A sodium ion-dependent A1AO ATP synthase from the hyperthermophilic archaeon Pyrococcus furiosus.
The rotor subunit c of the A(1)A(O) ATP synthase of the hyperthermophilic archaeon Pyrococcus furiosus contains a conserved Na(+)-binding motif, indicating that Na(+) is a coupling ion. To experimentally address the nature of the coupling ion, we isolated the enzyme by detergent solubilization from native membranes followed by chromatographic separation techniques. The entire membrane-embedded motor domain was present in the preparation. The rotor subunit c was found to form an SDS-resistant oligomer. Under the conditions tested, the enzyme had maximal activity at 100 degrees C, had a rather broad pH optimum between pH 5.5 and 8.0, and was inhibited by diethystilbestrol and derivatives thereof. ATP hydrolysis was strictly dependent on Na(+), with a K(m) of 0.6 mM. Li(+), but not K(+), could substitute for Na(+). The Na(+) dependence was less pronounced at higher proton concentrations, indicating competition between Na(+) and H(+) for a common binding site. Moreover, inhibition of the ATPase by N',N'-dicyclohexylcarbodiimide could be relieved by Na(+). Taken together, these data demonstrate the use of Na(+) as coupling ion for the A(1)A(O) ATP synthase of Pyrococcus furiosus, the first Na(+) A(1)A(O) ATP synthase described.
Pisa
Kim Y
KY
Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe Universität Frankfurt, Frankfurt, Germany.
Huber
Harald
H
Thomm
Michael
M
Müller
Volker
V
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D002234:Carbodiimides / Q000737:chemistry / Q000494:pharmacology; D002384:Catalysis; D002412:Cations / Q000737:chemistry; D002462:Cell Membrane / Q000201:enzymology; D017124:Conserved Sequence; D003510:Cyclohexanes / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis / Q000187:drug effects; D007700:Kinetics; D008969:Molecular Sequence Data; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020027:Pyrococcus furiosus / Q000201:enzymology* / Q000235:genetics; D016415:Sequence Alignment; D012964:Sodium / Q000494:pharmacology*; D012995:Solubility; D013696:Temperature
D002234:Carbodiimides; D002412:Cations; D003510:Cyclohexanes; D004791:Enzyme Inhibitors; D021122:Protein Subunits; C506365:Cyclohexane; D000255:Adenosine Triphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases