Possible Proton Transfer Pathways in Membrane Proteins

Possible Proton Transfer Pathways in Membrane Proteins 

One of the most important findings of investigations on the reaction mechanism of cytochrome c oxidase is the discovery of its proton pumping 

In the X-ray structure of bovine heart cytochrome c oxidase in the fully oxidized state at 2.8 resolution, two hydrogen bond networks connecting the molecular surface on the matrix side to that on the intermembrane surface were identified (Tsukihara et ah, 1996). Both networks contain possible hydrogen bond structures, as defined by the criteria stated above, but do not include elements of structure comprising the O2 reduction site. However, small conformational changes induced by changes in the redox 

Wikstr m and his coworkers that proton pumping is coupled only to the transfer of the latter two of the four electrons that are required for complete reduetion of an O2 to two water molecules (Wikstr m and Morgan, 1992). The finding was reexamined by another group in detail (Michel, 1999) to yield somewhat different interpretation for the experimental results. 

A Redox Coupled Conformational Change in Cytochrome c Oxidase 

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