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ND3 Cys39 in complex I is exposed during mitochondrial respiration
Nils Burger1, Andrew M James1, John F Mulvey2
1Medical Research Council-Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.
Cell Chemical Biology
|November 5, 2021
Summary
Mammalian complex I
Area of Science:
- Biochemistry
- Mitochondrial respiration
- Enzyme kinetics
Background:
- Mammalian complex I (NADH:ubiquinone oxidoreductase) exists in active (A) and deactive (D) states.
- The ND3 subunit's Cys39 residue is hypothesized to be exposed in the D-state and occluded in the A-state, mediating the A/D transition.
Purpose of the Study:
- To quantify the A/D transition by measuring Cys39 exposure during complex I activity.
- To investigate the role of Cys39 in complex I function and regulation.
Main Methods:
- Isotopic labeling and mass spectrometry to measure Cys39 exposure.
- Assays of complex I NADH/CoQ oxidoreductase activity.
- Cys39 alkylation experiments in active and inactive complex I.
Main Results:
- Significant Cys39 exposure was observed during active NADH/CoQ oxidoreductase activity.
- Cys39 alkylation during respiration did not affect complex I activity.
- Alkylation of inactive complex I irreversibly inhibited NADH-dependent reactivation.
Conclusions:
- ND3 Cys39 is exposed during active mitochondrial respiration.
- This finding challenges the current model of the A/D transition.
- Cys39 plays a critical role in the regulation and reactivation of complex I.
Keywords:
Cys39NADH:ubiquinone oxidoreductaseactive/deactive transitioncomplex Iischemia-reperfusion (IR) injurymitochondriaredox regulationreverse electron transport (RET)More Related Videos
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