• Open Access

The Effect of Bacterial Signal Indole on the Electrical Properties of Lipid Membranes

Authors

  • Catalin Chimerel,

    1. Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom), Fax: (+44) (0)1223 337000
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  • Dr. Andrew J. Murray,

    1. Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG (United Kingdom)
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  • Enno R. Oldewurtel,

    1. Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom), Fax: (+44) (0)1223 337000
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  • Dr. David K. Summers,

    1. Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH (United Kingdom)
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  • Dr. Ulrich F. Keyser

    Corresponding author
    1. Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom), Fax: (+44) (0)1223 337000
    • Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE (United Kingdom), Fax: (+44) (0)1223 337000
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Abstract

Indole is an important biological signalling molecule produced by many Gram positive and Gram negative bacterial species, including Escherichia coli. Here we study the effect of indole on the electrical properties of lipid membranes. Using electrophysiology, we show that two indole molecules act cooperatively to transport charge across the hydrophobic core of the lipid membrane. To enhance charge transport, induced by indole across the lipid membrane, we use an indole derivative, 4 fluoro-indole. We demonstrate parallels between charge transport through artificial lipid membranes and the function of complex eukaryotic membrane systems by showing that physiological indole concentrations increase the rate of mitochondrial oxygen consumption. Our data provide a biophysical explanation for how indole may link the metabolism of bacterial and eukaryotic cells.

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