How does cytochrome oxidase pump protons?

How does cytochrome oxidase pump protons?

We are now in an exciting era of molecular bioenergetics. High-resolution x-ray structures have been determined for several of the key components of bioenergetics systems, including the respiratory enzymes cytochrome oxidase (1–4) and the bc1 complex (5, 6), the F1 component of the F1Fo-ATPase (7), the light-driven proton pump bacteriorhodopsin (8, 9), and the bacterial photosynthetic reaction ...

The proton pump of cytochrome oxidase.

Accessibility of the cytochrome a heme in cytochrome c oxidase to exchangeable protons.

The comparison of the resonance Raman spectrum of cytochrome a2+ from cytochrome oxidase in deuterated buffers to that in protonated buffers reveals many lines that have different frequency or intensity. Some of the frequency differences are very large, e.g. on the order of 10 cm-1. From these differences in the Raman spectra, we infer that the heme pocket is readily accessible to protons and t...

Kinetic gating of the proton pump in cytochrome c oxidase.

Cytochrome c oxidase (CcO), the terminal enzyme of the respiratory chain, reduces oxygen to water and uses the released energy to pump protons across a membrane. Here, we use kinetic master equations to explore the energetic and kinetic control of proton pumping in CcO. We construct models consistent with thermodynamic principles, the structure of CcO, experimentally known proton affinities, an...

Initiation of the proton pump of cytochrome c oxidase.

Cytochrome c oxidase is the terminal enzyme of the respiratory chain that is responsible for biological energy conversion in mitochondria and aerobic bacteria. The membrane-bound enzyme converts free energy from oxygen reduction to an electrochemical proton gradient by functioning as a redox-coupled proton pump. Although the 3D structure and functional studies have revealed proton conducting pa...