Formations of electrochemical proton gradient and adenosine triphosphate in proteoliposomes containing purified adenosine triphosphatase and bacteriorhodopsin.
Proteoliposome vesicles containing both bacteriorhodopsin of Halobacterium halobium and H+-translocating ATPase [EC 3.6,1.3] of a thermophilic bacterium, PS3, (TF0-F1) were reconstituted by either the dialysis method or the sonication method. Generation of the electrochemical proton gradient (deltamuH+) in these vesicles was measured using 9-aminoacridine for estimation of the chemical (deltapH) component and 8-anilinonaphthalene sulfonate for the electrical (deltaphi) component). In illuminated bacteriorhodopsin-vesicles the deltamuH+ reached 180-190 mV when reconstituted by the dialysis method and 210-220 mV when reconstituted by the sonication method. Vesicles reconstituted from both TF0-F1 and bacteriorhodopsin by the dialysis method generated a deltapH+ of about 200 mV on addition of ATP, while vesicles prepared by the sonication method generated very little deltamuH+, if any. These vesicles generated similar deltamuH+ on illumination to that found in bacteriorhodopsin-vesicles. Using vesicles reconstituted from both TF0-F1 and bacteriorhodopsin by the dialysis method, light dependent ATP synthesis was measured in relation to deltamuH+ formation. It was necessary to generate a deltamuH+ of above 170 mV for demonstration of appreciable formation of ATP and the greater the deltamuH+, the faster the rate of ATP synthesis.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate; D000817:Anilino Naphthalenesulfonates; D001436:Bacteriorhodopsins; D002338:Carotenoids; D004579:Electron Transport; D006217:Halobacterium / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008081:Liposomes; D009994:Osmolar Concentration; D011510:Proteolipids
D000817:Anilino Naphthalenesulfonates; D008081:Liposomes; D011510:Proteolipids; D002338:Carotenoids; D001436:Bacteriorhodopsins; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases