title: Cardiolipin is associated with the terminal oxidase of an extremely halophilic archaeon.
abstract: Membranes having an a high content of cardiolipin were isolated from an extremely halophilic archaeon Halorubrum sp. Absorbance difference spectra of detergent-solubilized plasma membranes reduced by dithionite suggested the presence of b-type cytochromes. Non-denaturing gel electrophoresis revealed only one fraction having TMPD-oxidase activity in which cardiolipin was the major lipid component. The electroeluted fraction showed a cytochrome c oxidase activity characterized by the reduced minus oxidized difference spectra as a terminal heme-copper oxidase. The cytochrome c oxidase activity of the archaeal cardiolipin-rich membranes was inhibited by the cardiolipin-specific fluorescent marker 10-N-nonyl acridine orange (NAO) in a dose-dependent manner. The results indicate that an archaeal analogue of cardiolipin is tightly associated to archaeal terminal oxidases and is required for its optimal functioning.
authors.affiliation: Department of Medical Biochemistry, Medical Biology and Medical Physics, University of Bari, Bari, Italy. a.corcelli@biologia.uniba.it
authors.forename: Angela
authors.initials: A
authors.lastname: Corcelli
authors.forename: Simona
authors.initials: S
authors.lastname: Lobasso
authors.forename: Luigi L
authors.initials: LL
authors.lastname: Palese
authors.forename: Matilde Sublimi
authors.initials: MS
authors.lastname: Saponetti
authors.forename: Sergio
authors.initials: S
authors.lastname: Papa
mesh_terms: D000609:Aminoacridines / Q000737:chemistry; D002308:Cardiolipins / Q000302:isolation & purification / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology*; D003573:Cytochrome b Group / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D004227:Dithionite / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000378:metabolism; D004586:Electrophoresis; D016931:Halobacteriales / Q000201:enzymology*; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D010089:Oxidoreductases, N-Demethylating / Q000378:metabolism; D012995:Solubility; D013050:Spectrometry, Fluorescence
chemical_list: D000609:Aminoacridines; D002308:Cardiolipins; D003573:Cytochrome b Group; D003902:Detergents; D004227:Dithionite; D006418:Heme; C041691:10-N-nonylacridinium orange; D010088:Oxidoreductases; C024748:copper oxidase; D010089:Oxidoreductases, N-Demethylating; C022726:tetramethylphenylenediamine oxidase; D003576:Electron Transport Complex IV