6q9k
From Proteopedia
Crystal structure of reduced Aquifex aeolicus NADH-quinone oxidoreductase subunits NuoE and NuoF S96M bound to NADH
Structural highlights
Function[NUOE_AQUAE] NDH-1 shuttles electrons from NADH, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory chain. Couples the redox reaction to proton translocation (for every two electrons transferred, four hydrogen ions are translocated across the cytoplasmic membrane), and thus conserves the redox energy in a proton gradient (By similarity). [NUOF_AQUAE] NDH-1 shuttles electrons from NADH, via FMN and iron-sulfur (Fe-S) centers, to quinones in the respiratory chain. Couples the redox reaction to proton translocation (for every two electrons transferred, four hydrogen ions are translocated across the cytoplasmic membrane), and thus conserves the redox energy in a proton gradient (By similarity). Publication Abstract from PubMedRespiratory complex I plays a central role in cellular energy metabolism coupling NADH oxidation to proton translocation. In humans its dysfunction is associated with degenerative diseases. Here we report the structure of the electron input part of Aquifex aeolicus complex I at up to 1.8 A resolution with bound substrates in the reduced and oxidized states. The redox states differ by the flip of a peptide bond close to the NADH binding site. The orientation of this peptide bond is determined by the reduction state of the nearby [Fe-S] cluster N1a. Fixation of the peptide bond by site-directed mutagenesis led to an inactivation of electron transfer and a decreased reactive oxygen species (ROS) production. We suggest the redox-gated peptide flip to represent a previously unrecognized molecular switch synchronizing NADH oxidation in response to the redox state of the complex as part of an intramolecular feed-back mechanism to prevent ROS production. A mechanism to prevent production of reactive oxygen species by Escherichia coli respiratory complex I.,Schulte M, Frick K, Gnandt E, Jurkovic S, Burschel S, Labatzke R, Aierstock K, Fiegen D, Wohlwend D, Gerhardt S, Einsle O, Friedrich T Nat Commun. 2019 Jun 11;10(1):2551. doi: 10.1038/s41467-019-10429-0. PMID:31186428[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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