We have developed a simple native-like surface-tethered membrane system to investigate the activity of cbo(3) (cytochrome bo(3)), a terminal oxidase in Escherichia coli. The tethered membranes consist of E. coli inner-membrane extracts mixed with additional E. coli lipids containing various amounts of the cbo(3) substrate UQ-10 (ubiquinol-10). Tethered membranes are formed by self-assembly from...

BACKGROUND The Voltage Dependent Anion Channel (VDAC) is involved in control of autism. Treatments, including coenzyme Q, have had some success on autism control. DATA SOURCES Correlation of porin redox activity and expression of autism is based on extensive literature, especially studies of antibodies, identification of cytosolic nicotinamide adenine dinucleotide reduced (NADH) dehydrogenase...

The alternative oxidase (AOX) is a ubiquinol oxidase found in the mitochondrial respiratory chain of plants as well as some fungi and protists. It has been predicted to contain a coupled diiron center on the basis of a conserved sequence motif consisting of the proposed iron ligands, four glutamate and two histidine residues. However, this prediction has not been experimentally verified. Here w...

The cytochrome bd ubiquinol oxidase from Escherichia coli couples the exergonic two-electron oxidation of ubiquinol and four-electron reduction of O(2) to 2H(2)O to proton motive force generation by transmembrane charge separation. The oxidase contains two b-type hemes (b(558) and b(595)) and one heme d, where O(2) is captured and converted to water through sequential formation of a few interme...

The two-electron ubiquinol oxidation or ubiquinone reduction typically involves semiquinone (SQ) intermediates. Natural engineering of ubiquinone binding sites of bioenergetic enzymes secures that SQ is sufficiently stabilized, so that it does not leave the site to membranous environment before full oxidation/reduction is completed. The ubiquinol oxidation Qo site of cytochrome bc1 (mitochondri...

RegB is a membrane-spanning sensor kinase responsible for redox regulation of a wide variety of metabolic processes in numerous proteobacterial species. Here we show that full-length RegB purified from Escherichia coli membranes contains bound ubiquinone. Four conserved residues in the membrane-spanning domain of RegB are shown to have important roles in ubiquinone binding in vitro and redox se...