Stuchebrukhov research group           Department of Chemistry           University of California at Davis

The Main Conclusions

* His291 is a probable pump element in CcO

* Kinetic gating mechanism: ET Fast PT (pumping H+) Slow PT (chemical H+)

* Proton pumping path involves: Glu242 PRDa3/Arg438 His291

* 1e /1H+ pumping stoichiometry

* Lys171B /Asp173B is a likely proton exit site

* Absence of proton leaking is due to energy profile in exit proton channel

A stepwise electron transfer from CuA to binuclear center is coupled to proton translocation from Glu242 to His291. [Popovic, Quenneville, Stuchebrukhov, JPC B, 109, 3616 (2005); BBA 1757, 1035, (2006)]

The schematics of the pumping model