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Kägi J, Sloan W, Schimpf J, Nasiri HR, Lashley D, Friedrich T. Exploring ND-011992, a quinazoline-type inhibitor targeting quinone reductases and quinol oxidases. Sci Rep 2023; 13:12226. [PMID: 37507428 PMCID: PMC10382516 DOI: 10.1038/s41598-023-39430-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023] Open
Abstract
Bacterial energy metabolism has become a promising target for next-generation tuberculosis chemotherapy. One strategy to hamper ATP production is to inhibit the respiratory oxidases. The respiratory chain of Mycobacterium tuberculosis comprises a cytochrome bcc:aa3 and a cytochrome bd ubiquinol oxidase that require a combined approach to block their activity. A quinazoline-type compound called ND-011992 has previously been reported to ineffectively inhibit bd oxidases, but to act bactericidal in combination with inhibitors of cytochrome bcc:aa3 oxidase. Due to the structural similarity of ND-011992 to quinazoline-type inhibitors of respiratory complex I, we suspected that this compound is also capable of blocking other respiratory chain complexes. Here, we synthesized ND-011992 and a bromine derivative to study their effect on the respiratory chain complexes of Escherichia coli. And indeed, ND-011992 was found to inhibit respiratory complex I and bo3 oxidase in addition to bd-I and bd-II oxidases. The IC50 values are all in the low micromolar range, with inhibition of complex I providing the lowest value with an IC50 of 0.12 µM. Thus, ND-011992 acts on both, quinone reductases and quinol oxidases and could be very well suited to regulate the activity of the entire respiratory chain.
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Affiliation(s)
- Jan Kägi
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Willough Sloan
- Department of Chemistry, William & Mary, Williamsburg, VA, USA
| | - Johannes Schimpf
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Hamid R Nasiri
- Department of Cellular Microbiology, University Hohenheim, Stuttgart, Germany
| | - Dana Lashley
- Department of Chemistry, William & Mary, Williamsburg, VA, USA.
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.
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2
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Kruth S, Nett M. Aurachins, Bacterial Antibiotics Interfering with Electron Transport Processes. Antibiotics (Basel) 2023; 12:1067. [PMID: 37370386 DOI: 10.3390/antibiotics12061067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/12/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Aurachins are farnesylated quinolone alkaloids of bacterial origin and excellent inhibitors of the respiratory chain in pro- and eukaryotes. Therefore, they have become important tool compounds for the investigation of electron transport processes and they also serve as lead structures for the development of antibacterial and antiprotozoal drugs. Especially aurachin D proved to be a valuable starting point for structure-activity relationship studies. Aurachin D is a selective inhibitor of the cytochrome bd oxidase, which has received increasing attention as a target for the treatment of infectious diseases caused by mycobacteria. Moreover, aurachin D possesses remarkable activities against Leishmania donovani, the causative agent of leishmaniasis. Aurachins are naturally produced by myxobacteria of the genus Stigmatella as well as by some Streptomyces and Rhodococcus strains. The recombinant production of these antibiotics turned out to be challenging due to their complex biosynthesis and their inherent toxicity. Recently, the biotechnological production of aurachin D was established in E. coli with a titer which is higher than previously reported from natural producer organisms.
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Affiliation(s)
- Sebastian Kruth
- Laboratory of Technical Biology, Department of Biochemical and Chemical Engineering, TU Dortmund University, 44227 Dortmund, Germany
| | - Markus Nett
- Laboratory of Technical Biology, Department of Biochemical and Chemical Engineering, TU Dortmund University, 44227 Dortmund, Germany
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3
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Grund TN, Kabashima Y, Kusumoto T, Wu D, Welsch S, Sakamoto J, Michel H, Safarian S. The cryoEM structure of cytochrome bd from C. glutamicum provides novel insights into structural properties of actinobacterial terminal oxidases. Front Chem 2023; 10:1085463. [PMID: 36688035 PMCID: PMC9846854 DOI: 10.3389/fchem.2022.1085463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/12/2022] [Indexed: 01/05/2023] Open
Abstract
Cytochromes bd are essential for microaerobic respiration of many prokaryotes including a number of human pathogens. These enzymes catalyze the reduction of molecular oxygen to water using quinols as electron donors. Their importance for prokaryotic survival and the absence of eukaryotic homologs make these enzyme ideal targets for antimicrobial drugs. Here, we determined the cryoEM structure of the menaquinol-oxidizing cytochrome bd-type oxygen reductase of the facultative anaerobic Actinobacterium Corynebacterium glutamicum at a resolution of 2.7 Å. The obtained structure adopts the signature pseudosymmetrical heterodimeric architecture of canonical cytochrome bd oxidases formed by the core subunits CydA and CydB. No accessory subunits were identified for this cytochrome bd homolog. The two b-type hemes and the oxygen binding heme d are organized in a triangular geometry with a protein environment around these redox cofactors similar to that of the closely related cytochrome bd from M. tuberculosis. We identified oxygen and a proton conducting channels emerging from the membrane space and the cytoplasm, respectively. Compared to the prototypical enzyme homolog from the E. coli, the most apparent difference is found in the location and size of the proton channel entry site. In canonical cytochrome bd oxidases quinol oxidation occurs at the highly flexible periplasmic Q-loop located in the loop region between TMHs six and seven. An alternative quinol-binding site near heme b 595 was previously identified for cytochrome bd from M. tuberculosis. We discuss the relevance of the two quinol oxidation sites in actinobacterial bd-type oxidases and highlight important differences that may explain functional and electrochemical differences between C. glutamicum and M. tuberculosis. This study expands our current understanding of the structural diversity of actinobacterial and proteobacterial cytochrome bd oxygen reductases and provides deeper insights into the unique structural and functional properties of various cytochrome bd variants from different phylae.
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Affiliation(s)
- Tamara N. Grund
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Yoshiki Kabashima
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Fukuoka, Japan
| | - Tomoichirou Kusumoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Fukuoka, Japan
| | - Di Wu
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Sonja Welsch
- Central Electron Microscopy Facility, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Junshi Sakamoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Fukuoka, Japan
| | - Hartmut Michel
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Schara Safarian
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt, Germany,Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand,Fraunhofer Institute for Translational Medicine and Pharmacology ITMP Frankfurt, Frankfurt, Germany,*Correspondence: Schara Safarian,
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4
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Zhao H, Ji R, Zha X, Xu Z, Lin Y, Zhou S. Investigation of the bactericidal mechanism of Penicilazaphilone C on Escherichia coli based on 4D label-free quantitative proteomic analysis. Eur J Pharm Sci 2022; 179:106299. [PMID: 36179970 DOI: 10.1016/j.ejps.2022.106299] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/16/2022] [Accepted: 08/27/2022] [Indexed: 11/03/2022]
Abstract
There is an urgent need to find new antibiotics to fight against the increasing drug resistance of microorganisms. A novel natural compound, Penicilazaphilone C (PAC), was isolated from a marine-derived fungus. It has displayed broad bactericidal activities against Gram-negative and Gram-positive bacteria. However, its bactericidal mechanism is still unknown. Herein, time-kill assays verified that PAC is a fast and efficient bactericidal agent. Furthermore, data from 4D label-free quantitative proteome assays revealed that PAC significantly influences over 898 proteins in Escherichia coli. Combining the results of biofilm formation, β-galactosidase measurement, TEM observation, soft agar plate swimming, reactive oxygen species measurement, qRT-PCR, and west-blotting, the mode of PAC action against E. coli was to block respiration, inhibit assimilatory nitrate reduction and dissimilar sulfur reduction, facilitate assimilatory sulfate reduction, suppress cysteine and methionine biosynthesis, down-regulate antioxidant protein expression and induced intracellular ROS accumulation, weaken bacterial chemotaxis, destroy flagellar assembly, etc., and finally cause the bacteria's death. Our findings suggest that PAC could have a multi-target regulatory effect on E. coli and could be used as a new antibiotic in medicine.
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Affiliation(s)
- Huange Zhao
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Control of Tropical Disease Control, Hainan Provincial Key Laboratory of Tropical Medicine, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199
| | - Rong Ji
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Control of Tropical Disease Control, Hainan Provincial Key Laboratory of Tropical Medicine, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199
| | - Xiangru Zha
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Control of Tropical Disease Control, Hainan Provincial Key Laboratory of Tropical Medicine, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199
| | - Zhen Xu
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Control of Tropical Disease Control, Hainan Provincial Key Laboratory of Tropical Medicine, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199
| | - Yingying Lin
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Control of Tropical Disease Control, Hainan Provincial Key Laboratory of Tropical Medicine, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199
| | - Songlin Zhou
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Control of Tropical Disease Control, Hainan Provincial Key Laboratory of Tropical Medicine, School of Tropical Medicine, Hainan Medical University, Haikou, Hainan, 571199.
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5
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Response of Mycobacterium smegmatis to the Cytochrome bcc Inhibitor Q203. Int J Mol Sci 2022; 23:ijms231810331. [PMID: 36142240 PMCID: PMC9498996 DOI: 10.3390/ijms231810331] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
For the design of next-generation tuberculosis chemotherapy, insight into bacterial defence against drugs is required. Currently, targeting respiration has attracted strong attention for combatting drug-resistant mycobacteria. Q203 (telacebec), an inhibitor of the cytochrome bcc complex in the mycobacterial respiratory chain, is currently evaluated in phase-2 clinical trials. Q203 has bacteriostatic activity against M. tuberculosis, which can be converted to bactericidal activity by concurrently inhibiting an alternative branch of the mycobacterial respiratory chain, cytochrome bd. In contrast, non-tuberculous mycobacteria, such as Mycobacterium smegmatis, show only very little sensitivity to Q203. In this report, we investigated factors that M. smegmatis employs to adapt to Q203 in the presence or absence of a functional cytochrome bd, especially regarding its terminal oxidases. In the presence of a functional cytochrome bd, M. smegmatis responds to Q203 by increasing the expression of cytochrome bcc as well as of cytochrome bd, whereas a M. smegmatisbd-KO strain adapted to Q203 by increasing the expression of cytochrome bcc. Interestingly, single-cell studies revealed cell-to-cell variability in drug adaptation. We also investigated the role of a putative second cytochrome bd isoform postulated for M. smegmatis. Although this putative isoform showed differential expression in response to Q203 in the M. smegmatisbd-KO strain, it did not display functional features similar to the characterised cytochrome bd variant.
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6
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Kägi J, Makarchuk I, Wohlwend D, Melin F, Friedrich T, Hellwig P. E. coli cytochrome bd-I requires Asp58 in the CydB subunit for catalytic activity. FEBS Lett 2022; 596:2418-2424. [PMID: 36029102 DOI: 10.1002/1873-3468.14482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/17/2022] [Accepted: 08/17/2022] [Indexed: 11/07/2022]
Abstract
The reduction of oxygen to water is crucial to life and a central metabolic process. To fulfill this task, prokaryotes use among other enzymes cytochrome bd oxidases (Cyt bds) that also play an important role in bacterial virulence and antibiotic resistance. To fight microbial infections by pathogens, an in-depth understanding of the enzyme mechanism is required. Here, we combine bioinformatics, mutagenesis, enzyme kinetics and FTIR spectroscopy to demonstrate that proton delivery to the active site contributes to the rate limiting steps in Cyt bd-I and involves Asp58 of subunit CydB. Our findings reveal a previously unknown catalytic function of subunit CydB in the reaction of Cyt bd-I.
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Affiliation(s)
- Jan Kägi
- Institut für Biochemie, Albert-Ludwigs-Universität, Albertstr 21, 79104, Freiburg, Germany
| | - Iryna Makarchuk
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg-CNRS 4, Rue Blaise Pascal, 67081, Strasbourg, France
| | - Daniel Wohlwend
- Institut für Biochemie, Albert-Ludwigs-Universität, Albertstr 21, 79104, Freiburg, Germany
| | - Frédéric Melin
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg-CNRS 4, Rue Blaise Pascal, 67081, Strasbourg, France
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität, Albertstr 21, 79104, Freiburg, Germany
| | - Petra Hellwig
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg-CNRS 4, Rue Blaise Pascal, 67081, Strasbourg, France
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7
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Friedrich T, Wohlwend D, Borisov VB. Recent Advances in Structural Studies of Cytochrome bd and Its Potential Application as a Drug Target. Int J Mol Sci 2022; 23:ijms23063166. [PMID: 35328590 PMCID: PMC8951039 DOI: 10.3390/ijms23063166] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/14/2022] [Accepted: 03/14/2022] [Indexed: 02/06/2023] Open
Abstract
Cytochrome bd is a triheme copper-free terminal oxidase in membrane respiratory chains of prokaryotes. This unique molecular machine couples electron transfer from quinol to O2 with the generation of a proton motive force without proton pumping. Apart from energy conservation, the bd enzyme plays an additional key role in the microbial cell, being involved in the response to different environmental stressors. Cytochrome bd promotes virulence in a number of pathogenic species that makes it a suitable molecular drug target candidate. This review focuses on recent advances in understanding the structure of cytochrome bd and the development of its selective inhibitors.
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Affiliation(s)
- Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany; (T.F.); (D.W.)
| | - Daniel Wohlwend
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany; (T.F.); (D.W.)
| | - Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow, Russia
- Correspondence:
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8
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Yadavalli SS, Yuan J. Bacterial Small Membrane Proteins: the Swiss Army Knife of Regulators at the Lipid Bilayer. J Bacteriol 2022; 204:e0034421. [PMID: 34516282 PMCID: PMC8765417 DOI: 10.1128/jb.00344-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Small membrane proteins represent a subset of recently discovered small proteins (≤100 amino acids), which are a ubiquitous class of emerging regulators underlying bacterial adaptation to environmental stressors. Until relatively recently, small open reading frames encoding these proteins were not designated genes in genome annotations. Therefore, our understanding of small protein biology was primarily limited to a few candidates associated with previously characterized larger partner proteins. Following the first systematic analyses of small proteins in Escherichia coli over a decade ago, numerous small proteins across different bacteria have been uncovered. An estimated one-third of these newly discovered proteins in E. coli are localized to the cell membrane, where they may interact with distinct groups of membrane proteins, such as signal receptors, transporters, and enzymes, and affect their activities. Recently, there has been considerable progress in functionally characterizing small membrane protein regulators aided by innovative tools adapted specifically to study small proteins. Our review covers prototypical proteins that modulate a broad range of cellular processes, such as transport, signal transduction, stress response, respiration, cell division, sporulation, and membrane stability. Thus, small membrane proteins represent a versatile group of physiology regulators at the membrane and the whole cell. Additionally, small membrane proteins have the potential for clinical applications, where some of the proteins may act as antibacterial agents themselves while others serve as alternative drug targets for the development of novel antimicrobials.
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Affiliation(s)
- Srujana S. Yadavalli
- Waksman Institute of Microbiology, Rutgers University, Piscataway, New Jersey, USA
- Department of Genetics, Rutgers University, Piscataway, New Jersey, USA
| | - Jing Yuan
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
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9
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Structure of Escherichia coli cytochrome bd-II type oxidase with bound aurachin D. Nat Commun 2021; 12:6498. [PMID: 34764272 PMCID: PMC8585947 DOI: 10.1038/s41467-021-26835-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Cytochrome bd quinol:O2 oxidoreductases are respiratory terminal oxidases so far only identified in prokaryotes, including several pathogenic bacteria. Escherichia coli contains two bd oxidases of which only the bd-I type is structurally characterized. Here, we report the structure of the Escherichia coli cytochrome bd-II type oxidase with the bound inhibitor aurachin D as obtained by electron cryo-microscopy at 3 Å resolution. The oxidase consists of subunits AppB, C and X that show an architecture similar to that of bd-I. The three heme cofactors are found in AppC, while AppB is stabilized by a structural ubiquinone-8 at the homologous positions. A fourth subunit present in bd-I is lacking in bd-II. Accordingly, heme b595 is exposed to the membrane but heme d embedded within the protein and showing an unexpectedly high redox potential is the catalytically active centre. The structure of the Q-loop is fully resolved, revealing the specific aurachin binding. Terminal bd oxidases endow bacterial pathogens with resistance to cellular stressors. The authors report the structure of E. coli bd-II type oxidase with the bound inhibitor aurachin D, providing a structural basis for the design of specifically binding antibiotics.
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10
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Safarian S, Opel-Reading HK, Wu D, Mehdipour AR, Hards K, Harold LK, Radloff M, Stewart I, Welsch S, Hummer G, Cook GM, Krause KL, Michel H. The cryo-EM structure of the bd oxidase from M. tuberculosis reveals a unique structural framework and enables rational drug design to combat TB. Nat Commun 2021; 12:5236. [PMID: 34475399 PMCID: PMC8413341 DOI: 10.1038/s41467-021-25537-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/17/2021] [Indexed: 02/07/2023] Open
Abstract
New drugs are urgently needed to combat the global TB epidemic. Targeting simultaneously multiple respiratory enzyme complexes of Mycobacterium tuberculosis is regarded as one of the most effective treatment options to shorten drug administration regimes, and reduce the opportunity for the emergence of drug resistance. During infection and proliferation, the cytochrome bd oxidase plays a crucial role for mycobacterial pathophysiology by maintaining aerobic respiration at limited oxygen concentrations. Here, we present the cryo-EM structure of the cytochrome bd oxidase from M. tuberculosis at 2.5 Å. In conjunction with atomistic molecular dynamics (MD) simulation studies we discovered a previously unknown MK-9-binding site, as well as a unique disulfide bond within the Q-loop domain that defines an inactive conformation of the canonical quinol oxidation site in Actinobacteria. Our detailed insights into the long-sought atomic framework of the cytochrome bd oxidase from M. tuberculosis will form the basis for the design of highly specific drugs to act on this enzyme.
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Affiliation(s)
- Schara Safarian
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt/Main, Germany.
| | | | - Di Wu
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt/Main, Germany
| | - Ahmad R Mehdipour
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt/Main, Germany
| | - Kiel Hards
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Liam K Harold
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Melanie Radloff
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt/Main, Germany
| | - Ian Stewart
- Department of Chemistry, University of Otago, Dunedin, New Zealand
| | - Sonja Welsch
- Central Electron Microscopy Facility, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt/Main, Germany
- Institute of Biophysics, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Gregory M Cook
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Kurt L Krause
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Hartmut Michel
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt/Main, Germany.
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11
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Cryo-EM structure of mycobacterial cytochrome bd reveals two oxygen access channels. Nat Commun 2021; 12:4621. [PMID: 34330928 PMCID: PMC8324918 DOI: 10.1038/s41467-021-24924-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 07/14/2021] [Indexed: 12/21/2022] Open
Abstract
Cytochromes bd are ubiquitous amongst prokaryotes including many human-pathogenic bacteria. Such complexes are targets for the development of antimicrobial drugs. However, an understanding of the relationship between the structure and functional mechanisms of these oxidases is incomplete. Here, we have determined the 2.8 Å structure of Mycobacterium smegmatis cytochrome bd by single-particle cryo-electron microscopy. This bd oxidase consists of two subunits CydA and CydB, that adopt a pseudo two-fold symmetrical arrangement. The structural topology of its Q-loop domain, whose function is to bind the substrate, quinol, is significantly different compared to the C-terminal region reported for cytochromes bd from Geobacillus thermodenitrificans (G. th) and Escherichia coli (E. coli). In addition, we have identified two potential oxygen access channels in the structure and shown that similar tunnels also exist in G. th and E. coli cytochromes bd. This study provides insights to develop a framework for the rational design of antituberculosis compounds that block the oxygen access channels of this oxidase. Cytochromes bd oxidase (Cyt-bd) catalyzes the reduction of oxygen to water and is the terminal oxidase in the respiratory chain of prokaryotes. Here, the authors present the 2.8 Å cryo-EM structure of Mycobacterium smegmatis Cyt-bd and identify two potential oxygen access channels in the structure, which is of interest for the development of novel antituberculosis drugs.
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12
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Borisov VB. Effect of Membrane Environment on the Ligand-Binding Properties of the Terminal Oxidase Cytochrome bd-I from Escherichia coli. BIOCHEMISTRY (MOSCOW) 2021; 85:1603-1612. [PMID: 33705298 DOI: 10.1134/s0006297920120123] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cytochrome bd-I is a terminal oxidase of the Escherichia coli respiratory chain. This integral membrane protein contains three redox-active prosthetic groups (hemes b558, b595, and d) and couples the electron transfer from quinol to molecular oxygen to the generation of proton motive force, as one of its important physiological functions. The study was aimed at examining the effect of the membrane environment on the ligand-binding properties of cytochrome bd-I by absorption spectroscopy. The membrane environment was found to modulate the ligand-binding characteristics of the hemoprotein in both oxidized and reduced states. Absorption changes upon the addition of exogenous ligands, such as cyanide or carbon monoxide (CO), to the detergent-solubilized enzyme were much more significant and heterogeneous than those observed with the membrane-bound enzyme. In the native membranes, both cyanide and CO interacted mainly with heme d. An additional ligand-binding site (heme b558) appeared in the isolated enzyme, as was evidenced by more pronounced changes in the absorption in the Soret band. This additional reactivity could also be detected after treatment of E. coli membranes with a detergent. The observed effect did not result from the enzyme denaturation, since reconstitution of the isolated enzyme into azolectin liposomes restored the ligand-binding pattern close to that observed for the intact membranes.
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Affiliation(s)
- V B Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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13
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Identification and optimization of quinolone-based inhibitors against cytochrome bd oxidase using an electrochemical assay. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2021.138293] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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14
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Nikolaev A, Safarian S, Thesseling A, Wohlwend D, Friedrich T, Michel H, Kusumoto T, Sakamoto J, Melin F, Hellwig P. Electrocatalytic evidence of the diversity of the oxygen reaction in the bacterial bd oxidase from different organisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148436. [PMID: 33940039 DOI: 10.1016/j.bbabio.2021.148436] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 04/16/2021] [Accepted: 04/21/2021] [Indexed: 11/30/2022]
Abstract
Cytochrome bd oxidase is a bacterial terminal oxygen reductase that was suggested to enable adaptation to different environments and to confer resistance to stress conditions. An electrocatalytic study of the cyt bd oxidases from Escherichia coli, Corynebacterium glutamicum and Geobacillus thermodenitrificans gives evidence for a different reactivity towards oxygen. An inversion of the redox potential values of the three hemes is found when comparing the enzymes from different bacteria. This inversion can be correlated with different protonated glutamic acids as evidenced by reaction induced FTIR spectroscopy. The influence of the microenvironment of the hemes on the reactivity towards oxygen is discussed.
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Affiliation(s)
- Anton Nikolaev
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg - CNRS 4, rue Blaise Pascal, 67081 Strasborg, France
| | - Schara Safarian
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | | | - Daniel Wohlwend
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Hartmut Michel
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Tomoichirou Kusumoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Fukuoka, Japan
| | - Junshi Sakamoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Fukuoka, Japan
| | - Frederic Melin
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg - CNRS 4, rue Blaise Pascal, 67081 Strasborg, France.
| | - Petra Hellwig
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg - CNRS 4, rue Blaise Pascal, 67081 Strasborg, France; USIAS, University of Strasbourg Institute for Advanced Studies, Strasbourg, France.
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15
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Sviriaeva E, Subramanian Manimekalai MS, Grüber G, Pethe K. Features and Functional Importance of Key Residues of the Mycobacterium tuberculosis Cytochrome bd Oxidase. ACS Infect Dis 2020; 6:1697-1707. [PMID: 32379966 DOI: 10.1021/acsinfecdis.9b00449] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome bd (cyt-bd) oxygen reductases have a high affinity to oxygen and use the two electrons provided by ubiquinol or menaquinol, like in mycobacteria, to reduce oxygen to water. Although they do not pump protons from the cytoplasmic to the periplasmic side, they generate a proton motive force due to the release of protons after quinol oxidation. Here, we show that the mycobacterial cyt-bd has a number of specific features, including a 17-residue stretch (307SGVTLQGIRDLQQEYQQ323) near the Q-loop of the Mycobacterium tuberculosis subunit CydA and a 412QLVRLTVKA420 region on the periplasmic side. Site directed mutagenesis and whole-bacteria assays demonstrated that these mycobacteria-specific stretches are essential for the oxidase's function. Single amino acid substitutions around the 307SGVTLQGIRDLQQEYQQ323 stretch revealed the importance of the aromatic residue Y330 in oxygen consumption and consequently in ATP synthesis. A moderate reduction and no effect was observed for mutants F325 and Y321, respectively, while the double mutant CydAY321/F325 drastically reduced enzyme activity. In addition, single mutants of the mycobacterial cyt-bd were generated to probe the role of proposed critical residues for proton shuffling. Further data demonstrate that amino acids W64 and F18 in the CydB subunit might be important as any slight destabilization of the hydrophobic environment near them makes the enzyme inactive. Finally, the potential of the mycobacterial cyt-bd as a drug target is discussed.
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Affiliation(s)
- Ekaterina Sviriaeva
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
- Lee Kong Chian School of Medicine, 59 Nanyang Drive, Singapore 636921, Republic of Singapore
| | | | - Gerhard Grüber
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
| | - Kevin Pethe
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
- Lee Kong Chian School of Medicine, 59 Nanyang Drive, Singapore 636921, Republic of Singapore
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