NADH:ubiquinone oxidoreductase (Complex I) ubiquinone-binding site (Complex I Q-site)

Mitochondrial Complex I (NADH:ubiquinone oxidoreductase) is the largest enzyme of the mitochondrial respiratory chain, playing a central role in cellular energy production (Source: UniProt). The Q-binding site is a narrow, hydrophobic tunnel where ubiquinone (Coenzyme Q10) is reduced to ubiquinol, a process coupled to the pumping of four protons across the inner mitochondrial membrane to drive ATP synthesis (Source: PubMed, PMID: 32555455). This site is a significant pharmacological target; for instance, the anti-diabetic drug metformin is known to inhibit Complex I at this site to activate the AMPK pathway and reduce hepatic glucose production (Source: NIH, StatPearls). However, dysfunction or potent inhibition of the Q-binding site by substances like rotenone is linked to increased reactive oxygen species (ROS) production and neurodegenerative conditions such as Parkinson's disease (Source: Wikipedia, "Complex I"). Mutations in the subunits forming this site are also associated with mitochondrial diseases like Leber's hereditary optic neuropathy (Source: MedlinePlus). Understanding the structural dynamics of this site is crucial for developing new therapeutics that can modulate mitochondrial function without inducing systemic toxicity.

Other names

NADH dehydrogenase (ubiquinone) Q-binding siteComplex I quinone-binding pocketUbiquinone-binding site of Complex IMitochondrial Complex I Q-binding site

Inhibition of electron transfer from the terminal iron-sulfur cluster (N2) to ubiquinone within the hydrophobic pocket, which reduces the proton motive force and can trigger secondary signaling pathways like AMPK activation (Source: PubMed, PMID: 25190156).