Combined 1H-Detected Solid-State NMR Spectroscopy and Electron Cryotomography to Study Membrane Proteins across Resolutions in Native Environments

• Published in: Structure (London) 2018-01, Vol.26 (1), p.161-170.e3
• Main Authors: Baker, Lindsay A., Sinnige, Tessa, Schellenberger, Pascale, de Keyzer, Jeanine, Siebert, C. Alistair, Driessen, Arnold J.M., Baldus, Marc, Grünewald, Kay
• Format: Article
• Language: English
• Subjects: electron cryotomography; hybrid methods; MAS; membrane proteins; native membranes; solid-state NMR; YidC
• ISSN: 0969-2126; 1878-4186
• DOI: 10.1016/j.str.2017.11.011

Membrane proteins remain challenging targets for structural biology, despite much effort, as their native environment is heterogeneous and complex. Most methods rely on detergents to extract membrane proteins from their native environment, but this removal can significantly alter the structure and function of these proteins. Here, we overcome these challenges with a hybrid method to study membrane proteins in their native membranes, combining high-resolution solid-state nuclear magnetic resonance spectroscopy and electron cryotomography using the same sample. Our method allows the structure and function of membrane proteins to be studied in their native environments, across different spatial and temporal resolutions, and the combination is more powerful than each technique individually. We use the method to demonstrate that the bacterial membrane protein YidC adopts a different conformation in native membranes and that substrate binding to YidC in these native membranes differs from purified and reconstituted systems. [Display omitted] •CryoET and ssNMR give complementary information about proteins in native membranes•One sample can be prepared for both methods without the use of detergents•Hybrid method shows differences between purified and native preparations of YidC•Sample preparation reduces costs and time and suggests new strategy for assignment Membrane proteins are often treated with detergents, which can affect structure and activity. Baker et al. apply a hybrid method to bacterial membrane proteins in native membranes without detergent, using solid-state NMR spectroscopy and electron cryotomography. They find that the structure and function of YidC differ with and without detergent.