7vyg
Membrane arm of active state CI from rotenone dataset
Structural highlights
FunctionNU3M_PIG 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 (By similarity). Publication Abstract from PubMedMammalian respiratory complex I (CI) is a 45-subunit, redox-driven proton pump that generates an electrochemical gradient across the mitochondrial inner membrane to power ATP synthesis in mitochondria. In the present study, we report cryo-electron microscopy structures of CI from Sus scrofa in six treatment conditions at a resolution of 2.4-3.5 A, in which CI structures of each condition can be classified into two biochemical classes (active or deactive), with a notably higher proportion of active CI particles. These structures illuminate how hydrophobic ubiquinone-10 (Q10) with its long isoprenoid tail is bound and reduced in a narrow Q chamber comprising four different Q10-binding sites. Structural comparisons of active CI structures from our decylubiquinone-NADH and rotenone-NADH datasets reveal that Q10 reduction at site 1 is not coupled to proton pumping in the membrane arm, which might instead be coupled to Q10 oxidation at site 2. Our data overturn the widely accepted previous proposal about the coupling mechanism of CI. The coupling mechanism of mammalian mitochondrial complex I.,Gu J, Liu T, Guo R, Zhang L, Yang M Nat Struct Mol Biol. 2022 Feb;29(2):172-182. doi: 10.1038/s41594-022-00722-w. , Epub 2022 Feb 10. PMID:35145322[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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