Abstract：
Bacterial cell walls are gigadalton-large cross-linked polymers with a wide range of motional amplitudes, including rather rigid as well as highly flexible parts. Magic-angle spinning NMR is a powerful method to obtain atomic-level information about intact cell walls. Here we investigate sensitivity and information content of different homonuclear 13C13C and heteronuclear 1H15N, 1H13C and 15N13C correlation experiments. We demonstrate that a CPMAS CryoProbe yields ca. 8-fold increased signal-to-noise over a room-temperature probe, or a ca. 3-4-fold larger per-mass sensitivity. The increased sensitivity allowed to obtain high-resolution spectra even on intact bacteria. Moreover, we compare resolution and sensitivity of 1H MAS experiments obtained at 100 kHz vs. 55 kHz. Our study provides useful hints for choosing experiments to extract atomic-level details on cell-wall samples.
摘要：
细菌细胞壁是gigadalton-large交联聚合物，具有广泛的运动幅度，包括相当刚性以及高度灵活的部分。魔角旋转NMR是获得有关完整细胞壁的原子级信息的强大方法。在这里，我们研究了不同同核13C13C和异核1H15N的灵敏度和信息含量，1H13C和15N13C相关实验。我们证明了CPMASCryoProbe的产量约为。与室温探头相比，信噪比增加了8倍，或者CA.3-4倍大每质量灵敏度。即使在完整的细菌上，增加的灵敏度也可以获得高分辨率的光谱。此外，我们比较了在100kHz下获得的1HMAS实验的分辨率和灵敏度55kHz。我们的研究为选择实验以提取细胞壁样品的原子级细节提供了有用的提示。
