Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, D-04103 Leipzig, Germany.
TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, 36/P Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad 500107, India.
J Magn Reson. 2018 Aug;293:82-91. doi: 10.1016/j.jmr.2018.06.003. Epub 2018 Jun 8.
In the present study, we exploit the light-induced hyperpolarization occurring on C nuclei due to the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect to boost the NMR signal intensity of selected protons via inverse cross-polarization. Such hyperpolarization transfer is implemented into H-detected two-dimensional C-H correlation magic-angle-spinning (MAS) NMR experiment to study protons in frozen photosynthetic reaction centers (RCs). As a first trial, the performance of such an experiment is tested on selectively C labeled RCs from the purple bacteria of Rhodobacter sphaeroides. We observed response from the protons belonging to the photochemically active cofactors in their native protein environment. Such an approach is a potential heteronuclear spin-torch experiment which could be complementary to the classical heteronuclear correlation (HETCOR) experiments for mapping proton chemical shifts of photosynthetic cofactors and to understand the role of the proton pool around the electron donors in the electron transfer process occurring during photosynthesis.
在本研究中，我们利用固态光致化学诱导动态核极化（photo-CIDNP）效应在 C 核上产生的光诱导超极化，通过反交叉极化来增强选定质子的 NMR 信号强度。这种超极化转移被应用于 H 检测二维 C-H 相关魔角旋转（MAS）NMR 实验中，以研究冷冻光合作用反应中心（RC）中的质子。作为首次尝试，我们在从红细菌 Rhodobacter sphaeroides 中选择性 C 标记的 RC 上测试了这种实验的性能。我们观察到了来自其天然蛋白质环境中光化学活性辅因子的质子的响应。这种方法是一种潜在的异核自旋实验，它可以与经典异核相关（HETCOR）实验互补，用于绘制光合作用辅因子的质子化学位移图谱，并了解质子池在光合作用过程中电子转移过程中电子供体周围的作用。
