Structural insights into functional properties of the oxidized form of cytochrome c oxidase
Cytochrome c oxidase (C c O) is an essential enzyme in mitochondrial and bacterial respiration. It catalyzes the four-electron reduction of molecular oxygen to water and harnesses the chemical energy to translocate four protons across biological membranes. The turnover of the C c O reaction involves...
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Published in | Nature communications Vol. 14; no. 1; p. 5752 |
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Main Authors | , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
16.09.2023
Nature Publishing Group Nature Portfolio |
Subjects | |
Online Access | Get full text |
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Summary: | Cytochrome
c
oxidase (C
c
O) is an essential enzyme in mitochondrial and bacterial respiration. It catalyzes the four-electron reduction of molecular oxygen to water and harnesses the chemical energy to translocate four protons across biological membranes. The turnover of the C
c
O reaction involves an oxidative phase, in which the reduced enzyme (R) is oxidized to the metastable O
H
state, and a reductive phase, in which O
H
is reduced back to the R state. During each phase, two protons are translocated across the membrane. However, if O
H
is allowed to relax to the resting oxidized state (O), a redox equivalent to O
H
, its subsequent reduction to R is incapable of driving proton translocation. Here, with resonance Raman spectroscopy and serial femtosecond X-ray crystallography (SFX), we show that the heme
a
3
iron and Cu
B
in the active site of the O state, like those in the O
H
state, are coordinated by a hydroxide ion and a water molecule, respectively. However, Y244, critical for the oxygen reduction chemistry, is in the neutral protonated form, which distinguishes O from O
H
, where Y244 is in the deprotonated tyrosinate form. These structural characteristics of O provide insights into the proton translocation mechanism of C
c
O.
Using resonance Raman spectroscopy and serial femtosecond X-ray crystallography, the authors show the heme a
3
iron and Cu
B
in the resting oxidized form of Cytochrome c Oxidase are coordinated by a hydroxide ion and a water molecule, respectively. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 USDOE |
ISSN: | 2041-1723 2041-1723 |
DOI: | 10.1038/s41467-023-41533-x |