Respiratory complex I drives proton translocation across energy-transducing membranes by NADH oxidation coupled with (ubi)quinone reduction. In humans, its dysfunction is associated with neurodegenerative diseases. The Escherichia coli complex represents the structural minimal form of an energy-converting NADH:ubiquinone oxidoreductase. Here, we report the structure of the peripheral arm of the E. coli complex I consisting of six subunits, the FMN cofactor, and nine iron-sulfur clusters at 2.7 Å resolution obtained by cryo electron microscopy. While the cofactors are in equivalent positions as in the complex from other species, individual subunits are adapted to the absence of supernumerary proteins to guarantee structural stability. The catalytically important subunits NuoC and D are fused resulting in a specific architecture of functional importance. Striking features of the E. coli complex are scrutinized by mutagenesis and biochemical characterization of the variants. Moreover, the arrangement of the subunits sheds light on the unknown assembly of the complex.
Organizational Affiliation:
Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany; Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CMC, Université de Strasbourg CNRS, 4 Rue Blaise Pascal, 67081 Strasbourg, France.
Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CMC, Université de Strasbourg CNRS, 4 Rue Blaise Pascal, 67081 Strasbourg, France.
Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CMC, Université de Strasbourg CNRS, 4 Rue Blaise Pascal, 67081 Strasbourg, France; University of Strasbourg, Institute for Advanced Studies (USIAS), 5 Allée du Général Rouvillois, 67083 Strasbourg, France.
Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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