1. Structural basis of mitochondrial membrane bending by the I-II-III 2 -IV 2 supercomplex.
- Author
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Mühleip A, Flygaard RK, Baradaran R, Haapanen O, Gruhl T, Tobiasson V, Maréchal A, Sharma V, and Amunts A
- Subjects
- Electron Transport, Protein Multimerization, Protein Subunits chemistry, Protein Subunits metabolism, Molecular Dynamics Simulation, Binding Sites, Evolution, Molecular, Cryoelectron Microscopy, Electron Transport Complex III chemistry, Electron Transport Complex III metabolism, Electron Transport Complex III ultrastructure, Electron Transport Complex IV chemistry, Electron Transport Complex IV metabolism, Electron Transport Complex IV ultrastructure, Mitochondria chemistry, Mitochondria enzymology, Mitochondria metabolism, Mitochondria ultrastructure, Mitochondrial Membranes chemistry, Mitochondrial Membranes enzymology, Mitochondrial Membranes metabolism, Mitochondrial Membranes ultrastructure, Electron Transport Complex II chemistry, Electron Transport Complex II metabolism, Electron Transport Complex II ultrastructure, Electron Transport Complex I chemistry, Electron Transport Complex I metabolism, Electron Transport Complex I ultrastructure
- Abstract
Mitochondrial energy conversion requires an intricate architecture of the inner mitochondrial membrane
1 . Here we show that a supercomplex containing all four respiratory chain components contributes to membrane curvature induction in ciliates. We report cryo-electron microscopy and cryo-tomography structures of the supercomplex that comprises 150 different proteins and 311 bound lipids, forming a stable 5.8-MDa assembly. Owing to subunit acquisition and extension, complex I associates with a complex IV dimer, generating a wedge-shaped gap that serves as a binding site for complex II. Together with a tilted complex III dimer association, it results in a curved membrane region. Using molecular dynamics simulations, we demonstrate that the divergent supercomplex actively contributes to the membrane curvature induction and tubulation of cristae. Our findings highlight how the evolution of protein subunits of respiratory complexes has led to the I-II-III2 -IV2 supercomplex that contributes to the shaping of the bioenergetic membrane, thereby enabling its functional specialization., (© 2023. The Author(s).)- Published
- 2023
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