Membrane plasticity facilitates recognition of the inhibitor oligomycin by the mitochondrial ATP synthase rotor

Abstract

Enzymes in the respiratory chain are increasingly seen as potential targets against multi-drug resistance of human pathogens and cancerous cells. However, a detailed understanding of the mechanism and specificity determinants of known inhibitors is still lacking. Oligomycin, for example, has been known to be an inhibitor of the membrane motor of the mitochondrial ATP synthase for over five decades, and yet little is known about its mode of action at the molecular level. In a recent breakthrough, a crystal structure of the S. cerevisiae c-subunit ring with bound oligomycin revealed the inhibitor docked on the outer face of the proton-binding sites, deep into the transmembrane region. However, the structure of the complex was obtained in an organic solvent rather than detergent or a lipid bilayer, and therefore it has been unclear whether this mode of recognition is physiologically relevant. Here, we use molecular dynamics simulations to address this question and gain insights into the mechanism of oligomycin inhibition. Our findings lead us to propose that oligomycin naturally partitions into the lipid/water interface, and that in this environment the inhibitor can indeed bind to any of the c-ring proton-carrying sites that are exposed to the membrane, thereby becoming an integral component of the proton-coordinating network. As the c-ring rotates within the membrane, driven either by downhill proton permeation or ATP hydrolysis, one of the protonated, oligomycin-bound sites eventually reaches the subunit-a interface and halts the rotary mechanism of the enzyme.

eIF2α mediated integrated stress response connects multiple intracellular signaling to reprogram vascular smooth muscle cell fate in carotid plaques

“…Consistent with the elevated mitochondrial ssion, Tom 20 and p-DRP1(S616) were up-regulated when cells were treated with HG and ox-LDL (Figure 3F, Supplementary Figure 2B). Both imaging and western blotting assay reveal that enhanced mitochondrial ssion caused by HG and ox-LDL were similar to the results induced by oligomycin A, an inhibitor of H + -ATP synthase promoting mitochondrial ssion and mitochondrial stress [34] (Figure 3D, 3E, 3F). The results indicated that HG and ox-LDL induced fragmented mitochondria are closely related to mitochondrial stress due to up-regulated mitochondrial ssion mediated by phosphorated DRP1 machinery during atherosclerosis.…”

Modified ZIF-8 Nanoparticles Attenuate Osteoarthritis by Reprogramming the Metabolic Pathway of Synovial Macrophages

“…FCCP, which can uncouple mitochondrial respiration, was used to measure the maximal and spare respiratory capacity. Rotenone and antimycin A blocked mitochondrial complexes I and III; therefore, the nonmitochondrial oxygen consumption could be calculated . For the ECAR assay, injection of glucose increased the value of ECAR, which represented the glycolysis rate.…”

“…Rotenone and antimycin A blocked mitochondrial complexes I and III; therefore, the nonmitochondrial oxygen consumption could be calculated. 56 For the ECAR assay, injection of glucose increased the value of ECAR, which represented the glycolysis rate. The increased value of ECAR after oligomycin injection indicated the glycolytic reserve and capacity.…”

Anti-Trypanosoma cruzi Activity of Metabolism Modifier Compounds

“…A secondary cell toxicity assay with monkey Vero cells was performed to test for parasite specificity of dorsomorphin and 17-DMAG compared to host cells. Oligomycin was discarded from further evaluation because it is highly toxic to human subjects [ 24 ].…”