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Updated: Jul 28, 2026
10:39
Visualization of ATP Synthase Dimers in Mitochondria by Electron Cryo-tomography
Published on: September 14, 2014
Catalytic site forms and controls in ATP synthase catalysis.
1Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095-1570, USA. pdboyer@ucla.edu
Biochimica Et Biophysica Acta
|June 6, 2000
Summary
ATP synthase utilizes a minimal binding change mechanism involving 120-degree rotations for catalysis. Two substrate-bound sites suffice for high rates, with three-site occupancy occurring transiently.
Area of Science:
- Biochemistry
- Enzyme kinetics
- Molecular biology
Background:
- ATP synthase catalyzes ATP synthesis and hydrolysis, crucial for cellular energy.
- Understanding the catalytic mechanism, including substrate binding and conformational changes, is key.
- Previous models proposed various mechanisms for ATP synthase function.
Purpose of the Study:
- To present a minimal scheme for substrate binding and interconversion of catalytic sites in ATP synthase.
- To evaluate intermediate forms, steps, and experimental evidence related to ATP synthase catalysis.
- To assess the role of MgADP inhibition in understanding F1 ATPases.
Main Methods:
- Theoretical modeling of substrate binding and catalytic site interconversion.
- Review and evaluation of existing experimental data on ATP synthase function.
- Analysis of energy-dependent steps, proton translocation, and transition state involvement.
Main Results:
- A 120-degree rotation of gamma subunits relative to beta subunits drives catalytic site interconversion.
- Near-maximal catalytic rates are achieved with substrate binding at two sites; three-site occupancy is transient.
- Proposed key steps involve proton translocation-induced site deformation for ADP/Pi binding and ATP formation, and ATP binding preceding proton translocation in hydrolysis.
Conclusions:
- A binding change mechanism involving specific rotational steps explains ATP synthase catalysis.
- ADP binding is a critical regulator of rotation during ATP synthesis.
- Further research is needed to elucidate specific intermediate steps and the impact of MgADP inhibition.
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