Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 7, 60438, Frankfurt, Germany.
Institute for Molecular Biosciences, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität Frankfurt, Max-von-Laue-Str. 9, 60438, Frankfurt, Germany.
Angew Chem Int Ed Engl. 2019 Jul 1;58(27):9140-9144. doi: 10.1002/anie.201904057. Epub 2019 May 27.
Up to now, NMR spectroscopic investigations of RNA have utilized imino proton resonances as reporters for base pairing and RNA structure. The nucleobase amino groups are often neglected, since most of their resonances are broadened beyond detection due to rotational motion around the C-NH bond. Here, we present C-detected NMR experiments for the characterization of all RNA amino groups irrespective of their motional behavior. We have developed a C(N)H-HDQC experiment that enables the observation of a complete set of sharp amino resonances through the detection of proton-NH double quantum coherences. Further, we present an "amino"-NOESY experiment to detect NOEs to amino protons, which are undetectable by any other conventional NOESY experiment. Together, these experiments allow the exploration of additional chemical shift information and inter-residual proton distances important for high-resolution RNA secondary and tertiary structure determination.
到目前为止，RNA 的 NMR 光谱研究利用亚氨基质子共振作为碱基配对和 RNA 结构的报告。核碱基的氨基基团通常被忽略，因为由于围绕 C-NH 键的旋转运动，它们的大部分共振都被展宽到无法检测的程度。在这里，我们提出了 C 检测 NMR 实验，用于表征所有 RNA 氨基基团，而不考虑它们的运动行为。我们开发了一种 C(N)H-HDQC 实验，通过检测质子-NH 双重量子相干，可以观察到完整的一组尖锐的氨基共振。此外，我们还提出了一种“氨基”-NOESY 实验来检测到氨基质子的 NOEs，这是任何其他常规 NOESY 实验都无法检测到的。总之，这些实验允许探索对高分辨率 RNA 二级和三级结构确定很重要的额外化学位移信息和残基间质子距离。
