Membrane protein crystallization in lipidic mesophases. A mechanism study using X-ray microdiffraction
Membrane protein crystallization in lipidic mesophases. A mechanism study using X-ray microdiffraction
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DOI：
10.1039/b618173b
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发表时间：
2007-01-01
影响因子：
3.4
通讯作者：
Caffrey, Martin
中科院分区：
文献类型：
--
作者：
Cherezov, Vadim;Caffrey, Martin
膜结构生物学家试图了解膜蛋白如何在分子水平上发挥作用。实现这一目标的最直接的方法之一是了解蛋白质的结构，最好是原子分辨率。迄今为止，这只能通过大分子晶体学的方法来完成。该方法的组成部分是需要衍射质量的三维晶体，并且它们的生产代表了结构测定的整个过程中的主要限速步骤。内消旋法是一种新型的膜蛋白结晶方法。它利用了介晶中间相，特别是立方相。已经提出了该方法如何工作的机制。在这项研究中，我们着手测试假设的一个方面，即蛋白质从散装中间相水库迁移到晶体的表面的层状管道的方式。使用亚微米大小的X射线束之间的界面生长的膜蛋白质晶体和散装立方相的微米空间分辨率询问。正如预期的那样，在界面处观察到来自层状相的特征衍射。这一结果支持了蛋白质从本体中间相向上进入晶体表面的过程中使用层状门户的提议。
The membrane structural biologist seeks to understand how membrane proteins function at a molecular level. One of the most direct ways of accomplishing this requires knowing the structure of the protein, ideally at atomic resolution. To date, this can only be done by the method of macromolecular crystallography. Integral to the method is the need for three-dimensional crystals of diffraction quality and their production represents a major rate-limiting step in the overall process of structure determination. The in meso method is a novel approach for crystallizing membrane proteins. It makes use of lipidic mesophases, the cubic phase in particular. A mechanism for how the method works has been proposed. In this study, we set out to test one aspect of the hypothesis which posits that the protein migrates from the bulk mesophase reservoir to the face of the crystal by way of a lamellar conduit. Using a sub-micrometer-sized X-ray beam the interface between a growing membrane protein crystal and the bulk cubic phase was interrogated with micrometer spatial resolution. Characteristic diffraction from the lamellar phase was observed at the interface as expected. This result supports the proposal that the protein uses a lamellar portal on its way from the bulk mesophase up and into the face of the crystal.