Electrochemical Characterization of the Periplasmic PpcA <i>c‐</i>Cytochrome of <i>Geobacter sulfurreducens</i> Reveals Its Affinity for Uranium

Abstract Geobacter bacteria produce conductive pili appendages and an outer membrane‐anchored lipopolysaccharide to immobilize uranium extracellularly. Yet, some radionuclide enters the cell envelope, where is rapidly mineralized by periplasmic c ‐cytochromes. To investigate this reaction, we constructed envelope biomimetic interfaces containing PpcA, most conserved abundant ‐cytochrome in species. Cyclic voltammograms revealed much higher rate constants for than iron, natural electron acceptor of , independently metal‐ligand complexation. These results are consistent with a affinity PpcA providing plausible explanation rapid mineralization inside envelope. The studies highlight value electrochemical dissect contribution cytochromes metal reduction identify redox‐active proteins needed sensory applications.