The symbiotically essential cbb(3)-type oxidase of Bradyrhizobium japonicum is a proton pump.
Purified cbb(3)-type oxidase of Bradyrhizobium japonicum was reconstituted into phospholipid vesicles. Tight vesicles were obtained as shown by the disturbance of deltapH with CCCP and the membrane potential with valinomycin, which led to a six-fold increase in cytochrome c oxidase activity. The vesicles were thus suitable for proton translocation experiments. In the presence of valinomycin, a pulse with reduced cytochrome c caused an acidification with a subsequent alkalinization, whereas the same pulse caused only an alkalinization in the presence of valinomycin plus CCCP. We conclude that the cbb(3)-type oxidase of B. japonicum is a proton pump.
Arslan
E
E
Institut für Mikrobiologie, Eidgenössische Technische Hochschule, Schmelzbergstrasse 7, CH-8092, Zürich, Switzerland.
Kannt
A
A
Thöny-Meyer
L
L
Hennecke
H
H
D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001692:Biological Transport; D020369:Bradyrhizobium / Q000201:enzymology* / Q000235:genetics; D003574:Cytochrome c Group / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D017494:Proton Pumps / Q000235:genetics / Q000378:metabolism*; D011522:Protons; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D001426:Bacterial Proteins; D003574:Cytochrome c Group; C087009:FixN protein, bacteria; C080744:FixQ protein, Bacteria; D008565:Membrane Proteins; D017494:Proton Pumps; D011522:Protons; D011993:Recombinant Fusion Proteins; C080743:cytochrome FixO; C080742:cytochrome FixP; D010088:Oxidoreductases; C020094:duroquinol oxidase; D003576:Electron Transport Complex IV