Figure 2

Conservation of the energy metabolism pathways of Geobacter sulfurreducens. Shown are the pathways for acetate activation and oxidation via the TCA cycle in the cytoplasm; inner membrane oxidation of TCA cycle products coupled with electron/proton transport and ATP generation; and periplasmic and outer membrane cytochromes known to be required in vivo for transfer of electrons to an extracellular acceptor. The genes encoding the enzymes of these pathways and their full conservation pattern across all of the Geobacter genomes are listed in Additional file 6 of the supplementary material. The enzymes are colored black if there were orthologs for every subunit in all of the species and red if there were not. OmcB is shown in gray because there positional but not sequence-based orthologs (see text and figure 5).