Biophysics Laboratories, School of Biological Sciences, Institute of Biomedical and Biomolecular Sciences, University of Portsmouth, Portsmouth, PO1 2DT, UK.
Nucleic Acids Res. 2012 Sep 1;40(17):8698-710. doi: 10.1093/nar/gks582. Epub 2012 Jun 22.
In , the RNA binding protein and chaperone Hfq (VcHfq) facilitates the pairing of the quorum regulatory RNA (Qrr) small regulatory RNAs (sRNAs) to the 5' untranslated regions of the mRNAs for a number of global regulators that modulate the expression of virulence genes. This Qrr-mediated sRNA circuit is an attractive antimicrobial target, but characterization at the molecular level is required for this to be realized. Here, we investigate the interactions between VcHfq and the Qrr sRNAs using a variety of biochemical and biophysical techniques. We show that the ring-shaped VcHfq hexamer binds the Qrrs with 1:1 stoichiometry through its proximal face, and the molecular envelope of the VcHfq-Qrr complex is experimentally determined from small angle scattering data to present the first structural glimpse of a Hfq-sRNA complex. This structure reveals that the VcHfq protein does not change shape on complex formation but the RNA does, suggesting that a chaperone role for VcHfq is a critical part of the VcHfq-Qrr interaction. Overall, these studies enhance our understanding of VcHfq-Qrr interactions.
在 Vibrio cholerae 中，RNA 结合蛋白和伴侣蛋白 Hfq（VcHfq）促进了数量众多的全局调控因子的 mRNA 的 5'非翻译区与群体感应调控 RNA（Qrr）小调控 RNA（sRNA）的配对，这些全局调控因子调节毒力基因的表达。这种 Qrr 介导的 sRNA 回路是一个有吸引力的抗菌药物靶点，但要实现这一点，需要在分子水平上进行表征。在这里，我们使用多种生化和生物物理技术研究了 VcHfq 与 Qrr sRNA 之间的相互作用。我们表明，环形 VcHfq 六聚体通过其近端面以 1:1 的化学计量比与 Qrrs 结合，并且从小角度散射数据确定了 VcHfq-Qrr 复合物的分子包络，从而首次呈现了 Hfq-sRNA 复合物的结构。该结构表明，VcHfq 蛋白在形成复合物时不会改变形状，而 RNA 会改变形状，这表明 VcHfq 的伴侣蛋白作用是 VcHfq-Qrr 相互作用的关键部分。总体而言，这些研究增进了我们对 VcHfq-Qrr 相互作用的理解。
