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F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes
Published on: May 4, 2013
ATP synthase complex from bovine heart mitochondria. Passive H+ conduction through mitochondrial coupling factor
1Department of Cell Physiology, Boston Biomedical Research Institute, Massachusetts 02114.
The Journal of Biological Chemistry
|September 15, 1989
Summary
Coupling factor 6 is not essential for proton flow through mitochondrial F0. Depleted particles show oligomycin-sensitive proton conductance, indicating an active proton channel independent of this factor.
Area of Science:
- Mitochondrial bioenergetics
- Protein complex function
- Membrane transport
Background:
- Mitochondrial ATP synthase is crucial for cellular energy production.
- Coupling factor 6 (CF6) has been implicated in regulating proton flow.
- Its precise role in mitochondrial F0 proton channel activity remains unclear.
Purpose of the Study:
- To investigate the necessity of coupling factor 6 for passive proton conductance through mitochondrial F0.
- To determine if CF6 is required for the inhibitor-sensitive proton channel activity of F0.
Main Methods:
- Submitochondrial particles were depleted of coupling factor 6 using ammonia and silicotungstic acid treatment.
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting confirmed CF6 deficiency.
- NADH-induced proton flux was measured via 9-amino-6-chloro-2-methoxyacridine fluorescence quenching.
Main Results:
- CF6-depleted particles exhibited reduced ATP-Pi exchange activity.
- Depleted particles showed negligible proton flux on their own.
- Oligomycin treatment significantly increased proton flux in depleted particles, indicating an active, inhibitable channel.
Conclusions:
- Coupling factor 6 is not essential for the existence of an inhibitor-sensitive proton channel in mitochondrial F0.
- Mitochondrial F0 possesses an active proton channel that can function independently of CF6.
- These findings redefine the role of CF6 in mitochondrial energy transduction.
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