Rennella Enrico, Sára Tomáš, Juen Michael, Wunderlich Christoph, Imbert Lionel, Solyom Zsofia, Favier Adrien, Ayala Isabel, Weinhäupl Katharina, Schanda Paul, Konrat Robert, Kreutz Christoph, Brutscher Bernhard
Institut de Biologie Structurale, Université Grenoble 1, 71 avenue des Martyrs, 38044 Grenoble Cedex 9, France.
Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Grenoble, France.
Nucleic Acids Res. 2017 Apr 20;45(7):4255-4268. doi: 10.1093/nar/gkx044.
Ensuring the correct folding of RNA molecules in the cell is of major importance for a large variety of biological functions. Therefore, chaperone proteins that assist RNA in adopting their functionally active states are abundant in all living organisms. An important feature of RNA chaperone proteins is that they do not require an external energy source to perform their activity, and that they interact transiently and non-specifically with their RNA targets. So far, little is known about the mechanistic details of the RNA chaperone activity of these proteins. Prominent examples of RNA chaperones are bacterial cold shock proteins (Csp) that have been reported to bind single-stranded RNA and DNA. Here, we have used advanced NMR spectroscopy techniques to investigate at atomic resolution the RNA-melting activity of CspA, the major cold shock protein of Escherichia coli, upon binding to different RNA hairpins. Real-time NMR provides detailed information on the folding kinetics and folding pathways. Finally, comparison of wild-type CspA with single-point mutants and small peptides yields insights into the complementary roles of aromatic and positively charged amino-acid side chains for the RNA chaperone activity of the protein.
确保细胞中RNA分子正确折叠对于多种生物学功能至关重要。因此，协助RNA形成功能活性状态的伴侣蛋白在所有生物体中都很丰富。RNA伴侣蛋白的一个重要特征是它们在执行活性时不需要外部能量源，并且它们与RNA靶标进行瞬时且非特异性的相互作用。到目前为止，对于这些蛋白的RNA伴侣活性的机制细节知之甚少。RNA伴侣的突出例子是细菌冷休克蛋白（Csp），据报道它们能结合单链RNA和DNA。在这里，我们使用先进的核磁共振光谱技术，以原子分辨率研究大肠杆菌主要冷休克蛋白CspA与不同RNA发夹结合时的RNA解链活性。实时核磁共振提供了关于折叠动力学和折叠途径的详细信息。最后，将野生型CspA与单点突变体和小肽进行比较，揭示了芳香族和带正电荷的氨基酸侧链对该蛋白RNA伴侣活性的互补作用。
