Lamellar unit cell reconstruction from neutron and X-ray diffraction data provides information about the disposition and position of molecules and molecular segments with respect to the bilayer. When supplemented with the judicious use of molecular deuteration, the technique probes the molecular interactions and conformations within the bilayer membrane and the water layer which constitute the crystallographic unit cell. The perspective is model independent, and potentially, with a higher degree of resolution than is available with other techniques. In the case of neutron diffraction the measurement consists of carefully normalised diffracted intensity under conditions of contrast variation of the water layer. The subsequent Fourier reconstruction of the unit cell is made using the phase information from variation of peak intensities with contrast. Although the phase problem is not as easily solved for the corresponding X-ray measurements, an intuitive approach can often suffice. Here we discuss the two complimentary techniques as probes of scattering length density profiles of a bilayer, and how such a perspective provides information about the location and orientation of molecules within or between lipid bilayers. Within the basic paradigm of lamellar phases this method has provided, for example, detailed insights into the location and interaction of cryoprotectants and stress proteins, of the mechanisms of actions of viral proteins, antimicrobial compounds and drugs, and the underlying structure of the stratum corneum. In this paper we review these techniques and provide examples of the systems that have been examined. We finish with a future outlook on the use of these techniques to improve our understanding of the interactions of membranes with biomolecules.

中文翻译：

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使用中子和 X 射线衍射研究双层膜堆叠的分子相互作用

根据中子和 X 射线衍射数据重建层状晶胞，提供有关分子和分子片段相对于双层的配置和位置的信息。当辅以分子氘化的明智使用时，该技术可探测构成晶体晶胞的双层膜和水层内的分子相互作用和构象。该视角与模型无关，并且可能具有比其他技术更高的分辨率。在中子衍射的情况下，测量包括在水层对比度变化的条件下仔细归一化的衍射强度。随后使用来自峰值强度随对比度变化的相位信息来进行晶胞的傅立叶重建。尽管相位问题对于相应的 X 射线测量来说并不容易解决，但直观的方法通常就足够了。在这里，我们讨论作为双层散射长度密度分布探针的两种互补技术，以及这种视角如何提供有关脂质双层内或之间的分子位置和方向的信息。例如，在层状相的基本范式中，该方法提供了对冷冻保护剂和应激蛋白的位置和相互作用、病毒蛋白、抗菌化合物和药物的作用机制以及角质层的基础结构的详细见解。 。在本文中，我们回顾了这些技术并提供了已检查的系统的示例。最后，我们对使用这些技术来提高我们对膜与生物分子相互作用的理解进行了展望。