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Cryo-EM structures of complex I from mouse heart mitochondria in two biochemically defined states.

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Agip, Ahmed-Noor A 
Bridges, Hannah R 
Viscomi, Carlo 
Rawson, Shaun 


Complex I (NADH:ubiquinone oxidoreductase) uses the reducing potential of NADH to drive protons across the energy-transducing inner membrane and power oxidative phosphorylation in mammalian mitochondria. Recent cryo-EM analyses have produced near-complete models of all 45 subunits in the bovine, ovine and porcine complexes and have identified two states relevant to complex I in ischemia-reperfusion injury. Here, we describe the 3.3-Å structure of complex I from mouse heart mitochondria, a biomedically relevant model system, in the 'active' state. We reveal a nucleotide bound in subunit NDUFA10, a nucleoside kinase homolog, and define mechanistically critical elements in the mammalian enzyme. By comparisons with a 3.9-Å structure of the 'deactive' state and with known bacterial structures, we identify differences in helical geometry in the membrane domain that occur upon activation or that alter the positions of catalytically important charged residues. Our results demonstrate the capability of cryo-EM analyses to challenge and develop mechanistic models for mammalian complex I.



Animals, Binding Sites, Cryoelectron Microscopy, Electron Transport Complex I, Enzyme Activation, Mice, Mitochondria, Heart, Models, Molecular, NADH Dehydrogenase, Nucleotides, Phospholipids, Protein Structural Elements, Protein Structure, Quaternary, Protein Subunits, Ubiquinone

Journal Title

Nat Struct Mol Biol

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Springer Science and Business Media LLC
Medical Research Council (MC_U105663141)
MRC (MC_UP_1002/1)
Medical Research Council (MC_UP_1002/1)
MRC (MC_UP_1002/1)
Medical Research Council (MC_UU_00015/8)
MRC (MC_UU_00015/2)
MRC (MC_UU_00015/8)
Medical Research Council (MC_UU_00015/7)