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bioRxiv · 10.1101/2022.11.01.514700

Cryo-EM structures of mitochondrial respiratory complex I from Drosophila melanogaster

Agip, A.-N. A.·Chung, I.·Sanchez-Martinez, A.·Whitworth, A.·Hirst, J.
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Abstract

Respiratory complex I powers ATP synthesis by oxidative phosphorylation, exploiting the energy from NADH oxidation by ubiquinone to drive protons across an energy-transducing membrane. Drosophila melanogaster is a candidate model organism for complex I due to its high evolutionary conservation with the mammalian enzyme, well-developed genetic toolkit, and complex physiology for studies in specific cell types and tissues. Here, we isolate complex I from Drosophila and determine its structure, revealing a 43-subunit assembly with high structural homology to its 45-subunit mammalian counterpart, including a hitherto unknown homologue to subunit NDUFA3. The major conformational state of the Drosophila enzyme is the mammalian-type ready-to-go active resting state, with a fully ordered and enclosed ubiquinone-binding site, but a subtly altered global conformation related to changes in subunit ND6. The mammalian-type deactive pronounced resting state is not observed: in two minor states the ubiquinone-binding site is unchanged, but a deactive-type{pi} -bulge is present in ND6-TMH3. Our detailed structural knowledge of Drosophila complex I provides a foundation for new approaches to disentangle mechanisms of complex I catalysis and regulation in bioenergetics and physiology.

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Agip, A.-N. A., Chung, I., Sanchez-Martinez, A., Whitworth, A., Hirst, J.. 2022-11-01. Cryo-EM structures of mitochondrial respiratory complex I from Drosophila melanogaster. https://doi.org/10.1101/2022.11.01.514700

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