Institute of Biophysical Chemistry and ‡Institute of Physical and Theoretical Chemistry, Center for Biomolecular Magnetic Resonance Frankfurt, Goethe University Frankfurt , 60438 Frankfurt am Main, Germany.
J Am Chem Soc. 2014 Nov 5;136(44):15533-6. doi: 10.1021/ja509799s. Epub 2014 Oct 24.
Dynamic nuclear polarization (DNP)-enhanced solid-state NMR spectroscopy has been shown to hold great potential for functional studies of membrane proteins at low temperatures due to its great sensitivity improvement. There are, however, numerous applications for which experiments at ambient temperature are desirable and which would also benefit from DNP signal enhancement. Here, we demonstrate as a proof of concept that a significant signal increase for lipid bilayers under room-temperature conditions can be achieved by utilizing the Overhauser effect. Experiments were carried out on aligned bilayers at 400 MHz/263 GHz using a stripline structure combined with a Fabry-Perot microwave resonator. A signal enhancement of protons of up to -10 was observed. Our results demonstrate that Overhauser DNP at high field provides efficient polarization transfer within insoluble samples, which is driven by fast local molecular fluctuations. Furthermore, our experimental setup offers an attractive option for DNP-enhanced solid-state NMR on ordered membranes and provides a general perspective toward DNP at ambient temperatures.
动态核极化（DNP）增强的固态 NMR 光谱学由于其极大的灵敏度提高，已被证明在低温下对膜蛋白的功能研究具有很大的潜力。然而，还有许多需要在环境温度下进行实验的应用，并且也将受益于 DNP 信号增强。在这里，我们作为一个概念验证证明，通过利用 Overhauser 效应，可以在室温条件下为脂质双层获得显著的信号增加。实验是在 400 MHz/263 GHz 下使用带有 Fabry-Perot 微波谐振器的 stripline 结构在取向双层膜上进行的。观察到质子的信号增强高达-10。我们的结果表明，高场下的 Overhauser DNP 提供了在不溶性样品内有效的极化转移，这是由快速的局部分子波动驱动的。此外，我们的实验装置为有序膜的 DNP 增强固态 NMR 提供了一个有吸引力的选择，并为环境温度下的 DNP 提供了一个通用的视角。
