In-cell NMR spectroscopy provides precious structural and functional information on biological macromolecules in their native cellular environment at atomic resolution. However, the intrinsic low sensitivity of NMR imposes a big limitation in the applicability of the methodology. In this respect, the recently developed commercial 1.2 GHz NMR spectrometer is expected to introduce significant benefits. However, cell samples may suffer from detrimental effects at ultrahigh fields, that must be carefully evaluated. Here we show the first in-cell NMR spectra recorded at 1.2 GHz on human cells, and we compare resolution and sensitivity against those obtained at 900 and 950 MHz. To evaluate the effects of different spin relaxation rates, SOFAST-HMQC and BEST-TROSY spectra were recorded on intracellular α-synuclein and carbonic anhydrase. Major improvements are observed at 1.2 GHz when analyzing unfolded proteins, such as α-synuclein, while the TROSY scheme improves the resolution for both globular and unfolded proteins.

细胞内核磁共振波谱以原子分辨率提供了生物大分子在其天然细胞环境中的宝贵结构和功能信息。然而，核磁共振固有的低灵敏度对该方法的适用性施加了很大的限制。在这方面，最近开发的商用 1.2 GHz 核磁共振光谱仪有望带来显着的好处。然而，细胞样品在超高场可能会受到不利影响，必须仔细评估。在这里，我们展示了在人类细胞上以 1.2 GHz 记录的第一个细胞内 NMR 光谱，并且我们将分辨率和灵敏度与在 900 和 950 MHz 下获得的光谱进行了比较。为了评估不同自旋弛豫率的影响，在细胞内α-突触核蛋白和碳酸酐酶上记录了 SOFAST-HMQC 和 BEST-TROSY 光谱。