between sRNA and rpoS RNA inhibitory stem. We established a convenient route to analyze the changes of RNA conformation and folding dynamics by combining optical tweezers with X-ray scattering methods. This route can be easily applied in the studies of other RNA structure and ligand-RNA.