Cytochrome c Oxidase
This page shows some interactive JSmol views of Cytochrome c Oxidase.
The first figure shows the dimeric structure of (bovine) cytochrome c oxidase. This one takes a little while to load.
This is a very large, membrane-bound protein. The vertical α-helices normally lie in the mitochondrial membrane
(outer side of the membrane at the top).
There are a lot of long chain additives (glycerols, detergents ...) included the structure - these help to preserve
the structure intact when it is isolated from the membrane. The red spheres are water molecules.
The second figure shows a monomer with the protein chains shown as strands.
Zoom in to see the positioning of the metal active sites.
Cytochrome c can dock with the protein on the outside of the mitochondrial membrane (top of the picture).
The third figure shows the active sites (in the oxidixed form) with the protein chains removed.
Note that they are quite close to each other (why?).
The next view shows the active site in the reduced form of the same protein, compare with the oxidised form
- which sites change and which do not? What clues does this give for their functions?
The last set of views focus on the individual metal centres; heme a, CuA, and heme a3/CuB taken from the reduced resting state structure as well as the oxidised form of heme a3/CuB. (Note: there is some uncertainty regarding the nature of the bridging species in heme a3/CuB)
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