title: Structure of a mitochondrial supercomplex formed by respiratory-chain complexes I and III.
abstract: Mitochondria are central to the efficient provision of energy for eukaryotic cells. The oxidative-phosphorylation system of mitochondria consists of a series of five major membrane complexes: NADH-ubiquinone oxidoreductase (commonly known as complex I), succinate-ubiquinone oxidoreductase (complex II), ubiquinol-cytochrome c oxidoreductase (cytochrome bc1 complex or complex III), cytochrome c-O2 oxidoreductase (complex IV), and F1F0-ATP synthase (complex V). Several lines of evidence have recently suggested that complexes I and III-V might interact to form supercomplexes. However, because of their fragility, the structures of these supercomplexes are still unknown. A stable supercomplex consisting of complex I and dimeric complex III was purified from plant mitochondria. Structural characterization by single-particle EM indicates a specific type of interaction between monomeric complex I and dimeric complex III in a 1:1 ratio. We present a model for how complexes I and III are spatially organized within the I+III2 supercomplex.
authors.affiliation: Department of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Dudkina
authors.forename: Holger
authors.initials: H
authors.lastname: Eubel
authors.forename: Wilko
authors.initials: W
authors.lastname: Keegstra
authors.forename: Egbert J
authors.initials: EJ
authors.lastname: Boekema
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Braun
mesh_terms: D017360:Arabidopsis; D004579:Electron Transport; D042967:Electron Transport Complex I / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D014450:Electron Transport Complex III / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D008854:Microscopy, Electron; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D042967:Electron Transport Complex I; D014450:Electron Transport Complex III