Channel activity of OmpF monitored in nano-BLMs
Eva K. Schmitt 1, Maarten Vrouenraets 2 and Claudia Steinem 1*
1 University of Regensburg
2 Biomade Technology Foundation
* To whom correspondence should be addressed. E-mail: claudia.steinem{at}chemie.uni-regensburg.de.
Submitted on February 18, 2006
Revised on March 29, 2006
Accepted on 5 June 2006
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Abstract |
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Free-standing lipid bilayer membranes can be formed on small apertures (60 nm diameter) on highly ordered porous alumina substrates. The formation process of the membranes on a 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol sub-monolayer was followed by impedance spectroscopy. After lipid bilayers had thinned, the reconstitution and ionic conducting properties of the outer membrane protein OmpF of E. coli were monitored using single channel recordings. The characteristic conductance states of the three monomers, fast kinetics and subconductance states were observed. The blockade of the ion flow due to the interaction of the antibiotic ampicillin with the protein was verified indicating the full functionality of the protein channel in nanometer-scale bilayer membranes.
Key Words:
fast kinetics, impedance spectroscopy, lipid bilayer, porous alumina, subconductance states
