5W97

Crystal Structure of CO-bound Cytochrome c Oxidase determined by Serial Femtosecond X-Ray Crystallography at Room Temperature

Summary for 5W97

• Entry DOI: 10.2210/pdb5w97/pdb
• Descriptor: Cytochrome c oxidase subunit 1, Cytochrome c oxidase subunit 7A1, mitochondrial, Cytochrome c oxidase subunit 7B, mitochondrial, ... (28 entities in total)
• Functional Keywords: bioenergetics, proton translocation, oxidoreductase
• Biological source: Bos taurus (Bovine); More
• Total number of polymer chains: 26
• Total formula weight: 442812.02

Authors

Rousseau, D.L.,Yeh, S.-R.,Ishigami, I.,Zatsepin, N.A.,Grant, T.D.,Fromme, P.,Fromme, R. (deposition date: 2017-06-22, release date: 2017-08-09, Last modification date: 2023-10-04)

Primary citation

Ishigami, I.,Zatsepin, N.A.,Hikita, M.,Conrad, C.E.,Nelson, G.,Coe, J.D.,Basu, S.,Grant, T.D.,Seaberg, M.H.,Sierra, R.G.,Hunter, M.S.,Fromme, P.,Fromme, R.,Yeh, S.R.,Rousseau, D.L.
Crystal structure of CO-bound cytochrome c oxidase determined by serial femtosecond X-ray crystallography at room temperature.
Proc. Natl. Acad. Sci. U.S.A., 114:8011-8016, 2017

PubMed Abstract: Cytochrome oxidase (CO), the terminal enzyme in the electron transfer chain, translocates protons across the inner mitochondrial membrane by harnessing the free energy generated by the reduction of oxygen to water. Several redox-coupled proton translocation mechanisms have been proposed, but they lack confirmation, in part from the absence of reliable structural information due to radiation damage artifacts caused by the intense synchrotron radiation. Here we report the room temperature, neutral pH (6.8), damage-free structure of bovine CO (bCO) in the carbon monoxide (CO)-bound state at a resolution of 2.3 Å, obtained by serial femtosecond X-ray crystallography (SFX) with an X-ray free electron laser. As a comparison, an equivalent structure was obtained at a resolution of 1.95 Å, from data collected at a synchrotron light source. In the SFX structure, the CO is coordinated to the heme iron atom, with a bent Fe-C-O angle of ∼142°. In contrast, in the synchrotron structure, the Fe-CO bond is cleaved; CO relocates to a new site near Cu, which, in turn, moves closer to the heme iron by ∼0.38 Å. Structural comparison reveals that ligand binding to the heme iron in the SFX structure is associated with an allosteric structural transition, involving partial unwinding of the helix-X between heme and , thereby establishing a communication linkage between the two heme groups, setting the stage for proton translocation during the ensuing redox chemistry.

PubMed: 28698372
DOI: 10.1073/pnas.1705628114

Experimental method

X-RAY DIFFRACTION (2.3 Å)