Efficient long-range conduction in cable bacteria through nickel protein wires

Boschker, H. T. S.; Cook, P. L. M.; Polerecky, L.; Thiruvallur Eachambadi, R.; Lozano, H.; Hidalgo-Martinez, S.; Khalenkow, D.; Spampinato, V.; Claes, N.; Kundu, P.; Wang, D.; Bals, S.; Sand, K. K.; Cavezza, F.; Hauffman, T.; Tataru Bjerg, J.; Skirtach, A. G.; Kochan, K.; McKee, M.; Wood, B.; Bedolla, D.; Gianoncelli, A.; Geerlings, N. M. J.; Van Gerven, N.; Remaut, H.; Geelhoed, J. S.; Millan-Solsona, R.; Fumagalli, L.; Nielsen, L.-P.; Franquet, A.; Manca, J. V.; Gomila, G.; Meysman, F. J. R.

doi:10.1101/2020.10.23.351973

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bioRxiv · 10.1101/2020.10.23.351973

Efficient long-range conduction in cable bacteria through nickel protein wires

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Abstract

Filamentous cable bacteria display unrivalled long-range electron transport, generating electrical currents over centimeter distances through a highly ordered network of fibers embedded in their cell envelope. The conductivity of these periplasmic wires is exceptionally high for a biological material, but their chemical structure and underlying electron transport mechanism remain unresolved. Here, we combine high-resolution microscopy, spectroscopy, and chemical imaging on individual cable bacterium filaments to demonstrate that the periplasmic wires consist of a conductive protein core surrounded by an insulating shell layer. The core proteins contain a sulfur-ligated nickel cofactor, and conductivity decreases when nickel is oxidized or selectively removed. The involvement of nickel as the active metal in biological conduction is remarkable, and suggests a hitherto unknown form of electron transport that enables efficient conduction in centimeter-long protein structures.

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Boschker, H. T. S., Cook, P. L. M., Polerecky, L., Thiruvallur Eachambadi, R., Lozano, H., Hidalgo-Martinez, S., Khalenkow, D., Spampinato, V., Claes, N., Kundu, P., Wang, D., Bals, S., Sand, K. K., Cavezza, F., Hauffman, T., Tataru Bjerg, J., Skirtach, A. G., Kochan, K., McKee, M., Wood, B., Bedolla, D., Gianoncelli, A., Geerlings, N. M. J., Van Gerven, N., Remaut, H., Geelhoed, J. S., Millan-Solsona, R., Fumagalli, L., Nielsen, L.-P., Franquet, A., Manca, J. V., Gomila, G., Meysman, F. J. R.. 2020-10-23. Efficient long-range conduction in cable bacteria through nickel protein wires. https://doi.org/10.1101/2020.10.23.351973

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