The symbiotically essential cbb 3‐type oxidase of Bradyrhizobium japonicum is a proton pump

FEBS Letters

Hennecke, Hauke²  Kannt, Aimo¹  Arslan, Engin²  Thöny-Meyer, Linda² 

[1] Abteilung Molekulare Membranbiologie, Max-Planck-Institut für Biophysik, Heinrich-Hoffmann-Strasse 7, D-60528 Frankfurt, Germany;Institut für Mikrobiologie, Eidgenössische Technische Hochschule, Schmelzbergstrasse 7, CH-8092 Zürich, Switzerland

关键词: Bradyrhizobium japonicum;    cbb 3-type oxidase;    Cytochrome c oxidase;    Nitrogen fixation;    Proton pumping;    CCCP;    carbonyl cyanide m-chlorophenylhydrazine;    Covs;    cytochrome c oxidase vesicles;    PMSF;    phenylmethylsulfonyl fluoride;    RCR;    respiratory control ratio;   

DOI  :  10.1016/S0014-5793(00)01277-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Purified cbb ₃-type oxidase of Bradyrhizobium japonicum was reconstituted into phospholipid vesicles. Tight vesicles were obtained as shown by the disturbance of ΔpH 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.

【 授权许可】

Unknown