Biosystems Science and Engineering (BSSE), ETH Zürich, Mattenstrasse 26, 4058 Basel, Switzerland.
ACS Nano. 2012 Jan 24;6(1):961-71. doi: 10.1021/nn204624p. Epub 2011 Dec 30.
Single-molecule force spectroscopy (SMFS) can quantify and localize inter- and intramolecular interactions that determine the folding, stability, and functional state of membrane proteins. To conduct SMFS the membranes embedding the membrane proteins must be imaged and localized in a rather time-consuming manner. Toward simplifying the investigation of membrane proteins by SMFS, we reconstituted the light-driven proton pump bacteriorhodopsin into lipid nanodiscs. The advantage of using nanodiscs is that membrane proteins can be handled like water-soluble proteins and characterized with similar ease. SMFS characterization of bacteriorhodopsin in native purple membranes and in nanodiscs reveals no significant alterations of structure, function, unfolding intermediates, and strengths of inter- and intramolecular interactions. This demonstrates that lipid nanodiscs provide a unique approach for in vitro studies of native membrane proteins using SMFS and open an avenue to characterize membrane proteins by a wide variety of SMFS approaches that have been established on water-soluble proteins.
单分子力谱（SMFS）可以定量和定位决定膜蛋白折叠、稳定性和功能状态的分子间和分子内相互作用。为了进行 SMFS，必须以相当耗时的方式对嵌入膜蛋白的膜进行成像和定位。为了简化 SMFS 对膜蛋白的研究，我们将光驱动质子泵菌视紫质重构成脂质纳米盘。使用纳米盘的优势在于可以像处理水溶性蛋白质一样处理膜蛋白，并同样轻松地对其进行表征。SMFS 对天然紫色膜和纳米盘中菌视紫质的表征表明，结构、功能、展开中间体以及分子间和分子内相互作用的强度没有明显改变。这表明脂质纳米盘为使用 SMFS 对天然膜蛋白进行体外研究提供了一种独特的方法，并为通过已在水溶性蛋白质上建立的各种 SMFS 方法来表征膜蛋白开辟了一条途径。
