2021/11/25 by F. Kolbe, Schara Safarian, Ż. Piórek +3 · 1 citation
Biochemistry, Genetics and Molecular Biology · #Photosynthetic Processes and Mechanisms #Advanced Electron Microscopy Techniques and Applications #Advanced Fluorescence Microscopy Techniques
paper · doi:10.1038/s41467-021-27174-y
openalex publication_date 2021/11/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
Cytochrome c oxidases are among the most important and fundamental enzymes of life. Integrated into membranes they use four electrons from cytochrome c molecules to reduce molecular oxygen (dioxygen) to water. Their catalytic cycle has been considered to start with the oxidized form. Subsequent electron transfers lead to the E-state, the R-state (which binds oxygen), the P-state (with an already split dioxygen bond), the F-state and the O-state again. Here, we determined structures of up to 1.9 Å resolution of these intermediates by single particle cryo-EM. Our results suggest that in the O-state the active site contains a peroxide dianion and in the P-state possibly an intact dioxygen molecule, the F-state may contain a superoxide anion. Thus, the enzyme's catalytic cycle may have to be turned by 180 degrees.