Mai W, Hu W, Wang C, Cross T A
Institute of Molecular Biophysics, Florida State University, Tallahassee 32306-3006.
Protein Sci. 1993 Apr;2(4):532-42. doi: 10.1002/pro.5560020405.
Chemical shifts observed from samples that are uniformly aligned with respect to the magnetic field can be used as very high-resolution structural constraints. This constraint takes the form of an orientational constraint rather than the more familiar distance constraint. The accuracy of these constraints is dependent upon the quality of the tensor characterization. Both tensor element magnitudes and tensor orientations with respect to the molecular frame need to be considered. Here these constraints have been used to evaluate models for the channel conformation of gramicidin A. Of the three models used, the one experimentally derived model of gramicidin in sodium dodecyl sulfate micelles fits the data least well.
从相对于磁场均匀排列的样品中观察到的化学位移可作为非常高分辨率的结构约束。这种约束采取取向约束的形式，而不是更常见的距离约束。这些约束的准确性取决于张量表征的质量。需要考虑张量元素大小和相对于分子框架的张量取向。在这里，这些约束已被用于评估短杆菌肽A通道构象的模型。在所使用的三个模型中，实验推导的短杆菌肽在十二烷基硫酸钠胶束中的模型与数据拟合得最差。
