Simultaneous measurement of ionic current and fluorescence from single protein pores

J Am Chem Soc. 2009 Feb 11;131(5):1652-3. doi: 10.1021/ja808128s.


The ability to simultaneously monitor both the ionic current and fluorescence from membrane channels and pores has the potential to link structural changes with function in such proteins. We present a new method for simultaneously measuring single-channel electrical currents and fluorescence from membrane proteins by using water-in-oil droplet bilayers. We demonstrate the simultaneous fluorescence and electrical detection of stochastic blocking by cyclodextrin in multiple staphylococcal alpha-hemolysin pores. The combined fluorescence signal from individual pores exhibits the same sequence of blocking events as the total current recording, showing that the two signals from each pore are correlated.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Toxins / chemistry*
  • Bacterial Toxins / metabolism
  • Electrodes
  • Hemolysin Proteins / chemistry*
  • Hemolysin Proteins / metabolism
  • Hydrogels / chemistry
  • Ion Channels / chemistry*
  • Ion Channels / metabolism
  • Lipid Bilayers / chemistry*
  • Lipid Bilayers / metabolism
  • Microscopy, Fluorescence
  • Phosphatidylcholines / chemistry
  • Stochastic Processes
  • beta-Cyclodextrins / chemistry*
  • beta-Cyclodextrins / metabolism


  • Bacterial Toxins
  • Hemolysin Proteins
  • Hydrogels
  • Ion Channels
  • Lipid Bilayers
  • Phosphatidylcholines
  • beta-Cyclodextrins
  • staphylococcal alpha-toxin
  • heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin
  • 1,2-diphytanoylphosphatidylcholine