5o31
From Proteopedia
Mitochondrial complex I in the deactive state
Structural highlights
FunctionNU3M_BOVIN Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) that is believed to belong to the minimal assembly required for catalysis. Complex I functions in the transfer of electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone. Publication Abstract from PubMedComplex I (NADH:ubiquinone oxidoreductase) is central to energy metabolism in mammalian mitochondria. It couples NADH oxidation by ubiquinone to proton transport across the energy-conserving inner membrane, catalyzing respiration and driving ATP synthesis. In the absence of substrates, active complex I gradually enters a pronounced resting or deactive state. The active-deactive transition occurs during ischemia and is crucial for controlling how respiration recovers upon reperfusion. Here, we set a highly active preparation of Bos taurus complex I into the biochemically defined deactive state, and used single-particle electron cryomicroscopy to determine its structure to 4.1 A resolution. We show that the deactive state arises when critical structural elements that form the ubiquinone-binding site become disordered, and we propose reactivation is induced when substrate binding to the NADH-reduced enzyme templates their reordering. Our structure both rationalizes biochemical data on the deactive state and offers new insights into its physiological and cellular roles. Structure of the Deactive State of Mammalian Respiratory Complex I.,Blaza JN, Vinothkumar KR, Hirst J Structure. 2018 Feb 6;26(2):312-319.e3. doi: 10.1016/j.str.2017.12.014. Epub 2018, Jan 26. PMID:29395787[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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