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bioRxiv · 10.1101/2022.05.13.491814

Conformational changes in mitochondrial complex I from the thermophilic eukaryote Chaetomium thermophilum

Laube, E.·Meier-Credo, J.·Langer, J.·Kuehlbrandt, W.
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Abstract

Mitochondrial complex I is a redox-driven proton pump that generates proton-motive force across the inner mitochondrial membrane, powering oxidative phosphorylation and ATP synthesis in eukaryotes. We report the structure of complex I from the thermophilic fungus Chaetomium thermophilum, determined by cryoEM up to 2.4 [A] resolution. We show that the complex undergoes a transition between two conformations, which we refer to as form 1 and 2. The conformational switch is manifest in a twisting movement of the peripheral arm relative to the membrane arm, but most notably in substantial rearrangements of the Q-binding cavity and the E-channel, resulting in a continuous aqueous passage from the E-channel to subunit ND5 at the far end of the membrane arm. The conformational changes in the complex interior resemble those reported for mammalian complex I, suggesting a highly conserved, universal mechanism of coupling electron transport to proton pumping.

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Laube, E., Meier-Credo, J., Langer, J., Kuehlbrandt, W.. 2022-05-13. Conformational changes in mitochondrial complex I from the thermophilic eukaryote Chaetomium thermophilum. https://doi.org/10.1101/2022.05.13.491814

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