Charge displacements during ATP-hydrolysis and synthesis of the Na+-transporting FoF1-ATPase of Ilyobacter tartaricus.
Transient electrical currents generated by the Na(+)-transporting F(o)F(1)-ATPase of Ilyobacter tartaricus were observed in the hydrolytic and synthetic mode of the enzyme. Two techniques were applied: a photochemical ATP concentration jump on a planar lipid membrane and a rapid solution exchange on a solid supported membrane. We have identified an electrogenic reaction in the reaction cycle of the F(o)F(1)-ATPase that is related to the translocation of the cation through the membrane bound F(o) subcomplex of the ATPase. In addition, we have determined rate constants for the process: For ATP hydrolysis this reaction has a rate constant of 15-30 s(-1) if H(+) is transported and 30-60 s(-1) if Na(+) is transported. For ATP synthesis the rate constant is 50-70 s(-1).
Burzik
Christiane
C
Max-Planck-Institut für Biophysik, D-60596 Frankfurt/Main, Germany.
Kaim
Georg
G
Dimroth
Peter
P
Bamberg
Ernst
E
Fendler
Klaus
K
D000244:Adenosine Diphosphate / Q000737:chemistry; D000251:Adenosine Triphosphatases / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000096:biosynthesis / Q000737:chemistry* / Q000494:pharmacology; D001665:Binding Sites; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000737:chemistry; D002412:Cations; D002462:Cell Membrane / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D045182:Fusobacteria / Q000201:enzymology*; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D017136:Ion Transport / Q000502:physiology*; D007700:Kinetics; D008051:Lipid Bilayers; D008081:Liposomes / Q000378:metabolism; D008954:Models, Biological; D006180:Proton-Translocating ATPases / Q000096:biosynthesis* / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
D027682:Cation Transport Proteins; D002412:Cations; D008051:Lipid Bilayers; D008081:Liposomes; D000244:Adenosine Diphosphate; D006859:Hydrogen; D000255:Adenosine Triphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases; D006180:Proton-Translocating ATPases