@article{3906,
  keywords = {Escherichia coli, Membrane Proteins, Models, Molecular, Protein Conformation, Escherichia coli Proteins, Cell Membrane, Cryoelectron Microscopy, Liposomes, Multidrug Resistance-Associated Proteins},
  author = {Xia Yao and Xiao Fan and Nieng Yan},
  title = {Cryo-EM analysis of a membrane protein embedded in the liposome.},
  abstract = { <p>Membrane proteins (MPs) used to be the most difficult targets for structural biology when X-ray crystallography was the mainstream approach. With the resolution revolution of single-particle electron cryo-microscopy (cryo-EM), rapid progress has been made for structural elucidation of isolated MPs. The next challenge is to preserve the electrochemical gradients and membrane curvature for a comprehensive structural elucidation of MPs that rely on these chemical and physical properties for their biological functions. Toward this goal, here we present a convenient workflow for cryo-EM structural analysis of MPs embedded in liposomes, using the well-characterized AcrB as a prototype. Combining optimized proteoliposome isolation, cryo-sample preparation on graphene grids, and an efficient particle selection strategy, the three-dimensional (3D) reconstruction of AcrB embedded in liposomes was obtained at 3.9 {\r A} resolution. The conformation of the homotrimeric AcrB remains the same when the surrounding membranes display different curvatures. Our approach, which can be widely applied to cryo-EM analysis of MPs with distinctive soluble domains, lays out the foundation for cryo-EM analysis of integral or peripheral MPs whose functions are affected by transmembrane electrochemical gradients or/and membrane curvatures.</p> },
  year = {2020},
  journal = {Proc Natl Acad Sci U S A},
  volume = {117},
  pages = {18497-18503},
  month = {2020 Aug 04},
  issn = {1091-6490},
  doi = {10.1073/pnas.2009385117},
  language = {eng},
}