Multispin Recoupling in Solid-State Nuclear Magnetic Resonance

核磁共振（NMR）是一种技术，它利用许多原子的原子核作为微小的无线电发射器，以精确定义的频率发射无线电信号，可以通过仔细调谐的检测器检测到。发射的频率取决于特定原子核的电子环境。这种效应被称为化学位移，并允许NMR用于获得物质化学成分的信息。如果两个磁核在空间中彼此靠近，它们会轻微地相互影响，就像两个并排放置的条形磁铁一样。可以利用这种效应来估计磁核之间的距离。人们可以通过估计许多核间距来建立蛋白质分子三维结构的精确图像。目前的固体核磁共振实验能够准确地估计这些核间距。然而，现有的方法只有在分子只包含两个相同同位素类型的磁核时才能很好地工作。这类样品可以用同位素标记方法合成，但该过程既费力又昂贵。在这个项目中，我们将开发的方法，使许多核间距测量同一个多标记的样品。这将大大加快利用NMR估算固态分子结构的过程。这将允许确定分子的三维结构，如膜蛋白，大大增加了我们对化学信号处理系统的理解，这些系统对我们体内细胞的生命过程至关重要。

Nuclear Magnetic Resonance (NMR) is a technique which uses the fact that the nuclei of many atoms act as tiny radiotransmitters, emitting radio signals at precisely-defined frequencies, which can be detected by a carefully-tuned detector. The frequencies which are emitted depend on the electronic environment of a particular nucleus. This effect is called the chemical shift and allows NMR to be used to obtain information on the chemical composition of a substance. If two magnetic nuclei are close to each other in space, they slightly influence each other, rather like two bar magnets placed side-by-side. It is possible to use this effect to estimate the distances between the magnetic nuclei. One can build up an accurate picture of the three-dimensional structure of a protein molecule by estimating many internuclear distances. Current solid-state NMR experiments are able to estimate these internuclear distances accurately. However, existing methods only work well if the molecule only contains two magnetic nuclei of the same isotopic type. Samples of this kind may be synthesized using isotopic labelling methods but the procedure is laborious and expensive. In this project, we will develop methods which allow many internuclear distances to be measured on the same multiply-labelled sample. This will greatly speed up the procedures for estimating molecular structures in the solid state by using NMR. This will allow the determination of the three-dimensional structures of molecules such as membrane proteins, adding greatly to our understanding of the chemical signal processing systems which are vital to the life processes of the cells in our bodies.