Our study just published in Nature Communication show that long range conduction of cable bacteria is all in the chemical structure and electron transport mechanism of periplasmic bacterial wires.
We combined high-resolution microscopy, spectroscopy, and chemical imaging on individual cable bacterium filaments and 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 suggests a hitherto unknown form of electron transport that enables efficient conduction in centimeter-long protein structures.
The nano-IR of the cables was tricky (and rewarding) to obtain, and I am amazed of the structures and capabilities of these bacteria.
Thanks lots to Eric for compiling all our data and leading the efforts. Is has been a highly inspirational journey.