AtpE

AtpE is a gene that encodes the Fo subunit c of the F-type ATP synthase complex in many bacteria and chloroplasts. In Escherichia coli and many other bacteria, AtpE corresponds to the c subunit of the membrane-embedded Fo region that forms a rotary ring during proton translocation.

The protein product is small and highly hydrophobic, typically around 70–100 amino acids in length, and contains two transmembrane helices. Multiple copies of the c-subunit assemble to form the c-ring, which interacts with the a-subunit and the central stalk of the F1 portion. Protons moving across the membrane drive rotation of the c-ring, which in turn drives conformational changes in the F1 sector to synthesize ATP from ADP and inorganic phosphate.

Genetically, atpE is usually located in the ATP synthase operon (the atp operon) and is coexpressed with other atp genes encoding the various Fo and F1 subunits. The c-subunit stoichiometry of the c-ring varies among organisms, influencing the number of protons required per ATP synthesized.

Medical and scientific relevance includes the antibiotic bedaquiline, which targets the Fo c-subunit to inhibit ATP synthesis in Mycobacterium tuberculosis. Mutations in atpE can confer resistance to bedaquiline in some strains, highlighting the gene’s role in drug sensitivity and energy metabolism.

Overall, AtpE is essential for the rotary mechanism of oxidative phosphorylation in many bacteria, contributing to the coupling of proton motive force to ATP production.