Characterizing slow chemical exchange in nucleic acids by carbon CEST and low spin-lock field R(1ρ) NMR spectroscopy.
Characterizing slow chemical exchange in nucleic acids by carbon CEST and low spin-lock field R(1ρ) NMR spectroscopy.
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DOI：
10.1021/ja409835y
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发表时间：
2014-01-08
影响因子：
15
通讯作者：
Zhang Q
中科院分区：
文献类型：
--
作者：
Zhao B;Hansen AL;Zhang Q
各种构象状态之间的动态交换的定量表征提供了许多监管RNA功能的分子基础的重要见解。在这里，我们提出了一个应用程序的核酸优化的碳化学交换饱和转移（CEST）和低自旋锁场R1ρ弛豫分散（RD）NMR实验在表征缓慢的化学交换的核酸，否则很难，如果不是不可能被量化的ZZ-交换NMR实验。我们展示了在无配体状态下的47-核苷酸氟化物核糖开关上的应用，其中碱基和糖碳的CEST和R1ρ RD谱显示了涉及稀疏填充（p ~ 10%）和短寿命（τ ~ 10 ms）NMR“不可见”状态的缓慢交换动力学。CEST和低自旋锁定场R1ρ RD实验在研究慢交换中的效用在表征慢至~60 s−1的交换中得到了进一步验证。
Quantitative characterization of dynamic exchange between various conformational states provides essential insights into the molecular basis of many regulatory RNA functions. Here, we present an application of nucleic-acid-optimized carbon chemical exchange saturation transfer (CEST) and low spin-lock field R1ρ relaxation dispersion (RD) NMR experiments in characterizing slow chemical exchange in nucleic acids that is otherwise difficult if not impossible to be quantified by the ZZ-exchange NMR experiment. We demonstrated the application on a 47-nucleotide fluoride riboswitch in the ligand-free state, for which CEST and R1ρ RD profiles of base and sugar carbons revealed slow exchange dynamics involving a sparsely populated (p ~ 10%) and shortly lived (τ ~ 10 ms) NMR “invisible” state. The utility of CEST and low spin-lock field R1ρ RD experiments in studying slow exchange was further validated in characterizing an exchange as slow as ~60 s−1.