FIG 6 .
Summary of reduction potentials tested and general model for inner membrane electron transfer pathways. Reduction potentials versus standard hydrogen electrode (SHE) for all metal oxides, chelates, and electrodes tested as electron acceptors for wild-type and ΔimcH::Kanr strains in this study. Due to the heterogeneity of metal oxides, a range of potentials from previously reported values are shown. Reduction of the electron acceptor by a given strain is indicated as “+,” whereas lack of reduction is indicated as “−.” According to this model, cells typically route electron flux out of the quinone pool via an ImcH-dependent pathway for reduction of high-potential acceptors, while an as yet undiscovered pathway is used for low-potential acceptors.