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Updated: Aug 2, 2026
10:31
A Model Membrane Platform for Reconstituting Mitochondrial Membrane Dynamics
Published on: September 2, 2020
Reconstituted mitochondrial transhydrogenase is a transmembrane protein
FEBS Letters
|December 12, 1983
Summary
Bovine heart mitochondrial transhydrogenase spans the cell membrane. Substrate binding causes conformational changes in the enzyme domain facing the cell interior, affecting its function.
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Respiration
Background:
- Mitochondrial transhydrogenase is a redox-linked proton pump.
- Understanding its membrane topology is crucial for elucidating energy transduction mechanisms.
Purpose of the Study:
- To determine the membrane orientation of bovine heart mitochondrial transhydrogenase.
- To investigate the effect of substrate binding on enzyme conformation.
Main Methods:
- Functional and asymmetric insertion of transhydrogenase into liposomes.
- Photoaffinity labeling using N-(4-Azido-2-nitrophenyl)-2-aminoethylsulfonate (NAP-taurine).
- Enzyme activity assays and radioactive labeling.
Main Results:
- Transhydrogenase was inserted into liposomes with its active site facing outward.
- Photoaffinity labeling inhibited transhydrogenase activity in a light-dependent manner.
- Substrate binding (AcPyAD+) modulated labeling and enzyme activity, indicating conformational changes.
Conclusions:
- Bovine heart mitochondrial transhydrogenase spans the membrane.
- Substrate binding induces conformational alterations in the enzyme's domain exposed to the inner membrane surface.
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