The dimerization equilibrium of a ClC Cl-/H+ antiporter in lipid bilayers
The dimerization equilibrium of a ClC Cl-/H+ antiporter in lipid bilayers
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DOI：
10.7554/elife.17438
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发表时间：
2016-08-03
期刊：
影响因子：
7.7
通讯作者：
Robertson, Janice L.
中科院分区：
文献类型：
--
作者：
Chadda, Rahul;Krishnamani, Venkatramanan;Robertson, Janice L.
脂质双层中膜蛋白界面之间的相互作用在膜蛋白折叠中起着重要作用，但这些相互作用的强度的量化一直具有挑战性。研究ClC型转运蛋白的二聚化提供了解决该问题的新方法，因为单个亚基采用稳定且功能可验证的折叠，将系统限制为两种状态-单体或二聚体。在这里，我们使用单分子光漂白分析，以测量的概率ClC-ec 1亚基捕获到脂质体在挤出过程中的大，多层膜。捕获统计描述了单体到二聚体的转变，其依赖于亚基/脂质摩尔分数密度并且遵循平衡二聚化等温线。这允许测量的自由能ClC-ec 1二聚在脂质双层，揭示了它是迄今为止测量的最强的膜蛋白复合物之一，并介绍了它作为新型的二聚模型，以调查的物理力量，驱动膜蛋白协会在膜。
Interactions between membrane protein interfaces in lipid bilayers play an important role in membrane protein folding but quantification of the strength of these interactions has been challenging. Studying dimerization of ClC-type transporters offers a new approach to the problem, as individual subunits adopt a stable and functionally verifiable fold that constrains the system to two states - monomer or dimer. Here, we use single-molecule photobleaching analysis to measure the probability of ClC-ec1 subunit capture into liposomes during extrusion of large, multilamellar membranes. The capture statistics describe a monomer to dimer transition that is dependent on the subunit/lipid mole fraction density and follows an equilibrium dimerization isotherm. This allows for the measurement of the free energy of ClC-ec1 dimerization in lipid bilayers, revealing that it is one of the strongest membrane protein complexes measured so far, and introduces it as new type of dimerization model to investigate the physical forces that drive membrane protein association in membranes.