by Keyword: Electrons
Lozano, H, Millan-Solsona, R, Blanco-Cabra, N, Fabregas, R, Torrents, E, Gomila, G, (2021). Electrical properties of outer membrane extensions from Shewanella oneidensis MR-1 Nanoscale 13, 18754-18762 
Outer membrane extensions from the metal-reducing bacterium Shewanella oneidensis MR-1 show an insulating behavior in dry air environment as measured by scanning dielectric microscopy.
JTD Keywords: constant, dielectric polarization, microbial nanowires, nanoscale, transport, Air environment, Bacteria, Bacterial cells, Bacterial nanowires, Dry air, Electron transport, Electrons, Metal-reducing bacteria, Outer membrane, Periplasm, Phase-minerals, Proteins, Shewanella, Shewanella oneidensis mr-1, Solid phasis, Solid-phase, Space division multiple access, Tubulars
Boschker, HTS, Cook, PLM, Polerecky, L, Eachambadi, RT, Lozano, H, Hidalgo-Martinez, S, Khalenkow, D, Spampinato, V, Claes, N, Kundu, P, Wang, D, Bals, S, Sand, KK, Cavezza, F, Hauffman, T, Bjerg, JT, Skirtach, AG, Kochan, K, McKee, M, Wood, B, Bedolla, D, Gianoncelli, A, Geerlings, NMJ, Van Gerven, N, Remaut, H, Geelhoed, JS, Millan-Solsona, R, Fumagalli, L, Nielsen, LP, Franquet, A, Manca, JV, Gomila, G, Meysman, FJR, (2021). Efficient long-range conduction in cable bacteria through nickel protein wires Nature Communications 12, 3996
Filamentous cable bacteria display 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 protein 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. Filamentous cable bacteria conduct electrical currents over centimeter distances through fibers embedded in their cell envelope. Here, Boschker et al. show that the fibers consist of a conductive core containing nickel proteins that is surrounded by an insulating protein shell.
JTD Keywords: Bacteria (microorganisms), Bacterial protein, Bacterial proteins, Bacterium, Chemistry, Deltaproteobacteria, Electric conductivity, Electricity, Electron, Electron transport, Metabolism, Microscopy, Nanowires, Nickel, Physiology, Protein, Resonance raman, Spectroscopy, Transport electrons
