Information on Cytochrome C Oxidase

Cytochrome C oxidase is also known as Complex IV in the electron transport chain.  It transfers electrons and protons from reduced cytochrome C and conserves the free energy released by creating a proton gradient which is then used to drive the synthesis of ATP.  This is a metalloprotein that is in a superfamily of heme-copper containing proteins.  This protein is the final step in mitochondrial respiratory which is the principle energy-generating system for cells!  There are 5 metals located in the active site of cytochrome C oxidase which does redox chemistry with cytochrome C to gain electrons to transport to the inner membrane.  This protein can take O₂ and create water by adding protons yet makes sure the electrons get to the inner membrane so that ATP can be generated.  Without Cytochrome C oxidase the whole energy-transducing process is shut down which means no energy would be produced. 

 http://link.springer.com/article/10.1023%2FA%3A1022638013825?LI=true

As I mentioned before there is a redox reaction happening.  This redox reaction is actually regulated by a conformational shift within a histidine and an aspartic acid which is located right next to the active site which helps in opening and closing the active site from regulation.  This conformational change is like a T and R state of hemoglobin but just as important. The histidine is important in redox control of proton collecting as it is part of the D pathway. 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1876541/

 There are also 2 heme groups within Cytochrome C oxidase.  These hemes help drive the active proton transport from the interior across the enzyme via a water channel to the waiting O­₂ molecule to form water.  This is via the D pathway which just refers to the proton and O₂ coming together to form water.  There are so many things going on in this protein it is incredible.  The heme gets oxidized and arg-38 opens up to the water channel.  When the heme is reduced the asp-51 is opened to the intermembrane space which then releases the proton into the space and returns to its position away from the intermembrane.  This is how we get energy!  Without this process our main way to get energy into a usable form is impossible.    

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC307562/

  

Also, who doesn’t love a protein that can be studied via NMR?

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3145682/