DEVELOPMENT OF A BIOSUPRAMOLECULAR NMR SYSTEM WITH A SUPERCONDUCTING MAGNET

我们的AM-400 NMR光谱仪（Bruker）内置了多核观测系统。在此基础上，研制了氘核磁共振固体探头。四极回波脉冲序列用于测量。最初，螺线管线圈内置在探头中，最初用于溶液NMR。90 μ s脉冲为12 μ s。简化了探头和匹配盒的电路。经过改进后，90 μ s的脉冲变为4 μ s左右。因此，我们已经建立了固态核磁共振系统，这可以作为本项目的起点。在甘油骨架中特异性氘代的磷脂得自E.由于生物样品中含有水分，样品管应垂直放置。尽管螺线管线圈中的功率非常有效，但样品管保持水平。所以我们决定改变线圈设计。将鞍型线圈附着在5 mm φ的玻璃管的表面上，将其垂直放置。8匝线圈适合0.94 cm^3的样品体积。该线圈的90 μ s脉冲为7.8 μ s。为了获得更大的功率，连接了一个高功率放大器。然而，在使用这种放大器时，探头发生了故障。由于我们的磁铁的孔径很窄，探头不足以避免电磁干扰。在没有放大器的情况下检查探头。通过使用60 mg氘代磷脂，获得了质量良好的^2 H-NMR谱。自旋晶格弛豫时间的测量使用反转恢复方法。180 μ m脉冲使功率谱的整个区域反转。这些结果表明，这种线圈可以用于磷脂双分子层的研究。因此，我们已经成功地建立了一个适合于生物膜研究的固体核磁共振系统。

A multinuclear observation system was built into our AM-400 NMR spectrometer (Bruker). Then, a solid-state probe head for deuterium NMR was developed. The quadrupole echo pulse sequence was used for the measurements. At first, a solenoid coil was built in a probe head, originally used for solution NMR. The 90ﾟ pulse was 12mus. The circuits of the probe head and matching box were simplified. After the modification, the 90ﾟ pulse became to be about 4mus. Thus, we have established the solid-state NMR system, which can be used for the start point of this project. phospholipids specifically deuterated in the glycerol backbone were obtained from E. coli cells cultured in the presence of perdeuterated glycerol.Since biological samples contain water, the sample tube should be held vertically. Although the power is very efficient in the solenoid coil, the sample tube is kept in horizontal. So we decided to change the coil design. A saddle type coil was attached on the surface of a glass tube with 5 mmphi, which was put in the vertical direction. The 8-turn coil fits to 0.94 cm^3 sample volume. The 90ﾟ pulse of this coil was 7.8mus. In order to get more power, a high power amplifier was connected. However, arching took place in the probe head on the use of this amplifier. Since the bore size of our magnet is narrow, the probe is not enough to avoid the arching. The probe was examined without the amplifier. By using 60 mg deuterated phospholipids, a ^2H-NMR spectrum in good quality was obtained. The spin-lattice relaxation time was measured using the inversion-recovery method. Whole region of the power pattern spectrum was inverted by the 180ﾟ pulse. These results show that this coil can be used for the investigation of the phospholipid bilayers. Thus, we have succeeded in establishing a solid-state NMR system suitable for biomembrane studies.