1
|
Zhang M, Yu W, Zhou S, Zhang B, Lo ECM, Xu X, Zhang D. In vitro Antibacterial Activity of an FDA-Approved H +-ATPase Inhibitor, Bedaquiline, Against Streptococcus mutans in Acidic Milieus. Front Microbiol 2021; 12:647611. [PMID: 33717046 PMCID: PMC7947916 DOI: 10.3389/fmicb.2021.647611] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 01/29/2021] [Indexed: 12/28/2022] Open
Abstract
Background Dental caries is an acid-related disease. Current anti-caries agents mainly focus on the bacteriostatic effect in a neutral environment and do not target acid-resistant microorganisms related to caries in acidic milieus. Objectives To assess the in vitro antibacterial activities of bedaquiline against oral pathogens in acidic milieus. Methods Streptococcus mutans, Streptococcus sanguinis, and Streptococcus salivarius were used to prepare the mono-/multiple suspension and biofilm. The MIC and IC50 of bedaquiline against S. mutans were determined by the broth microdilution method. Bedaquiline was compared regarding (i) the inhibitory activity in pH 4–7 and at different time points against planktonic and biofilm; (ii) the effect on the production of lactic acid, extracellular polysaccharide, and pH of S. mutans biofilm; (iii) the cytotoxicity effects; and (iv) the activity on H+-ATPase enzyme of S. mutans. Results In pH 5 BHI, 2.5 mg/L (IC50) and 4 mg/L (MIC) of bedaquiline inhibited the proliferation and biofilm generation of S. mutans and Mix in a dose-dependent and time-dependent manner, but it was invalid in a neutral environment. The lactic acid production, polysaccharide production, and pH drop range reduced with the incorporation of bedaquiline in a pH 5 environment. Its inhibitory effect (>56 mg/L) against H+-ATPase enzyme in S. mutans and its non-toxic effect (<10 mg/L) on periodontal ligament stem cells were also confirmed. Conclusion Bedaquiline is efficient in inhibiting the proliferation and biofilm generation of S. mutans and other oral pathogens in an acidic environment. Its high targeting property and non-cytotoxicity also promote its clinical application potential in preventing caries. Further investigation of its specific action sites and drug modification are warranted.
Collapse
Affiliation(s)
- Meng Zhang
- Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University, Jinan, China.,Faculty of Dentistry, University of Hong Kong, Sai Ying Pun, Hong Kong
| | - Wenqian Yu
- Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Shujing Zhou
- Department of Stomatology, Maternal and Child Health Hospital of Liaocheng City, Liaocheng, China
| | - Bing Zhang
- Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University, Jinan, China
| | | | - Xin Xu
- Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Dongjiao Zhang
- Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University, Jinan, China
| |
Collapse
|
2
|
Emmanuel IA, Olotu FA, Agoni C, Soliman MES. In Silico Repurposing of J147 for Neonatal Encephalopathy Treatment: Exploring Molecular Mechanisms of Mutant Mitochondrial ATP Synthase. Curr Pharm Biotechnol 2020; 21:1551-1566. [PMID: 32598251 DOI: 10.2174/1389201021666200628152246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 03/25/2020] [Accepted: 05/08/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Neonatal Encephalopathy (NE) is a mitochondrial ATP synthase (mATPase) disease, which results in the death of infants. The case presented here is reportedly caused by complex V deficiency as a result of mutation of Arginine to Cysteine at residue 329 in the mATPase. A recent breakthrough was the discovery of J147, which targets mATPase in the treatment of Alzheimer's disease. Based on the concepts of computational target-based drug design, this study investigated the possibility of employing J147 as a viable candidate in the treatment of NE. OBJECTIVE/METHODS The structural dynamic implications of this drug on the mutated enzyme are yet to be elucidated. Hence, integrative molecular dynamics simulations and thermodynamic calculations were employed to investigate the activity of J147 on the mutated enzyme in comparison to its already established inhibitory activity on the wild-type enzyme. RESULTS A correlated structural trend occurred between the wild-type and mutant systems whereby all the systems exhibited an overall conformational transition. Equal observations in favorable free binding energies further substantiated uniformity in the mobility, and residual fluctuation of the wild-type and mutant systems. The similarity in the binding landscape suggests that J147 could as well modulate mutant mATPase activity in addition to causing structural modifications in the wild-type enzyme. CONCLUSION Findings suggest that J147 can stabilize the mutant protein and restore it to a similar structural state as the wild-type which depicts functionality. These details could be employed in drug design for potential drug resistance cases due to mATPase mutations that may present in the future.
Collapse
Affiliation(s)
- Iwuchukwu A Emmanuel
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa
| | - Fisayo A Olotu
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa
| | - Clement Agoni
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa
| | - Mahmoud E S Soliman
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa
| |
Collapse
|
3
|
|
4
|
Roy KK, Wani MA. Emerging opportunities of exploiting mycobacterial electron transport chain pathway for drug-resistant tuberculosis drug discovery. Expert Opin Drug Discov 2019; 15:231-241. [PMID: 31774006 DOI: 10.1080/17460441.2020.1696771] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Introduction: Tuberculosis (TB) is a leading infectious disease worldwide whose chemotherapy is challenged by the continued rise of drug resistance. This epidemic urges the need to discover anti-TB drugs with novel modes of action.Areas covered: The mycobacterial electron transport chain (ETC) pathway represents a hub of anti-TB drug targets. Herein, the authors highlight the various targets within the mycobacterial ETC and highlight some of the promising ETC-targeted drugs and clinical candidates that have been discovered or repurposed. Furthermore, recent breakthroughs in the availability of X-ray and/or cryo-EM structures of some targets are discussed, and various opportunities of exploiting these structures for the discovery of new anti-TB drugs are emphasized.Expert opinion: The drug discovery efforts targeting the ETC pathway have led to the FDA approval of bedaquiline, a FOF1-ATP synthase inhibitor, and the discovery of Q203, a clinical candidate drug targeting the mycobacterial cytochrome bcc-aa3 supercomplex. Moreover, clofazimine, a proposed prodrug competing with menaquinone for its reduction by mycobacterial NADH dehydrogenase 2, has been repurposed for TB treatment. Recently available structures of the mycobacterial ATP synthase C9 rotary ring and the cytochrome bcc-aa3 supercomplex represent further opportunities for the structure-based drug design (SBDD) of the next-generation of inhibitors against Mycobacterium tuberculosis.
Collapse
Affiliation(s)
- Kuldeep K Roy
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Kolkata, India
| | - Mushtaq Ahmad Wani
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Kolkata, India
| |
Collapse
|
5
|
Salifu EY, Agoni C, Olotu FA, Dokurugu YM, Soliman MES. Halting ionic shuttle to disrupt the synthetic machinery-Structural and molecular insights into the inhibitory roles of Bedaquiline towards Mycobacterium tuberculosis ATP synthase in the treatment of tuberculosis. J Cell Biochem 2019; 120:16108-16119. [PMID: 31125144 DOI: 10.1002/jcb.28891] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/26/2019] [Accepted: 03/15/2019] [Indexed: 12/31/2022]
Abstract
Therapeutic targeting of the adenosine triphosphate (ATP) machinery of Mycobacterium tuberculosis (Mtb) has recently presented a potent and alternative measure to halt the pathogenesis of tuberculosis. This has been potentiated by the development of bedaquiline (BDQ), a novel small molecule inhibitor that selectively inhibits mycobacterial F1 Fo -ATP synthase by targeting its rotor c-ring, resulting in the disruption of ATP synthesis and consequential cell death. Although the structural resolution of the mycobacterial C9 ring in co`mplex with BDQ provided the first-hand detail of BDQ interaction at the c-ring region of the ATP synthase, there still remains a need to obtain essential and dynamic insights into the mechanistic activity of this drug molecule towards crucial survival machinery of Mtb. As such, for the first time, we report an atomistic model to describe the structural dynamics that explicate the experimentally reported antagonistic features of BDQ in halting ion shuttling by the mycobacterial c-ring, using molecular dynamics simulation and the Molecular Mechanics/Poisson-Boltzmann Surface Area methods. Results showed that BDQ exhibited a considerably high ΔG while it specifically maintained high-affinity interactions with Glu65B and Asp32B , blocking their crucial roles in proton binding and shuttling, which is required for ATP synthesis. Moreover, the bulky nature of BDQ induced a rigid and compact conformation of the rotor c-ring, which impedes the essential rotatory motion that drives ion exchange and shuttling. In addition, the binding affinity of a BDQ molecule was considerably increased by the complementary binding of another BDQ molecule, which indicates that an increase in BDQ molecule enhances inhibitory potency against Mtb ATP synthase. Taken together, findings provide atomistic perspectives into the inhibitory mechanisms of BDQ coupled with insights that could enhance the structure-based design of novel ATP synthase inhibitors towards the treatment of tuberculosis.
Collapse
Affiliation(s)
- Elliasu Y Salifu
- Molecular Bio-computation and Drug Design Laboratory, Discipline of Pharmaceutical Chemistry, University of KwaZulu-Natal, Westville Campus, Durban, South Africa
| | - Clement Agoni
- Molecular Bio-computation and Drug Design Laboratory, Discipline of Pharmaceutical Chemistry, University of KwaZulu-Natal, Westville Campus, Durban, South Africa
| | - Fisayo A Olotu
- Molecular Bio-computation and Drug Design Laboratory, Discipline of Pharmaceutical Chemistry, University of KwaZulu-Natal, Westville Campus, Durban, South Africa
| | - Yussif M Dokurugu
- College of Pharmacy & Pharmaceutical Sciences, Institute of Public Health, Florida Agricultural & Mechanical University, Tallahassee, Florida
| | - Mahmoud E S Soliman
- Molecular Bio-computation and Drug Design Laboratory, Discipline of Pharmaceutical Chemistry, University of KwaZulu-Natal, Westville Campus, Durban, South Africa
| |
Collapse
|
6
|
Krasnoselska GO, Meier T. Purification and Reconstitution of Ilyobacter tartaricus ATP Synthase. Methods Mol Biol 2019; 1805:51-71. [PMID: 29971712 DOI: 10.1007/978-1-4939-8556-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
F-type adenosine triphosphate (ATP) synthase is a membrane-bound macromolecular complex, which is responsible for the synthesis of ATP, the universal energy source in living cells. This enzyme uses the proton- or sodium-motive force to power ATP synthesis by a unique rotary mechanism and can also operate in reverse, ATP hydrolysis, to generate ion gradients across membranes. The F1Fo-ATP synthases from bacteria consist of eight different structural subunits, forming a complex of ∼550 kDa in size. In the bacterium Ilyobacter tartaricus the ATP synthase has the stoichiometry α3β3γδεab2c11. This chapter describes a wet-lab working protocol for the purification of several tens of milligrams of pure, heterologously (E. coli-)produced I. tartaricus Na+-driven F1Fo-ATP synthase and its subsequent efficient reconstitution into proteoliposomes. The methods are useful for a broad range of subsequent biochemical and biotechnological applications.
Collapse
Affiliation(s)
- Ganna O Krasnoselska
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Thomas Meier
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
- Department of Life Sciences, Imperial College London, London, UK.
| |
Collapse
|
7
|
Rosàs-Canyelles E, Dai T, Li S, Herr AE. Mouse-to-mouse variation in maturation heterogeneity of smooth muscle cells. LAB ON A CHIP 2018; 18:1875-1883. [PMID: 29796562 PMCID: PMC6019577 DOI: 10.1039/c8lc00216a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Smooth muscle cell (SMC) heterogeneity plays an important role in vascular remodeling, a life-threatening hallmark of many vascular diseases. However, the characterization of SMCs at the single-cell level is stymied by drawbacks of contemporary single-cell protein measurements, including antibody probe cross-reactivity, chemical fixation artifacts, limited isoform-specific probes, low multiplexing and difficulty sampling cells with irregular morphologies. To scrutinize healthy vessels for subpopulations of SMCs with proliferative-like phenotypes, we developed a high-specificity, multiplexed single-cell immunoblotting cytometry tool for unfixed, uncultured primary cells. We applied our assay to demonstrate maturation stage profiling of aortic SMCs freshly isolated from individual mice. After ensuring unbiased sampling of SMCs (80-120 μm in length), we performed single-SMC electrophoretic protein separations, which resolve protein signal from off-target antibody binding, and immunoblotted for differentiation markers α-SMA, CNN-1 and SMMHC (targets ranging from 34 kDa to 227 kDa). We identified a subpopulation of immature-like SMCs, supporting the recently-established mechanism that only a subset of SMCs is responsible for vascular remodeling. Furthermore, the low sample requirements of our assay enable single-mouse resolution studies, which minimizes animal sacrifice and experimental costs while reporting animal-to-animal phenotypic variation, essential for achieving reproducibility and surmounting the drawbacks of pooling primary cells from different animals.
Collapse
|
8
|
Abstract
Mitochondria are the power stations of the eukaryotic cell, using the energy released by the oxidation of glucose and other sugars to produce ATP. Electrons are transferred from NADH, produced in the citric acid cycle in the mitochondrial matrix, to oxygen by a series of large protein complexes in the inner mitochondrial membrane, which create a transmembrane electrochemical gradient by pumping protons across the membrane. The flow of protons back into the matrix via a proton channel in the ATP synthase leads to conformational changes in the nucleotide binding pockets and the formation of ATP. The three proton pumping complexes of the electron transfer chain are NADH-ubiquinone oxidoreductase or complex I, ubiquinone-cytochrome c oxidoreductase or complex III, and cytochrome c oxidase or complex IV. Succinate dehydrogenase or complex II does not pump protons, but contributes reduced ubiquinone. The structures of complex II, III and IV were determined by x-ray crystallography several decades ago, but complex I and ATP synthase have only recently started to reveal their secrets by advances in x-ray crystallography and cryo-electron microscopy. The complexes I, III and IV occur to a certain extent as supercomplexes in the membrane, the so-called respirasomes. Several hypotheses exist about their function. Recent cryo-electron microscopy structures show the architecture of the respirasome with near-atomic detail. ATP synthase occurs as dimers in the inner mitochondrial membrane, which by their curvature are responsible for the folding of the membrane into cristae and thus for the huge increase in available surface that makes mitochondria the efficient energy plants of the eukaryotic cell.
Collapse
Affiliation(s)
- Joana S Sousa
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Edoardo D'Imprima
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
| |
Collapse
|
9
|
Kühlbrandt W, Davies KM. Rotary ATPases: A New Twist to an Ancient Machine. Trends Biochem Sci 2015; 41:106-116. [PMID: 26671611 DOI: 10.1016/j.tibs.2015.10.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 01/15/2023]
Abstract
Rotary ATPases are energy-converting nanomachines found in the membranes of all living organisms. The mechanism by which proton translocation through the membrane drives ATP synthesis, or how ATP hydrolysis generates a transmembrane proton gradient, has been unresolved for decades because the structure of a critical subunit in the membrane was unknown. Electron cryomicroscopy (cryoEM) studies of two rotary ATPases have now revealed a hairpin of long, horizontal, membrane-intrinsic α-helices in the a-subunit next to the c-ring rotor. The horizontal helices create a pair of aqueous half-channels in the membrane that provide access to the proton-binding sites in the rotor ring. These recent findings help to explain the highly conserved mechanism of ion translocation by rotary ATPases.
Collapse
Affiliation(s)
- Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany.
| | - Karen M Davies
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany
| |
Collapse
|
10
|
Preiss L, Langer JD, Yildiz Ö, Eckhardt-Strelau L, Guillemont JEG, Koul A, Meier T. Structure of the mycobacterial ATP synthase Fo rotor ring in complex with the anti-TB drug bedaquiline. SCIENCE ADVANCES 2015; 1:e1500106. [PMID: 26601184 PMCID: PMC4640650 DOI: 10.1126/sciadv.1500106] [Citation(s) in RCA: 203] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/04/2015] [Indexed: 05/12/2023]
Abstract
Multidrug-resistant tuberculosis (MDR-TB) is more prevalent today than at any other time in human history. Bedaquiline (BDQ), a novel Mycobacterium-specific adenosine triphosphate (ATP) synthase inhibitor, is the first drug in the last 40 years to be approved for the treatment of MDR-TB. This bactericidal compound targets the membrane-embedded rotor (c-ring) of the mycobacterial ATP synthase, a key metabolic enzyme required for ATP generation. We report the x-ray crystal structures of a mycobacterial c9 ring without and with BDQ bound at 1.55- and 1.7-Å resolution, respectively. The structures and supporting functional assays reveal how BDQ specifically interacts with the rotor ring via numerous interactions and thereby completely covers the c-ring's ion-binding sites. This prevents the rotor ring from acting as an ion shuttle and stalls ATP synthase operation. The structures explain how diarylquinoline chemicals specifically inhibit the mycobacterial ATP synthase and thus enable structure-based drug design of next-generation ATP synthase inhibitors against Mycobacterium tuberculosis and other bacterial pathogens.
Collapse
Affiliation(s)
- Laura Preiss
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Julian D. Langer
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Özkan Yildiz
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Luise Eckhardt-Strelau
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Jérôme E. G. Guillemont
- Johnson & Johnson Pharmaceutical Research and Development, Campus de Maigremont-BP615, 27106 Val de Reuil Cedex, France
| | - Anil Koul
- Department of Respiratory Infections, Infectious Diseases and Vaccines Group, Janssen Research and Development, Johnson & Johnson, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Thomas Meier
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
- Corresponding author: E-mail:
| |
Collapse
|
11
|
Abstract
Oxygenic photosynthesis is the principal converter of sunlight into chemical energy. Cyanobacteria and plants provide aerobic life with oxygen, food, fuel, fibers, and platform chemicals. Four multisubunit membrane proteins are involved: photosystem I (PSI), photosystem II (PSII), cytochrome b6f (cyt b6f), and ATP synthase (FOF1). ATP synthase is likewise a key enzyme of cell respiration. Over three billion years, the basic machinery of oxygenic photosynthesis and respiration has been perfected to minimize wasteful reactions. The proton-driven ATP synthase is embedded in a proton tight-coupling membrane. It is composed of two rotary motors/generators, FO and F1, which do not slip against each other. The proton-driven FO and the ATP-synthesizing F1 are coupled via elastic torque transmission. Elastic transmission decouples the two motors in kinetic detail but keeps them perfectly coupled in thermodynamic equilibrium and (time-averaged) under steady turnover. Elastic transmission enables operation with different gear ratios in different organisms.
Collapse
Affiliation(s)
- Wolfgang Junge
- Department of Biophysics, Universität Osnabrück, DE-49069 Osnabrück, Germany;
| | | |
Collapse
|
12
|
Martin J, Hudson J, Hornung T, Frasch WD. Fo-driven Rotation in the ATP Synthase Direction against the Force of F1 ATPase in the FoF1 ATP Synthase. J Biol Chem 2015; 290:10717-28. [PMID: 25713065 DOI: 10.1074/jbc.m115.646430] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Indexed: 11/06/2022] Open
Abstract
Living organisms rely on the FoF1 ATP synthase to maintain the non-equilibrium chemical gradient of ATP to ADP and phosphate that provides the primary energy source for cellular processes. How the Fo motor uses a transmembrane electrochemical ion gradient to create clockwise torque that overcomes F1 ATPase-driven counterclockwise torque at high ATP is a major unresolved question. Using single FoF1 molecules embedded in lipid bilayer nanodiscs, we now report the observation of Fo-dependent rotation of the c10 ring in the ATP synthase (clockwise) direction against the counterclockwise force of ATPase-driven rotation that occurs upon formation of a leash with Fo stator subunit a. Mutational studies indicate that the leash is important for ATP synthase activity and support a mechanism in which residues aGlu-196 and cArg-50 participate in the cytoplasmic proton half-channel to promote leash formation.
Collapse
Affiliation(s)
- James Martin
- From the School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501
| | - Jennifer Hudson
- From the School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501
| | - Tassilo Hornung
- From the School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501
| | - Wayne D Frasch
- From the School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501
| |
Collapse
|
13
|
Horizontal membrane-intrinsic α-helices in the stator a-subunit of an F-type ATP synthase. Nature 2015; 521:237-40. [PMID: 25707805 DOI: 10.1038/nature14185] [Citation(s) in RCA: 200] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/29/2014] [Indexed: 12/12/2022]
Abstract
ATP, the universal energy currency of cells, is produced by F-type ATP synthases, which are ancient, membrane-bound nanomachines. F-type ATP synthases use the energy of a transmembrane electrochemical gradient to generate ATP by rotary catalysis. Protons moving across the membrane drive a rotor ring composed of 8-15 c-subunits. A central stalk transmits the rotation of the c-ring to the catalytic F1 head, where a series of conformational changes results in ATP synthesis. A key unresolved question in this fundamental process is how protons pass through the membrane to drive ATP production. Mitochondrial ATP synthases form V-shaped homodimers in cristae membranes. Here we report the structure of a native and active mitochondrial ATP synthase dimer, determined by single-particle electron cryomicroscopy at 6.2 Å resolution. Our structure shows four long, horizontal membrane-intrinsic α-helices in the a-subunit, arranged in two hairpins at an angle of approximately 70° relative to the c-ring helices. It has been proposed that a strictly conserved membrane-embedded arginine in the a-subunit couples proton translocation to c-ring rotation. A fit of the conserved carboxy-terminal a-subunit sequence places the conserved arginine next to a proton-binding c-subunit glutamate. The map shows a slanting solvent-accessible channel that extends from the mitochondrial matrix to the conserved arginine. Another hydrophilic cavity on the lumenal membrane surface defines a direct route for the protons to an essential histidine-glutamate pair. Our results provide unique new insights into the structure and function of rotary ATP synthases and explain how ATP production is coupled to proton translocation.
Collapse
|
14
|
Interacting cytoplasmic loops of subunits a and c of Escherichia coli F1F0 ATP synthase gate H+ transport to the cytoplasm. Proc Natl Acad Sci U S A 2014; 111:16730-5. [PMID: 25385585 DOI: 10.1073/pnas.1414660111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
H(+)-transporting F1F0 ATP synthase catalyzes the synthesis of ATP via coupled rotary motors within F0 and F1. H(+) transport at the subunit a-c interface in transmembranous F0 drives rotation of a cylindrical c10 oligomer within the membrane, which is coupled to rotation of subunit γ within the α3β3 sector of F1 to mechanically drive ATP synthesis. F1F0 functions in a reversible manner, with ATP hydrolysis driving H(+) transport. ATP-driven H(+) transport in a select group of cysteine mutants in subunits a and c is inhibited after chelation of Ag(+) and/or Cd(+2) with the substituted sulfhydryl groups. The H(+) transport pathway mapped via these Ag(+)(Cd(+2))-sensitive Cys extends from the transmembrane helices (TMHs) of subunits a and c into cytoplasmic loops connecting the TMHs, suggesting these loop regions could be involved in gating H(+) release to the cytoplasm. Here, using select loop-region Cys from the single cytoplasmic loop of subunit c and multiple cytoplasmic loops of subunit a, we show that Cd(+2) directly inhibits passive H(+) transport mediated by F0 reconstituted in liposomes. Further, in extensions of previous studies, we show that the regions mediating passive H(+) transport can be cross-linked to each other. We conclude that the loop-regions in subunits a and c that are implicated in H(+) transport likely interact in a single structural domain, which then functions in gating H(+) release to the cytoplasm.
Collapse
|
15
|
Fillingame RH, Steed PR. Half channels mediating H+ transport and the mechanism of gating in the Fo sector of Escherichia coli F1Fo ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1063-8. [DOI: 10.1016/j.bbabio.2014.03.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/06/2014] [Accepted: 03/10/2014] [Indexed: 11/29/2022]
|
16
|
Cation transport by the respiratory NADH:quinone oxidoreductase (complex I): facts and hypotheses. Biochem Soc Trans 2014; 41:1280-7. [PMID: 24059520 DOI: 10.1042/bst20130024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The respiratory complex I (electrogenic NADH:quinone oxidoreductase) has been considered to act exclusively as a H+ pump. This was questioned when the search for the NADH-driven respiratory Na+ pump in Klebsiella pneumoniae initiated by Peter Dimroth led to the discovery of a Na+-translocating complex in this enterobacterium. The 3D structures of complex I from different organisms support the idea that the mechanism of cation transport by complex I involves conformational changes of the membrane-bound NuoL, NuoM and NuoN subunits. In vitro methods to follow Na+ transport were compared with in vivo approaches to test whether complex I, or its individual NuoL, NuoM or NuoN subunits, extrude Na+ from the cytoplasm to the periplasm of bacterial host cells. The truncated NuoL subunit of the Escherichia coli complex I which comprises amino acids 1-369 exhibits Na+ transport activity in vitro. This observation, together with an analysis of putative cation channels in NuoL, suggests that there exists in NuoL at least one continuous pathway for cations lined by amino acid residues from transmembrane segments 3, 4, 5, 7 and 8. Finally, we discuss recent studies on Na+ transport by mitochondrial complex I with respect to its putative role in the cycling of Na+ ions across the inner mitochondrial membrane.
Collapse
|
17
|
Stewart AG, Laming EM, Sobti M, Stock D. Rotary ATPases--dynamic molecular machines. Curr Opin Struct Biol 2013; 25:40-8. [PMID: 24878343 DOI: 10.1016/j.sbi.2013.11.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 11/20/2013] [Accepted: 11/26/2013] [Indexed: 01/14/2023]
Abstract
Recent work has provided the detailed overall architecture and subunit composition of three subtypes of rotary ATPases. Composite models of F-type, V-type and A-type ATPases have been constructed by fitting high-resolution X-ray structures of individual components into electron microscopy derived envelopes of the intact enzymes. Electron cryo-tomography has provided new insights into the supra-molecular arrangement of eukaryotic ATP synthases within mitochondria. An inherent flexibility in rotary ATPases observed by different techniques suggests greater dynamics during operation than previously envisioned. The concerted movement of subunits within the complex might provide means of regulation and information transfer between distant parts of rotary ATPases thereby fine tuning these molecular machines to their cellular environment, while optimizing their efficiency.
Collapse
Affiliation(s)
- Alastair G Stewart
- The Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia.
| | - Elise M Laming
- The Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia
| | - Meghna Sobti
- The Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia
| | - Daniela Stock
- The Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia
| |
Collapse
|
18
|
Zhang C, Allegretti M, Vonck J, Langer JD, Marcia M, Peng G, Michel H. Production of fully assembled and active Aquifex aeolicus F1FO ATP synthase in Escherichia coli. Biochim Biophys Acta Gen Subj 2013; 1840:34-40. [PMID: 24005236 DOI: 10.1016/j.bbagen.2013.08.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/13/2013] [Accepted: 08/27/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND F1FO ATP synthases catalyze the synthesis of ATP from ADP and inorganic phosphate driven by ion motive forces across the membrane. A number of ATP synthases have been characterized to date. The one from the hyperthermophilic bacterium Aquifex aeolicus presents unique features, i.e. a putative heterodimeric stalk. To complement previous work on the native form of this enzyme, we produced it heterologously in Escherichia coli. METHODS We designed an artificial operon combining the nine genes of A. aeolicus ATP synthase, which are split into four clusters in the A. aeolicus genome. We expressed the genes and purified the enzyme complex by affinity and size-exclusion chromatography. We characterized the complex by native gel electrophoresis, Western blot, and mass spectrometry. We studied its activity by enzymatic assays and we visualized its structure by single-particle electron microscopy. RESULTS We show that the heterologously produced complex has the same enzymatic activity and the same structure as the native ATP synthase complex extracted from A. aeolicus cells. We used our expression system to confirm that A. aeolicus ATP synthase possesses a heterodimeric peripheral stalk unique among non-photosynthetic bacterial F1FO ATP synthases. CONCLUSIONS Our system now allows performing previously impossible structural and functional studies on A. aeolicus F1FO ATP synthase. GENERAL SIGNIFICANCE More broadly, our work provides a valuable platform to characterize many other membrane protein complexes with complicated stoichiometry, i.e. other respiratory complexes, the nuclear pore complex, or transporter systems.
Collapse
Affiliation(s)
- Chunli Zhang
- Max Planck Institute of Biophysics, Department of Molecular Membrane Biology, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany
| | | | | | | | | | | | | |
Collapse
|
19
|
Moore KJ, Fillingame RH. Obstruction of transmembrane helical movements in subunit a blocks proton pumping by F1Fo ATP synthase. J Biol Chem 2013; 288:25535-25541. [PMID: 23864659 DOI: 10.1074/jbc.m113.496794] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Subunit a plays a key role in promoting H(+) transport-coupled rotary motion of the subunit c ring in F1Fo ATP synthase. H(+) binding and release occur at Asp-61 in the middle of the second transmembrane helix (TMH) of Fo subunit c. H(+) are thought to reach cAsp61 via aqueous half-channels formed by TMHs 2-5 of subunit a. Movements of TMH4 and TMH5 have been proposed to facilitate protonation of cAsp61 from a half channel centered in a four helix bundle at the periplasmic side of subunit a. The possible necessity of these proposed TMH movements was investigated by assaying ATP driven H(+) pumping function before and after cross-linking paired Cys substitutions at the center of TMHs within subunit a. The cross-linking of the Cys pairs aG218C/I248C in TMH4 and TMH5, and aL120C/H245C in TMH2 and TMH5, inhibited H(+) pumping by 85-90%. H(+) pumping function was largely unaffected by modification of the same Cys residues in the absence of cross-link formation. The inhibition is consistent with the proposed requirement for TMH movements during the gating of periplasmic H(+) access to cAsp61. The cytoplasmic loops of subunit a have been implicated in gating H(+) release to the cytoplasm, and previous cross-linking experiments suggest that the chemically reactive regions of the loops may pack as a single domain. Here we show that Cys substitutions in these domains can be cross-linked with retention of function and conclude that these domains need not undergo large conformational changes during enzyme function.
Collapse
Affiliation(s)
- Kyle J Moore
- From the Department of Biomolecular Chemistry, School of Medicine, and Public Health, University of Wisconsin, Madison, Wisconsin 53706
| | - Robert H Fillingame
- From the Department of Biomolecular Chemistry, School of Medicine, and Public Health, University of Wisconsin, Madison, Wisconsin 53706.
| |
Collapse
|
20
|
DeLeon-Rangel J, Ishmukhametov RR, Jiang W, Fillingame RH, Vik SB. Interactions between subunits a and b in the rotary ATP synthase as determined by cross-linking. FEBS Lett 2013; 587:892-7. [PMID: 23416299 DOI: 10.1016/j.febslet.2013.02.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 02/01/2013] [Accepted: 02/04/2013] [Indexed: 11/30/2022]
Abstract
The interaction of the membrane traversing stator subunits a and b of the rotary ATP synthase was probed by substitution of a single Cys into each subunit with subsequent Cu(2+) catalyzed cross-linking. Extensive interaction between the transmembrane (TM) region of one b subunit and TM2 of subunit a was indicated by cross-linking with 6 Cys pairs introduced into these regions. Additional disulfide cross-linking was observed between the N-terminus of subunit b and the periplasmic loop connecting TM4 and TM5 of subunit a. Finally, benzophenone-4-maleimide derivatized Cys in the 2-3 periplasmic loop of subunit a were shown to cross-link with the periplasmic N-terminal region of subunit b. These experiments help to define the juxtaposition of subunits b and a in the ATP synthase.
Collapse
Affiliation(s)
- Jessica DeLeon-Rangel
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275-0376, USA
| | | | | | | | | |
Collapse
|
21
|
Iino R, Noji H. Operation mechanism of F(o) F(1)-adenosine triphosphate synthase revealed by its structure and dynamics. IUBMB Life 2013; 65:238-46. [PMID: 23341301 DOI: 10.1002/iub.1120] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 11/26/2012] [Indexed: 11/11/2022]
Abstract
F(o) F(1) -Adenosine triphosphate (ATP) synthase, a complex of two rotary motor proteins, reversibly converts the electrochemical potential of protons across the cell membrane into phosphate transfer potential of ATP to provide the energy currency of the cell. The water-soluble motor is F(1) -ATPase, which possesses ATP synthesis/hydrolysis catalytic sites. Isolated F(1) hydrolyses ATP to rotate the rotary shaft against the stator ring. The membrane-embedded motor is F(o) , which is driven by proton flow down the proton electrochemical potential. In the F(o) F(1) complex, the direction of mechanical rotation, the chemical reaction, and the proton transport are determined by the relative amplitudes between the Gibbs free energy of the ATP hydrolysis reaction and the electrochemical potential of protons across the membrane. Therefore, F(o) F(1) -ATP synthase is a highly efficient molecular device in which the chemical, mechanical, and potential energies are tightly and reversibly converted. In this critical review, we summarize our latest knowledge about the operation mechanism of this sophisticated nanomachine, revealed by its structure and dynamics.
Collapse
Affiliation(s)
- Ryota Iino
- Department of Applied Chemistry, University of Tokyo, Bunkyo-ku, Tokyo, Japan.
| | | |
Collapse
|
22
|
Stewart AG, Sobti M, Harvey RP, Stock D. Rotary ATPases: models, machine elements and technical specifications. BIOARCHITECTURE 2013; 3:2-12. [PMID: 23369889 PMCID: PMC3639240 DOI: 10.4161/bioa.23301] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Rotary ATPases are molecular rotary motors involved in biological energy conversion. They either synthesize or hydrolyze the universal biological energy carrier adenosine triphosphate. Recent work has elucidated the general architecture and subunit compositions of all three sub-types of rotary ATPases. Composite models of the intact F-, V- and A-type ATPases have been constructed by fitting high-resolution X-ray structures of individual subunits or sub-complexes into low-resolution electron densities of the intact enzymes derived from electron cryo-microscopy. Electron cryo-tomography has provided new insights into the supra-molecular arrangement of eukaryotic ATP synthases within mitochondria and mass-spectrometry has started to identify specifically bound lipids presumed to be essential for function. Taken together these molecular snapshots show that nano-scale rotary engines have much in common with basic design principles of man made machines from the function of individual “machine elements” to the requirement of the right “fuel” and “oil” for different types of motors.
Collapse
Affiliation(s)
- Alastair G Stewart
- The Victor Chang Cardiac Research Institute, Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia
| | | | | | | |
Collapse
|
23
|
Sielaff H, Börsch M. Twisting and subunit rotation in single F(O)(F1)-ATP synthase. Philos Trans R Soc Lond B Biol Sci 2012; 368:20120024. [PMID: 23267178 DOI: 10.1098/rstb.2012.0024] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
F(O)F(1)-ATP synthases are ubiquitous proton- or ion-powered membrane enzymes providing ATP for all kinds of cellular processes. The mechanochemistry of catalysis is driven by two rotary nanomotors coupled within the enzyme. Their different step sizes have been observed by single-molecule microscopy including videomicroscopy of fluctuating nanobeads attached to single enzymes and single-molecule Förster resonance energy transfer. Here we review recent developments of approaches to monitor the step size of subunit rotation and the transient elastic energy storage mechanism in single F(O)F(1)-ATP synthases.
Collapse
Affiliation(s)
- Hendrik Sielaff
- Single-Molecule Microscopy Group, Jena University Hospital, Nonnenplan 2-4, 07743 Jena, Germany
| | | |
Collapse
|
24
|
Gohlke H, Schlieper D, Groth G. Resolving the negative potential side (n-side) water-accessible proton pathway of F-type ATP synthase by molecular dynamics simulations. J Biol Chem 2012; 287:36536-43. [PMID: 22942277 DOI: 10.1074/jbc.m112.398396] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The rotation of F(1)F(o)-ATP synthase is powered by the proton motive force across the energy-transducing membrane. The protein complex functions like a turbine; the proton flow drives the rotation of the c-ring of the transmembrane F(o) domain, which is coupled to the ATP-producing F(1) domain. The hairpin-structured c-protomers transport the protons by reversible protonation/deprotonation of a conserved Asp/Glu at the outer transmembrane helix (TMH). An open question is the proton transfer pathway through the membrane at atomic resolution. The protons are thought to be transferred via two half-channels to and from the conserved cAsp/Glu in the middle of the membrane. By molecular dynamics simulations of c-ring structures in a lipid bilayer, we mapped a water channel as one of the half-channels. We also analyzed the suppressor mutant cP24D/E61G in which the functional carboxylate is shifted to the inner TMH of the c-protomers. Current models concentrating on the "locked" and "open" conformations of the conserved carboxylate side chain are unable to explain the molecular function of this mutant. Our molecular dynamics simulations revealed an extended water channel with additional water molecules bridging the distance of the outer to the inner TMH. We suggest that the geometry of the water channel is an important feature for the molecular function of the membrane part of F(1)F(o)-ATP synthase. The inclination of the proton pathway isolates the two half-channels and may contribute to a favorable clockwise rotation in ATP synthesis mode.
Collapse
Affiliation(s)
- Holger Gohlke
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University, 40204 Düsseldorf, Germany
| | | | | |
Collapse
|