title: Respiratory active mitochondrial supercomplexes.
abstract: The structural organization of the mitochondrial respiratory complexes as four big independently moving entities connected by the mobile carriers CoQ and cytochrome c has been challenged recently. Blue native gel electrophoresis reveals the presence of high-molecular-weight bands containing several respiratory complexes and suggesting an in vivo assembly status of these structures (respirasomes). However, no functional evidence of the activity of supercomplexes as true respirasomes has been provided yet. We have observed that (1) supercomplexes are not formed when one of their component complexes is absent; (2) there is a temporal gap between the formation of the individual complexes and that of the supercomplexes; (3) some putative respirasomes contain CoQ and cytochrome c; (4) isolated respirasomes can transfer electrons from NADH to O(2), that is, they respire. Therefore, we have demonstrated the existence of a functional respirasome and propose a structural organization model that accommodates these findings.
authors.affiliation: Departamento de Bioquimica, Universidad de Zaragoza, Miguel Servet, 177, 50013 Zaragoza, Spain.
authors.forename: Rebeca
authors.initials: R
authors.lastname: Acín-Pérez
authors.forename: Patricio
authors.initials: P
authors.lastname: Fernández-Silva
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Peleato
authors.forename: Acisclo
authors.initials: A
authors.lastname: Pérez-Martos
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Enriquez
mesh_terms: D000818:Animals; D019069:Cell Respiration; D045304:Cytochromes c / Q000378:metabolism; D004579:Electron Transport; D042967:Electron Transport Complex I / Q000378:metabolism; D014450:Electron Transport Complex III / Q000378:metabolism; D007739:L Cells; D008099:Liver / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D009243:NAD / Q000378:metabolism; D010085:Oxidative Phosphorylation; D014451:Ubiquinone / Q000378:metabolism
chemical_list: D009243:NAD; D014451:Ubiquinone; D045304:Cytochromes c; D025261:Mitochondrial Proton-Translocating ATPases; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III