The Coupling of Light-Induced Electron Transfer and Proton Uptake: Refined Crystal Structures of Modified Reaction Centres from Rhodopseudomonas Viridis

1995 ◽  
pp. 571-574
Author(s):  
C. Roy D. Lancaster ◽  
Hartmut Michel
Keyword(s):  
Electron Transfer ◽  
Crystal Structures ◽  
Rhodopseudomonas Viridis ◽  
Reaction Centres ◽  
Proton Uptake

scholarly journals Mutation of a single residue in the ba3 oxidase specifically impairs protonation of the pump site

2015 ◽  
Vol 112 (11) ◽  
pp. 3397-3402 ◽  
Author(s):  
Christoph von Ballmoos ◽  
Nathalie Gonska ◽  
Peter Lachmann ◽  
Robert B. Gennis ◽  
Pia Ädelroth ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Time Constant ◽  
Thermus Thermophilus ◽  
Proton Translocation ◽  
Proton Pumping ◽  
Wild Type ◽  
Structural Variant ◽  
In The Wild ◽  
Membrane Bound ◽  
Proton Uptake

The ba3-type cytochrome c oxidase from Thermus thermophilus is a membrane-bound protein complex that couples electron transfer to O2 to proton translocation across the membrane. To elucidate the mechanism of the redox-driven proton pumping, we investigated the kinetics of electron and proton transfer in a structural variant of the ba3 oxidase where a putative “pump site” was modified by replacement of Asp372 by Ile. In this structural variant, proton pumping was uncoupled from internal electron transfer and O2 reduction. The results from our studies show that proton uptake to the pump site (time constant ∼65 μs in the wild-type cytochrome c oxidase) was impaired in the Asp372Ile variant. Furthermore, a reaction step that in the wild-type cytochrome c oxidase is linked to simultaneous proton uptake and release with a time constant of ∼1.2 ms was slowed to ∼8.4 ms, and in Asp372Ile was only associated with proton uptake to the catalytic site. These data identify reaction steps that are associated with protonation and deprotonation of the pump site, and point to the area around Asp372 as the location of this site in the ba3 cytochrome c oxidase.

Activation of a coordinated alkyne by electron transfer: crystal structures of [Ph2}{C(CO2Me)CH(CO2Me)}] and [PPh2}{C(CO2Me)C(CO2Me)}]

2000 ◽  
Vol 598 (2) ◽  
pp. 318-328 ◽  
Author(s):  
M.Fernanda N.N. Carvalho ◽  
Adelino M. Galvão ◽  
Armando J.L. Pombeiro ◽  
Jan Čermák ◽  
S. Šabata ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Crystal Structures
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