Back to Search
Start Over
Promiscuous archaeal ATP synthase concurrently coupled to Na+ and H+ translocation.
- Source :
-
Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2012 Jan 17; Vol. 109 (3), pp. 947-52. Date of Electronic Publication: 2012 Jan 04. - Publication Year :
- 2012
-
Abstract
- ATP synthases are the primary source of ATP in all living cells. To catalyze ATP synthesis, these membrane-associated complexes use a rotary mechanism powered by the transmembrane diffusion of ions down a concentration gradient. ATP synthases are assumed to be driven either by H(+) or Na(+), reflecting distinct structural motifs in their membrane domains, and distinct metabolisms of the host organisms. Here, we study the methanogenic archaeon Methanosarcina acetivorans using assays of ATP hydrolysis and ion transport in inverted membrane vesicles, and experimentally demonstrate that the rotary mechanism of its ATP synthase is coupled to the concurrent translocation of both H(+) and Na(+) across the membrane under physiological conditions. Using free-energy molecular simulations, we explain this unprecedented observation in terms of the ion selectivity of the binding sites in the membrane rotor, which appears to have been tuned via amino acid substitutions so that ATP synthesis in M. acetivorans can be driven by the H(+) and Na(+) gradients resulting from methanogenesis. We propose that this promiscuity is a molecular mechanism of adaptation to life at the thermodynamic limit.
- Subjects :
- Adenosine Triphosphate metabolism
Biological Transport
Energy Metabolism
Hydrogen-Ion Concentration
Hydrolysis
Models, Biological
Protein Binding
Protein Subunits metabolism
Unilamellar Liposomes metabolism
Adenosine Triphosphatases metabolism
Methanosarcina enzymology
Protons
Sodium metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1091-6490
- Volume :
- 109
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 22219361
- Full Text :
- https://doi.org/10.1073/pnas.1115796109