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Published on: April 16, 2018
Energy transduction in the methanogen Methanococcus voltae is based on a sodium current
Journal of Bacteriology
|September 1, 1992
Summary
Methanococcus voltae utilizes sodium ions, not protons, for ATP production. This archaeon generates energy via a sodium motive force, independent of proton gradients, supporting an Na+-translocating ATP synthase.
Area of Science:
- Microbiology
- Biochemistry
- Archaea Physiology
Background:
- Methanogenic archaea play crucial roles in anaerobic environments.
- Energy transduction mechanisms in archaea are diverse and not fully understood.
- The role of ion gradients in ATP synthesis varies across microbial domains.
Purpose of the Study:
- To investigate the ion coupling mechanism for ATP production in Methanococcus voltae.
- To determine whether sodium ions or protons are the primary coupling ions for energy generation.
- To elucidate the role of ion gradients and pumps in M. voltae's bioenergetics.
Main Methods:
- Measurement of membrane potential and transmembrane pH gradients under varying growth conditions.
- Assessment of ATP synthesis and cell growth in the presence of ionophores and inhibitors.
- Investigation of ion transport mechanisms, including Na+/H+ antiporter activity.
- Immunological comparison of M. voltae membrane components with known ATP synthases.
Main Results:
- M. voltae maintains a significant membrane potential but unfavorable pH gradients for proton motive force.
- Sodium ion gradients are maintained, and ATP synthesis is independent of proton motive force at alkaline pH.
- Evidence for a primary Na+ pump and a Na+/H+ antiporter, facilitating sodium ion translocation.
- ATP production is dependent on sodium ions, even with an imposed membrane potential.
Conclusions:
- ATP production in Methanococcus voltae is primarily driven by a sodium motive force, not a proton motive force.
- The organism employs an Na+-translocating ATP synthase, coupled to a primary Na+ pump.
- This finding highlights a distinct bioenergetic strategy within methanogenic archaea.
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