Biochimica et Biophysica Acta-Bioenergetics最新文献

{"title":"Finding the E-channel proton loading sites by calculating the ensemble of protonation microstates","authors":"Md. Raihan Uddin ,&nbsp;Umesh Khaniya ,&nbsp;Chitrak Gupta ,&nbsp;Junjun Mao ,&nbsp;Gehan A. Ranepura ,&nbsp;Rongmei Judy Wei ,&nbsp;Jose Ortiz-Soto ,&nbsp;Abhishek Singharoy ,&nbsp;M.R. Gunner","doi":"10.1016/j.bbabio.2024.149518","DOIUrl":"10.1016/j.bbabio.2024.149518","url":null,"abstract":"<div><div>The aerobic electron transfer chain builds a proton gradient by proton coupled electron transfer reactions through a series of proteins. Complex I is the first enzyme in the sequence. Here transfer of two electrons from NADH to quinone yields four protons pumped from the membrane N- (negative, higher pH) side to the P- (positive, lower pH) side. Protons move through three linear antiporter paths, with a few amino acids and waters providing the route; and through the <em>E</em>-channel, a complex of competing paths, with clusters of interconnected protonatable residues.</div><div>Proton loading sites (PLS) transiently bind protons as they are transported from N- to P-compartments. PLS can be individual residues or extended clusters of residues. The program MCCE uses Monte Carlos sampling to analyze the <em>E</em>-channel proton binding in equilibrium with individual Molecular Dynamics snapshots from trajectories of <em>Thermus thermuphillus</em> Complex I in the apo, quinone and quinol bound states. At pH 7, the five <em>E</em>-channel subunits (Nqo4, Nqo7, Nqo8, Nqo10, and Nqo11) take &gt;25,000 protonation microstates, each with different residues protonated. The microstate explosion is tamed by analyzing interconnected clusters of residues along the proton transfer paths. A proton is bound and released from a cluster of five coupled residues on the protein N-side and to six coupled residues in the protein center. Loaded microstates bind protons to sites closer to the P-side in the forward pumping direction. MCCE microstate analysis identifies strongly coupled proton binding amongst individual residues in the two PLS clusters.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149518"},"PeriodicalIF":3.4,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142512372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How lipid transfer proteins and the mitochondrial membrane shape the kinetics of β-oxidation the liver","authors":"Christoff Odendaal,&nbsp;Dirk-Jan Reijngoud,&nbsp;Barbara M. Bakker","doi":"10.1016/j.bbabio.2024.149519","DOIUrl":"10.1016/j.bbabio.2024.149519","url":null,"abstract":"<div><div>The mitochondrial fatty acid β-oxidation (mFAO) is important for producing ATP under conditions of energetic stress, such as fasting and cold exposure. The regulation of this pathway is dependent on the kinetic properties of the enzymes involved. To better understand pathway behaviour, accurate enzyme kinetics is required. Setting up and interpreting such proper assays requires a good understanding of what influences the enzymes' kinetics. Often, knowing the buffer composition, pH, and temperature is considered to be sufficient.</div><div>Many mFAO enzymes are membrane-bound, however, and their kinetic properties depend on the composition and curvature of the mitochondrial membranes. These properties are, in turn, affected by metabolite concentrations, but are rarely accounted for in kinetic assays. Especially for carnitine palmitoyltransferase 1 (CPT1), this has been shown to be of great consequence.</div><div>Moreover, the enzymes of the mFAO metabolise water-insoluble acyl-CoA derivatives, which become toxic at high concentrations. <em>In vivo</em>, these are carried across the cytosol by intracellular lipid transfer proteins (iLTPs), such as the fatty-acid and acyl-CoA-binding proteins (FABP and ACBP, respectively). <em>In vitro</em>, this is often mimicked by using bovine serum albumin (BSA), which differs from the iLPTs in terms of its binding behaviour and subcellular localisation patterns.</div><div>In this review, we argue that the iLTPs and membrane properties cannot be ignored when measuring or interpreting the kinetics of mFAO enzymes. They should be considered fundamental to the activity of mFAO enzymes just as pH, buffer composition, and temperature are.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149519"},"PeriodicalIF":3.4,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142479904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lysine 204 is crucial for the antiport function of the human LAT1 transporter","authors":"Mariafrancesca Scalise ,&nbsp;Raffaella Scanga ,&nbsp;Lara Console ,&nbsp;Michele Galluccio ,&nbsp;Lorena Pochini ,&nbsp;Cesare Indiveri","doi":"10.1016/j.bbabio.2024.149520","DOIUrl":"10.1016/j.bbabio.2024.149520","url":null,"abstract":"<div><div>LAT1 (SLC7A5) catalyzes an antiport reaction of amino acids with specificity towards the essential ones. It is mainly expressed at the Blood Brain Barrier and placenta barriers, but it becomes over-expressed in virtually all human cancers even if originating from tissues with lower expression levels. The antiport reaction of LAT1 is crucial at the BBB since its inherited loss causes Autism Spectrum Disorder. We have investigated the possible molecular determinant of the antiport by site-directed mutagenesis, <em>in vitro</em> transport assay and computational analysis. Previous data indicated that mutation of K204 impairs, but does not knock-out LAT1 functionality. We have investigated the activity changes in the K204Q mutant by following the transport of [³H]-histidine, one of the major substrates, in proteoliposomes harbouring the WT or K204Q. In the mutant, the [³H]-histidine uptake and efflux are not more stimulated by the counter-substrate as they occur in the WT. Moreover, the mutation strongly decreases the substrate affinity and alters the pH dependence of K204Q. Molecular Dynamics analysis correlates well with the experimental data since it shows that substrate prematurely escapes the binding site. In addition, the K204Q shows a strongly increased mobility in those regions, transmembrane domains and random coils, involved in the transport cycle. The identified Lys residue could be responsible of the same phenomenon in those members of the SLC7 family, described as antiporters, in which it is conserved.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149520"},"PeriodicalIF":3.4,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142479905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The molecular structure of an axle-less F1-ATPase","authors":"Emily J. Furlong ,&nbsp;Ian-Blaine P. Reininger-Chatzigiannakis ,&nbsp;Yi C. Zeng ,&nbsp;Simon H.J. Brown ,&nbsp;Meghna Sobti ,&nbsp;Alastair G. Stewart","doi":"10.1016/j.bbabio.2024.149521","DOIUrl":"10.1016/j.bbabio.2024.149521","url":null,"abstract":"<div><div>F₁F_o ATP synthase is a molecular rotary motor that can generate ATP using a transmembrane proton motive force. Isolated F₁-ATPase catalytic cores can hydrolyse ATP, passing through a series of conformational states involving rotation of the central γ rotor subunit and the opening and closing of the catalytic β subunits. Cooperativity in F₁-ATPase has long thought to be conferred through the γ subunit, with three key interaction sites between the γ and β subunits being identified. Single molecule studies have demonstrated that the F₁ complexes lacking the γ axle still “rotate” and hydrolyse ATP, but with less efficiency. We solved the cryogenic electron microscopy structure of an axle-less <em>Bacillus</em> sp. PS3 F₁-ATPase. The unexpected binding-dwell conformation of the structure in combination with the observed lack of interactions between the axle-less γ and the open β subunit suggests that the complete γ subunit is important for coordinating efficient ATP binding of F₁-ATPase.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149521"},"PeriodicalIF":3.4,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142479906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metabolic impairments in neurodegeneration with brain iron accumulation","authors":"Agata Wydrych ,&nbsp;Barbara Pakuła ,&nbsp;Justyna Janikiewicz ,&nbsp;Aneta M. Dobosz ,&nbsp;Patrycja Jakubek-Olszewska ,&nbsp;Marta Skowrońska ,&nbsp;Iwona Kurkowska-Jastrzębska ,&nbsp;Maciej Cwyl ,&nbsp;Mariola Popielarz ,&nbsp;Paolo Pinton ,&nbsp;Barbara Zavan ,&nbsp;Agnieszka Dobrzyń ,&nbsp;Magdalena Lebiedzińska-Arciszewska ,&nbsp;Mariusz R. Więckowski","doi":"10.1016/j.bbabio.2024.149517","DOIUrl":"10.1016/j.bbabio.2024.149517","url":null,"abstract":"<div><div>Neurodegeneration with brain iron accumulation (NBIA) is a broad, heterogeneous group of rare inherited diseases (1–3 patients/1,000,000 people) characterized by progressive symptoms associated with excessive abnormal iron deposition in the brain. Approximately 15,000–20,000 individuals worldwide are estimated to be affected by NBIA. NBIA is usually associated with slowly progressive pyramidal and extrapyramidal symptoms, axonal motor neuropathy, optic nerve atrophy, cognitive impairment and neuropsychiatric disorders. To date, eleven subtypes of NBIA have been described and the most common ones include pantothenate kinase-associated neurodegeneration (PKAN), PLA2G6-associated neurodegeneration (PLAN), mitochondrial membrane protein-associated neurodegeneration (MPAN) and beta-propeller protein-associated neurodegeneration (BPAN). We present a comprehensive overview of the evidence for disturbed cellular homeostasis and metabolic alterations in NBIA variants, with a careful focus on mitochondrial bioenergetics and lipid metabolism which drives a new perspective in understanding the course of this infrequent malady.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149517"},"PeriodicalIF":3.4,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142376280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In isolated brown adipose tissue mitochondria, UCP1 is not essential for - nor involved in - the uncoupling effects of the classical uncouplers FCCP and DNP","authors":"Irina G. Shabalina,&nbsp;Beatriz Jiménez,&nbsp;Celso Pereira Batista Sousa-Filho,&nbsp;Barbara Cannon,&nbsp;Jan Nedergaard","doi":"10.1016/j.bbabio.2024.149516","DOIUrl":"10.1016/j.bbabio.2024.149516","url":null,"abstract":"<div><div>Recent patch-clamp studies of mitoplasts have challenged the traditional view that classical chemical uncoupling (by e.g. FCCP or DNP) is due to the protonophoric property of these substances themselves. These studies instead suggest that in brown-fat mitochondria, FCCP- and DNP-induced uncoupling is mediated through activation of UCP1 (and in other tissues by activation of the adenine nucleotide transporter). These studies thus advocate an entirely new paradigm for the interpretation of standard bioenergetic experiments.</div><div>To examine whether these patch-clamp results obtained in brown-fat mitoplasts are directly transferable to classical isolated brown-fat mitochondria studies, we investigated the effects of FCCP and DNP in brown-fat mitochondria from wildtype and UCP1 KO mice, comparing the FCCP and DNP effects with those of a fatty acid (oleate), a bona fide activator of UCP1.</div><div>Whereas the sensitivity of brown-fat mitochondria to oleate was much higher in UCP1-containing than in UCP1 KO mitochondria, there was no difference in sensitivity to FCCP and DNP between these mitochondria, neither in oxygen consumption rate nor in membrane potential studies. Correspondingly, the UCP1-dependent ability of GDP to competitively inhibit activation by oleate was not seen with FCCP and DNP.</div><div>It would thus be premature to abandon the established bioenergetic interpretation of chemical uncoupler effects in classical isolated brown-fat mitochondria—and probably also generally in this type of mitochondrial study. Understanding the molecular and structural reasons for the different outcomes of mitoplast and mitochondrial studies is a challenging task.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149516"},"PeriodicalIF":3.4,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142367319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An unusual triplet population pathway in the Reaction Centre of the Chlorophyll-d binding Photosystem I of A. marina, as revealed by a combination of TR-EPR and ODMR spectroscopies","authors":"Alessandro Agostini ,&nbsp;Andrea Calcinoni ,&nbsp;Anastasia A. Petrova ,&nbsp;Marco Bortolus ,&nbsp;Anna Paola Casazza ,&nbsp;Donatella Carbonera ,&nbsp;Stefano Santabarbara","doi":"10.1016/j.bbabio.2024.149515","DOIUrl":"10.1016/j.bbabio.2024.149515","url":null,"abstract":"<div><div>Photo-induced Chlorophyll (Chl) triplet states in the isolated Photosystem I (PSI) of <em>Acaryochloris marina</em>, that harbours Chl <em>d</em> as its main pigment, were investigated by Optically Detected Magnetic Resonance (ODMR) and Time-Resolved Electron Paramagnetic Resonance (TR-EPR), and as a function of pre-illumination of the sample under reducing redox poising. Fluorescence Detected Magnetic Resonance (FDMR) allowed resolving four Chl <em>d</em> triplet (³Chl <em>d</em>) populations (T₁-T₄) both in untreated and illuminated samples in the presence of ascorbate and <em>N</em>,<em>N</em>,<em>N</em>′,<em>N</em>′-tetramethyl-<em>p</em>-phenylenediamine (TMPD). The FDMR signals increased following the pre-illumination treatment, particularly for the T₃ and T₄ populations, which are therefore sensitive to the redox state of PSI cofactors. Microwave-induced Triplet minus Singlet (TmS) spectra were detected in the |D|-|E| resonance window of the T₃ and T₄ triplets. These showed a broad singlet bleaching centred at 740 nm and also displayed complex spectral structure with several derivative-like features, indicating that both the T₃ and T₄ ³Chl <em>d</em> populations are associated with the PSI reaction centre (RC) triplet, <span><math><msub><mmultiscripts><mi>P</mi><mprescripts></mprescripts><mrow></mrow><mn>3</mn></mmultiscripts><mn>740</mn></msub></math></span>. Parallel measurements by TR-EPR demonstrated that triplet signals observed under all conditions investigated are dominated by an electron spin polarisation (esp), which is typical of intersystem crossing, differently from what expected for recombination triplet states formed from a radical pair precursor. Moreover, stronger reductant conditions obtained by pre-illumination of the samples in the presence of dithionite and 5-methylphenazinium methyl sulfate (PMS) did not lead to a recombination triplet state esp, but rather to a decrease of the whole signal intensity. The energetics of <em>A. marina</em> PSI and the possible occurrence of distributions of cofactors redox properties are discussed in order to address the unexpected <span><math><msub><mmultiscripts><mi>P</mi><mprescripts></mprescripts><mrow></mrow><mn>3</mn></mmultiscripts><mn>740</mn></msub></math></span> esp.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149515"},"PeriodicalIF":3.4,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142331792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ROS production by cytochrome bc1: Its mechanism as inferred from the effects of heme b cofactor mutants","authors":"Jakub Pagacz ,&nbsp;Arkadiusz Borek ,&nbsp;Artur Osyczka","doi":"10.1016/j.bbabio.2024.149513","DOIUrl":"10.1016/j.bbabio.2024.149513","url":null,"abstract":"<div><div>Cytochrome <em>bc</em>₁ is one of the enzymes of electron transport chain responsible for generation of reactive oxygen species (ROS). While ROS are considered to be products of side reactions of quinol oxidation site (Q_o), molecular aspects of their generation remain unclear. One of them concerns significance of hemes <em>b</em> (<em>b</em>_L and <em>b</em>_H) redox potentials (<em>E</em>_m) and properties on ROS generation by Q_o. Here we addressed this question by examining ROS production in mutants of bacterial cytochrome <em>bc</em>₁ that replaced one of the His ligand of either heme <em>b</em>_L or <em>b</em>_H with Lys or Asn. We observed that severe slowing down of electron flow by the Asn mutants induces similar effects on ROS production as inhibition by antimycin in the native cytochrome <em>bc</em>₁ (WT). An increase in the <em>E</em>_m of hemes <em>b</em> (either <em>b</em>_L or <em>b</em>_H) in Lys mutants does not exert major effect on the ROS production level, compared to WT. The experimental data were analyzed in the frame of a dynamic model to conclude that the observed ROS rates and levels reflect a combinatory effect of two factors: probability of heme <em>b</em>_L being in the reduced state and probability of electron transfer from heme <em>b</em>_L towards Q_o. A significant contribution from short-circuits maintains the ROS levels at ~15 % in all tested forms. Overall, ROS production by cytochrome <em>bc</em>₁ shows remarkably low susceptibility to changes in the <em>E</em>_m of heme <em>b</em> cofactors, leaving significance of tuning the <em>E</em>_m of hemes <em>b</em> as factor limiting superoxide production an open question.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149513"},"PeriodicalIF":3.4,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142331805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GTP before ATP: The energy currency at the origin of genes","authors":"Natalia Mrnjavac,&nbsp;William F. Martin","doi":"10.1016/j.bbabio.2024.149514","DOIUrl":"10.1016/j.bbabio.2024.149514","url":null,"abstract":"<div><div>Life is an exergonic chemical reaction. Many individual reactions in metabolism entail slightly endergonic steps that are coupled to free energy release, typically as ATP hydrolysis, in order to go forward. ATP is almost always supplied by the rotor-stator ATP synthase, which harnesses chemiosmotic ion gradients. Because the ATP synthase is a protein, it arose after the ribosome did. What was the energy currency of metabolism before the origin of the ATP synthase and how (and why) did ATP come to be the universal energy currency? About 27 % of a cell's energy budget is consumed as GTP during translation. The universality of GTP-dependence in ribosome function indicates that GTP was the ancestral energy currency of protein synthesis. The use of GTP in translation and ATP in small molecule synthesis are conserved across all lineages, representing energetic compartments that arose in the last universal common ancestor, LUCA. And what came before GTP? Recent findings indicate that the energy supporting the origin of LUCA's metabolism stemmed from H₂-dependent CO₂ reduction along routes that strongly resemble the reactions and transition metal catalysts of the acetyl-CoA pathway.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149514"},"PeriodicalIF":3.4,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142331804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anaesthetics disrupt complex I-linked respiration and reverse the ATP synthase","authors":"Enrique Rodriguez ,&nbsp;Bella Peng ,&nbsp;Nick Lane","doi":"10.1016/j.bbabio.2024.149511","DOIUrl":"10.1016/j.bbabio.2024.149511","url":null,"abstract":"<div><div>The mechanism of volatile general anaesthetics has long been a mystery. Anaesthetics have no structural motifs in common, beyond lipid solubility, yet all exert a similar effect. The fact that the inert gas xenon is an anaesthetic suggests their common mechanism might relate to physical rather than chemical properties. Electron transfer through chiral proteins can induce spin polarization. Recent work suggests that anaesthetics dissipate spin polarization during electron transfer to oxygen, slowing respiration. Here we show that the volatile anaesthetics isoflurane and sevoflurane specifically disrupt complex I-linked respiration in the thoraces of <em>Drosophila melanogaster</em>, with less effect on maximal respiration. Suppression of complex I-linked respiration was greatest with isoflurane. Using high-resolution tissue fluorespirometry, we show that these anaesthetics simultaneously increase mitochondrial membrane potential, implying reversal of the ATP synthase. Inhibition of ATP synthase with oligomycin prevented respiration and increased membrane potential back to the maximal (LEAK state) potential. Magnesium-green fluorescence predicted a collapse in ATP availability following a single anaesthetic dose, consistent with ATP hydrolysis through reversal of the ATP synthase. Raised membrane potential corresponded to a rise in ROS flux, especially with isoflurane. Anaesthetic doses causing respiratory suppression were in the same range as those that induce anaesthesia, although we could not establish tissue concentrations. Our findings show that anaesthetics suppress complex I-linked respiration with concerted downstream effects. But we cannot explain why only mutations in complex I, and not elsewhere in the electron-transfer system, confer hypersensitivity to anaesthetics.</div></div>","PeriodicalId":50731,"journal":{"name":"Biochimica et Biophysica Acta-Bioenergetics","volume":"1866 1","pages":"Article 149511"},"PeriodicalIF":3.4,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142331802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}