Abstract
Cable bacteria contain electron-transport pathways that are among the longest found in living systems, reaching the centimeter scale. These bacteria have very high electrical conductivities, and the electron- transport mechanism is poorly understood. We performed theoretical analysis to assess possible transport mechanisms in cable bacteria. While earlier studies suggested that extended carrier delocalization or the formation of large polarons might explain the measured conductivities, we find that vibronically coupled multi-step hopping appears to dictate the biological electron transport mechanisms on these very large length scale.