The importance of helix P1 stability for structural pre-organization and ligand binding affinity of the adenine riboswitch aptamer domain.
The importance of helix P1 stability for structural pre-organization and ligand binding affinity of the adenine riboswitch aptamer domain.
复制标题
DOI：
10.4161/rna.29439
复制
发表时间：
2014
期刊：
影响因子：
4.1
通讯作者：
Schwalbe H
中科院分区：
文献类型：
--
作者：
Nozinovic S;Reining A;Kim YB;Noeske J;Schlepckow K;Wöhnert J;Schwalbe H
我们在这里报告了通过核磁共振和荧光光谱对转录腺嘌呤感应核糖开关（pbuE）的适体结构域进行的深入表征。通过核磁共振研究，对具有不同长度螺旋 P1 的两个适体序列的结构进行了表征，P1 是参与核糖开关构象转换的中心元件。氢键相互作用可以在核苷酸分辨率下绘制，提供有关二级和三级结构、结构同质性和动力学的信息。我们的研究表明，螺旋 P1 的延长不仅对 apo 适配体结构域的局部结构而且对整体结构都有显着影响。对停流荧光研究获得的动力学和热力学数据的分析表明，稳定螺旋 P1 引起的结构差异与配体结合亲和力的变化有关。这些结果为嘌呤传感核糖开关的结构和功能的序列依赖性微调提供了新的见解。
We report here an in-depth characterization of the aptamer domain of the transcriptional adenine-sensing riboswitch (pbuE) by NMR and fluorescence spectroscopy. By NMR studies, the structure of two aptamer sequences with different lengths of the helix P1, the central element involved in riboswitch conformational switching, was characterized. Hydrogen-bond interactions could be mapped at nucleotide resolution providing information about secondary and tertiary structure, structure homogeneity and dynamics. Our study reveals that the elongation of helix P1 has pronounced effects not only on the local but on the global structure of the apo aptamer domain. The structural differences induced by stabilizing helix P1 were found to be linked to changes of the ligand binding affinity as revealed from analysis of kinetic and thermodynamic data obtained from stopped-flow fluorescence studies. The results provide new insight into the sequence-dependent fine tuning of the structure and function of purine-sensing riboswitches.