The proton pumping bo oxidase from Vitreoscilla.

ABSTRACT: The cytochrome bo₃ quinol oxidase from Vitreoscilla (vbo₃) catalyses oxidation of ubiquinol and reduction of O₂ to H₂O. Data from earlier studies suggested that the free energy released in this reaction is used to pump sodium ions instead of protons across a membrane. Here, we have studied the functional properties of heterologously expressed vbo₃ with a variety of methods. (i) Following oxygen consumption with a Clark-type electrode, we did not observe a measurable effect of Na⁺ on the oxidase activity of purified vbo₃ solubilized in detergent or reconstituted in liposomes. (ii) Using fluorescent dyes, we find that vbo₃ does not pump Na⁺ ions, but H⁺ across the membrane, and that

SUBMITTER: Graf S 

PROVIDER: S-EPMC6423279 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature