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Proton migration along the membrane surface and retarded surface to bulk transfer
J Heberle1, J Riesle, G Thiedemann
1Hahn-Meitner-Institut, Berlin, Germany.
Nature
|August 4, 1994
Summary
Protons move rapidly along membrane surfaces, faster than through water. This localized proton diffusion allows efficient energy transfer to proteins like ATP synthase without energy loss.
Area of Science:
- Biochemistry
- Membrane Biology
- Bioenergetics
Background:
- The chemiosmotic theory explains how proton gradients drive cellular energy production.
- A debate exists on whether protons move through bulk water or along membrane surfaces to reach target proteins.
Purpose of the Study:
- To investigate the mechanism of proton transfer from membrane-bound proton pumps to proton-consuming proteins.
- To determine the relative rates of proton transfer along membrane surfaces versus through bulk water.
Main Methods:
- Studied proton release from an integral membrane protein.
- Measured the rate of proton transfer along the membrane surface.
- Calculated lateral proton diffusion rates considering membrane surface buffer capacity.
Main Results:
- Proton transfer along the membrane surface is faster than proton exchange with bulk water.
- Lateral proton diffusion rates can be quantified by surface buffer capacity.
- Efficient proton diffusion along the membrane surface occurs without significant dissipation.
Conclusions:
- Protons can efficiently travel along membrane surfaces to reach sinks like H(+)-ATP synthase.
- Localized proton transfer minimizes energy loss, supporting efficient bioenergetic processes.
- The findings favor a localized proton transfer model in membrane bioenergetics.