Structural study of the membrane protein MscL using cell-free expression and solid-state NMR

J Magn Reson. 2010 May;204(1):155-9. doi: 10.1016/j.jmr.2010.02.003. Epub 2010 Feb 11.


High-resolution structures of membrane proteins have so far been obtained mostly by X-ray crystallography, on samples where the protein is surrounded by detergent. Recent developments of solid-state NMR have opened the way to a new approach for the study of integral membrane proteins inside a membrane. At the same time, the extension of cell-free expression to the production of membrane proteins allows for the production of proteins tailor made for NMR. We present here an in situ solid-state NMR study of a membrane protein selectively labeled through the use of cell-free expression. The sample consists of MscL (mechano-sensitive channel of large conductance), a 75kDa pentameric alpha-helical ion channel from Escherichia coli, reconstituted in a hydrated lipid bilayer. Compared to a uniformly labeled protein sample, the spectral crowding is greatly reduced in the cell-free expressed protein sample. This approach may be a decisive step required for spectral assignment and structure determination of membrane proteins by solid-state NMR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell-Free System / chemistry*
  • Computer Simulation
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / ultrastructure*
  • Ion Channels / chemistry*
  • Ion Channels / ultrastructure*
  • Magnetic Resonance Spectroscopy / methods
  • Membrane Proteins / chemistry*
  • Membrane Proteins / ultrastructure*
  • Models, Chemical*
  • Models, Molecular*
  • Powders


  • Escherichia coli Proteins
  • Ion Channels
  • Membrane Proteins
  • MscL protein, E coli
  • Powders