Restoration of electron transport without proton pumping in mammalian mitochondria.
We have restored the CoQ oxidative capacity of mouse mtDNA-less cells (rho degrees cells) by transforming them with the alternative oxidase Aox of Emericella nidulans. Cotransforming rho degrees cells with the NADH dehydrogenase of Saccharomyces cerevisiae, Ndi1 and Aox recovered the NADH DH/CoQ reductase and the CoQ oxidase activities. CoQ oxidation by AOX reduces the dependence of rho degrees cells on pyruvate and uridine. Coexpression of AOX and NDI1 further improves the recycling of NAD(+). Therefore, 2 single-protein enzymes restore the electron transport in mammalian mitochondria substituting >80 nuclear DNA-encoded and 11 mtDNA-encoded proteins. Because those enzymes do not pump protons, we were able to split electron transport and proton pumping (ATP synthesis) and inquire which of the metabolic deficiencies associated with the loss of oxidative phosphorylation should be attributed to each of the 2 processes.
Perales-Clemente
Ester
E
Departamento de Bioquímica. Universidad de Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain.
Bayona-Bafaluy
Maria Pilar
MP
Pérez-Martos
Acisclo
A
Barrientos
Antoni
A
Fernández-Silva
Patricio
P
Enriquez
Jose Antonio
JA
D000818:Animals; D002460:Cell Line; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D003999:Dichloroacetic Acid / Q000378:metabolism; D004579:Electron Transport / Q000502:physiology*; D042967:Electron Transport Complex I; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins; D009245:NADH Dehydrogenase / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010940:Plant Proteins; D017494:Proton Pumps / Q000378:metabolism*; D011522:Protons; D019289:Pyruvic Acid / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D014170:Transformation, Genetic; D014451:Ubiquinone / Q000235:genetics / Q000378:metabolism; D014529:Uridine / Q000378:metabolism; D000099188:Alternative Oxidase
D004272:DNA, Mitochondrial; D003999:Dichloroacetic Acid; D042967:Electron Transport Complex I; D005656:Fungal Proteins; D019344:Lactic Acid; D024101:Mitochondrial Proteins; D009245:NADH Dehydrogenase; D010088:Oxidoreductases; D010100:Oxygen; D010940:Plant Proteins; D017494:Proton Pumps; D011522:Protons; D019289:Pyruvic Acid; D029701:Saccharomyces cerevisiae Proteins; D014451:Ubiquinone; D014529:Uridine; D000099188:Alternative Oxidase; C493237:Ndi1 protein, S cerevisiae