Helicity, membrane incorporation, orientation and thermal stability of the large conductance mechanosensitive ion channel from E. coli

Isaiah T. Arkin, Sergei I. Sukharev, Paul Blount, Ching Kung, Axel T. Brünger

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In this report, we present studies on the large conductance mechanosensitive ion channel (MscL) from E. coli in detergent micelles and lipid vesicle. Both transmission Fourier transform infrared spectroscopy and circular dichroism (CD) spectra indicate that the protein is highly helical in detergent as well as liposomes. The secondary structure of the proteins was shown to be highly resistant towards denaturation (25-95°C) based on an ellipticity thermal profile. Amide H+/D+ exchange was shown to be extensive (ca. 66%), implying that two thirds of the protein are water accessible. MscL, reconstituted in oriental lipid bilayers, was shown to possess a net bilayer orientation using dichroic ratios measured by attenuated total- reflection Fourier transform infrared spectroscopy. Here, we present and discuss this initial set of structural data on this new family of ion- channel proteins.

Original languageEnglish (US)
Pages (from-to)131-140
Number of pages10
JournalBiochimica et Biophysica Acta - Biomembranes
Issue number1
StatePublished - Feb 2 1998



  • Circular dichroism
  • Fourier transform infrared spectroscopy (FT-IR)
  • Ion channel
  • Lipid bilayer
  • Membrane protein

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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