Snapshot of an oxygen intermediate in the catalytic reaction of cytochrome c oxidase Academic Article uri icon

abstract

  • Cytochrome c oxidase (CcO) reduces dioxygen to water and harnesses the chemical energy to drive proton translocation across the inner mitochondrial membrane by an unresolved mechanism. By using time-resolved serial femtosecond crystallography, we identified a key oxygen intermediate of bovine CcO. It is assigned to the PR-intermediate, which is characterized by specific redox states of the metal centers and a distinct protein conformation. The heme a3 iron atom is in a ferryl (Fe4+ = O2−) configuration, and heme a and CuB are oxidized while CuA is reduced. A Helix-X segment is poised in an open conformational state; the heme a farnesyl sidechain is H-bonded to S382, and loop-I-II adopts a distinct structure. These data offer insights into the mechanism by which the oxygen chemistry is coupled to unidirectional proton translocation.

authors

  • Ishigami, Izumi
  • Lewis-Ballester, Ariel
  • Echelmeier, Austin
  • Brehm, Gerrit
  • Zatsepin, Nadia A
  • Grant, Thomas D
  • Coe, Jesse D
  • Lisova, Stella
  • Nelson, Garrett
  • Zhang, Shangji
  • Dobson, Zachary F
  • Boutet, Sébastien
  • Sierra, Raymond G
  • Batyuk, Alexander
  • Fromme, Petra
  • Fromme, Raimund
  • Spence, John CH
  • Ros, Alexandra
  • Yeh, Syun-Ru
  • Rousseau, Denis L

publication date

  • February 26, 2019