Abstract:
Membrane proteins reside at interfaces between aqueous and lipid media and solving their molecular structure relies most of the time on removing them from the membrane using detergent. Luckily, this solubilization process does not strip them from all the associated lipids and single-particle cryo-transmission electron microscopy (SP-TEM) has proved a very good tool to visualise both protein high-resolution structure and, often, many of its associated lipids. In this review, we observe membrane protein structures from the Protein DataBank and their associated maps in the Electron Microscopy DataBase and determine how the SP-TEM maps allow lipid visualization, the type of binding sites, the influence of symmetry, resolution and other factors. We illustrate lipid visualization around and inside the protein core, show that some lipid bilayers in the core can be shifted with respect to the membrane and how some proteins can actively bend the lipid bilayer that binds to them. We conclude that resolution improvement in SP-TEM will likely enable many more discoveries regarding the role of lipids bound to proteins.
摘要:
膜蛋白存在于水性介质和脂质介质之间的界面处,并且溶解它们的分子结构大部分时间依赖于使用洗涤剂将它们从膜中除去。幸运的是,这种溶解过程不会将它们从所有相关的脂质中剥离出来,单粒子低温透射电子显微镜(SP-TEM)已被证明是可视化蛋白质高分辨率结构和蛋白质的非常好的工具,经常,它的许多相关脂质。在这次审查中,我们观察蛋白质数据库中的膜蛋白结构及其在电子显微镜数据库中的相关图,并确定SP-TEM图如何允许脂质可视化,结合位点的类型,对称性的影响,分辨率和其他因素。我们说明了蛋白质核心周围和内部的脂质可视化,显示核心中的一些脂质双层可以相对于膜移动,以及一些蛋白质如何主动弯曲与它们结合的脂质双层。我们得出的结论是,SP-TEM分辨率的提高可能会使有关脂质与蛋白质结合的作用的更多发现。