FIG 2.

Expression of 3-nm-diameter electrically conductive filaments in the strain PCA/ΔPilB. (a) Transmission electron micrograph of a negatively stained cell. (b) Atomic force microscopy, noncontact topographical imaging with deflection output of a single filament, harvested from cells, laying on highly oriented pyrolytic graphite. (c) Height of the filament at the white line cross-section shown on the filament with the height profile shown in the inset. (d) Point mode IV spectroscopy of the individual G. sulfurreducens strain PCA/ΔPilB filaments shown in red overlaid with wild-type G. sulfurreducens in blue and G. sulfurreducens strain Aro-5 (in which the native PilA gene is replaced with a synthetic pilin gene designed to yield poorly conductive pili) in black. Data for pili from wild-type and strain Aro-5 are from reference 44.