by Keyword: Electricity

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,

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

Cuervo, A., Dans, P. D., Carrascosa, J. L., Orozco, M., Gomila, G., Fumagalli, L., (2014). Direct measurement of the dielectric polarization properties of DNA Proceedings of the National Academy of Sciences of the United States of America 111, (35), E3624-E3630

The electric polarizability of DNA, represented by the dielectric constant, is a key intrinsic property that modulates DNA interaction with effector proteins. Surprisingly, it has so far remained unknown owing to the lack of experimental tools able to access it. Here, we experimentally resolved it by detecting the ultraweak polarization forces of DNA inside single T7 bacteriophages particles using electrostatic force microscopy. In contrast to the common assumption of low-polarizable behavior like proteins (εr ~ 2–4), we found that the DNA dielectric constant is ~ 8, considerably higher than the value of ~ 3 found for capsid proteins. State-of-the-art molecular dynamic simulations confirm the experimental findings, which result in sensibly decreased DNA interaction free energy than normally predicted by Poisson–Boltzmann methods. Our findings reveal a property at the basis of DNA structure and functions that is needed for realistic theoretical descriptions, and illustrate the synergetic power of scanning probe microscopy and theoretical computation techniques.

JTD Keywords: Atomic force microscopy, Atomistic simulations, DNA packaging, DNA-ligand binding, Poisson-Boltzmann equation, capsid protein, DNA, double stranded DNA, amino acid composition, article, atomic force microscopy, bacteriophage, bacteriophage T7, dielectric constant, dipole, DNA binding, DNA packaging, DNA structure, electron microscopy, ligand binding, nonhuman, polarization, priority journal, protein analysis, protein DNA interaction, scanning probe microscopy, static electricity, virion, virus capsid, virus particle, atomic force microscopy, atomistic simulations, DNA packaging, DNA-ligand binding, Poisson-Boltzmann equation, Bacteriophage T7, Capsid, Cations, Dielectric Spectroscopy, DNA, DNA, Viral, DNA-Binding Proteins, Electrochemical Techniques, Ligands, Microscopy, Atomic Force, Models, Chemical, Nuclear Proteins