51
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Calisto F, Sousa FM, Sena FV, Refojo PN, Pereira MM. Mechanisms of Energy Transduction by Charge Translocating Membrane Proteins. Chem Rev 2021; 121:1804-1844. [PMID: 33398986 DOI: 10.1021/acs.chemrev.0c00830] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Life relies on the constant exchange of different forms of energy, i.e., on energy transduction. Therefore, organisms have evolved in a way to be able to harvest the energy made available by external sources (such as light or chemical compounds) and convert these into biological useable energy forms, such as the transmembrane difference of electrochemical potential (Δμ̃). Membrane proteins contribute to the establishment of Δμ̃ by coupling exergonic catalytic reactions to the translocation of charges (electrons/ions) across the membrane. Irrespectively of the energy source and consequent type of reaction, all charge-translocating proteins follow two molecular coupling mechanisms: direct- or indirect-coupling, depending on whether the translocated charge is involved in the driving reaction. In this review, we explore these two coupling mechanisms by thoroughly examining the different types of charge-translocating membrane proteins. For each protein, we analyze the respective reaction thermodynamics, electron transfer/catalytic processes, charge-translocating pathways, and ion/substrate stoichiometries.
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Affiliation(s)
- Filipa Calisto
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipe M Sousa
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipa V Sena
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Patricia N Refojo
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
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52
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Petrik ID, Davydov R, Kahle M, Sandoval B, Dwaraknath S, Ädelroth P, Hoffman B, Lu Y. An Engineered Glutamate in Biosynthetic Models of Heme-Copper Oxidases Drives Complete Product Selectivity by Tuning the Hydrogen-Bonding Network. Biochemistry 2021; 60:346-355. [PMID: 33464878 PMCID: PMC7888536 DOI: 10.1021/acs.biochem.0c00852] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Efficiently carrying out the oxygen reduction reaction (ORR) is critical for many applications in biology and chemistry, such as bioenergetics and fuel cells, respectively. In biology, this reaction is carried out by large, transmembrane oxidases such as heme-copper oxidases (HCOs) and cytochrome bd oxidases. Common to these oxidases is the presence of a glutamate residue next to the active site, but its precise role in regulating the oxidase activity remains unclear. To gain insight into its role, we herein report that incorporation of glutamate next to a designed heme-copper center in two biosynthetic models of HCOs improves O2 binding affinity, facilitates protonation of reaction intermediates, and eliminates release of reactive oxygen species. High-resolution crystal structures of the models revealed extended, water-mediated hydrogen-bonding networks involving the glutamate. Electron paramagnetic resonance of the cryoreduced oxy-ferrous centers at cryogenic temperature followed by thermal annealing allowed observation of the key hydroperoxo intermediate that can be attributed to the hydrogen-bonding network. By demonstrating these important roles of glutamate in oxygen reduction biochemistry, this work offers deeper insights into its role in native oxidases, which may guide the design of more efficient artificial ORR enzymes or catalysts for applications such as fuel cells.
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Affiliation(s)
- Igor D. Petrik
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Roman Davydov
- The Department of Chemistry, Northwestern University, Evanston, Illinois 60201
| | - Maximilian Kahle
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Braddock Sandoval
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Sudharsan Dwaraknath
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Pia Ädelroth
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Brian Hoffman
- The Department of Chemistry, Northwestern University, Evanston, Illinois 60201
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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Hederstedt L. Molecular Biology of Bacillus subtilis Cytochromes anno 2020. BIOCHEMISTRY (MOSCOW) 2021; 86:8-21. [DOI: 10.1134/s0006297921010028] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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54
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Bahuguna A, Rawat S, Rawat DS. QcrB in Mycobacterium tuberculosis: The new drug target of antitubercular agents. Med Res Rev 2021; 41:2565-2581. [PMID: 33400275 DOI: 10.1002/med.21779] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/23/2020] [Accepted: 12/12/2020] [Indexed: 11/08/2022]
Abstract
Drug-resistance in mycobacterial infections is a major global health problem that leads to high mortality and socioeconomic pressure in developing countries around the world. From finding new targets to discovering novel chemical scaffolds, there is an urgent need for the development of better approaches for the cure of tuberculosis. Recently, energy metabolism in mycobacteria, particularly the oxidative phosphorylation pathway of cellular respiration, has emerged as a novel target pathway in drug discovery. New classes of antibacterials which target oxidative phosphorylation pathway either by interacting with a protein or any step in the pathway of oxidative phosphorylation can combat dormant mycobacterial infections leading to shortening of tuberculosis chemotherapy. Adenosine triphosphate synthase is one such recently discovered target of the newly approved antitubercular drug bedaquiline. Cytochrome bcc is another new target of the antitubercular drug candidate Q203, currently in phase II clinical trial. Research suggests that b subunit of cytochrome bcc, QcrB, is the target of Q203. The review article describes the structure, function, and importance of targeting QcrB throwing light on all chemical classes of QcrB inhibitors discovered to date. An understanding of the structure and function of validated targets and their inhibitors would enable the development of new chemical entities.
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Affiliation(s)
| | - Srishti Rawat
- Department of Chemistry, University of Delhi, Delhi, India
| | - Diwan S Rawat
- Department of Chemistry, University of Delhi, Delhi, India
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55
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Kermani AA. A guide to membrane protein X‐ray crystallography. FEBS J 2020; 288:5788-5804. [DOI: 10.1111/febs.15676] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/17/2020] [Accepted: 12/14/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Ali A. Kermani
- Department of Molecular, Cellular, and Developmental Biology University of Michigan Ann Arbor MI USA
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56
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In Escherichia coli Ammonia Inhibits Cytochrome bo3 But Activates Cytochrome bd-I. Antioxidants (Basel) 2020; 10:antiox10010013. [PMID: 33375541 PMCID: PMC7824442 DOI: 10.3390/antiox10010013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 12/14/2022] Open
Abstract
Interaction of two redox enzymes of Escherichia coli, cytochrome bo3 and cytochrome bd-I, with ammonium sulfate/ammonia at pH 7.0 and 8.3 was studied using high-resolution respirometry and absorption spectroscopy. At pH 7.0, the oxygen reductase activity of none of the enzymes is affected by the ligand. At pH 8.3, cytochrome bo3 is inhibited by the ligand, with 40% maximum inhibition at 100 mM (NH4)2SO4. In contrast, the activity of cytochrome bd-I at pH 8.3 increases with increasing the ligand concentration, the largest increase (140%) is observed at 100 mM (NH4)2SO4. In both cases, the effector molecule is apparently not NH4+ but NH3. The ligand induces changes in absorption spectra of both oxidized cytochromes at pH 8.3. The magnitude of these changes increases as ammonia concentration is increased, yielding apparent dissociation constants Kdapp of 24.3 ± 2.7 mM (NH4)2SO4 (4.9 ± 0.5 mM NH3) for the Soret region in cytochrome bo3, and 35.9 ± 7.1 and 24.6 ± 12.4 mM (NH4)2SO4 (7.2 ± 1.4 and 4.9 ± 2.5 mM NH3) for the Soret and visible regions, respectively, in cytochrome bd-I. Consistently, addition of (NH4)2SO4 to cells of the E. coli mutant containing cytochrome bd-I as the only terminal oxidase at pH 8.3 accelerates the O2 consumption rate, the highest one (140%) being at 27 mM (NH4)2SO4. We discuss possible molecular mechanisms and physiological significance of modulation of the enzymatic activities by ammonia present at high concentration in the intestines, a niche occupied by E. coli.
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Bajeli S, Baid N, Kaur M, Pawar GP, Chaudhari VD, Kumar A. Terminal Respiratory Oxidases: A Targetables Vulnerability of Mycobacterial Bioenergetics? Front Cell Infect Microbiol 2020; 10:589318. [PMID: 33330134 PMCID: PMC7719681 DOI: 10.3389/fcimb.2020.589318] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/20/2020] [Indexed: 12/12/2022] Open
Abstract
Recently, ATP synthase inhibitor Bedaquiline was approved for the treatment of multi-drug resistant tuberculosis emphasizing the importance of oxidative phosphorylation for the survival of mycobacteria. ATP synthesis is primarily dependent on the generation of proton motive force through the electron transport chain in mycobacteria. The mycobacterial electron transport chain utilizes two terminal oxidases for the reduction of oxygen, namely the bc1-aa3 supercomplex and the cytochrome bd oxidase. The bc1-aa3 supercomplex is an energy-efficient terminal oxidase that pumps out four vectoral protons, besides consuming four scalar protons during the transfer of electrons from menaquinone to molecular oxygen. In the past few years, several inhibitors of bc1-aa3 supercomplex have been developed, out of which, Q203 belonging to the class of imidazopyridine, has moved to clinical trials. Recently, the crystal structure of the mycobacterial cytochrome bc1-aa3 supercomplex was solved, providing details of the route of transfer of electrons from menaquinone to molecular oxygen. Besides providing insights into the molecular functioning, crystal structure is aiding in the targeted drug development. On the other hand, the second respiratory terminal oxidase of the mycobacterial respiratory chain, cytochrome bd oxidase, does not pump out the vectoral protons and is energetically less efficient. However, it can detoxify the reactive oxygen species and facilitate mycobacterial survival during a multitude of stresses. Quinolone derivatives (CK-2-63) and quinone derivative (Aurachin D) inhibit cytochrome bd oxidase. Notably, ablation of both the two terminal oxidases simultaneously through genetic methods or pharmacological inhibition leads to the rapid death of the mycobacterial cells. Thus, terminal oxidases have emerged as important drug targets. In this review, we have described the current understanding of the functioning of these two oxidases, their physiological relevance to mycobacteria, and their inhibitors. Besides these, we also describe the alternative terminal complexes that are used by mycobacteria to maintain energized membrane during hypoxia and anaerobic conditions.
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Affiliation(s)
- Sapna Bajeli
- Molecular Mycobacteriology, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Navin Baid
- Molecular Mycobacteriology, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Manjot Kaur
- Division of Medicinal Chemistry, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Ganesh P Pawar
- Division of Medicinal Chemistry, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Vinod D Chaudhari
- Division of Medicinal Chemistry, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
| | - Ashwani Kumar
- Molecular Mycobacteriology, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India
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58
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Layer G. Heme biosynthesis in prokaryotes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118861. [PMID: 32976912 DOI: 10.1016/j.bbamcr.2020.118861] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/21/2022]
Abstract
The cyclic tetrapyrrole heme is used as a prosthetic group in a broad variety of different proteins in almost all organisms. Often, it is essential for vital biochemical processes such as aerobic and anaerobic respiration as well as photosynthesis. In Nature, heme is made from the common tetrapyrrole precursor 5-aminolevulinic acid, and for a long time it was assumed that heme is biosynthesized by a single, common pathway in all organisms. However, although this is indeed the case in eukaryotes, heme biosynthesis is more diverse in the prokaryotic world, where two additional pathways exist. The final elucidation of the two 'alternative' heme biosynthesis routes operating in some bacteria and archaea was achieved within the last decade. This review summarizes the three different heme biosynthesis pathways with a special emphasis on the two 'new' prokaryotic routes.
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Affiliation(s)
- Gunhild Layer
- Albert-Ludwigs-Universität Freiburg, Institut für Pharmazeutische Wissenschaften, Stefan-Meier-Strasse 19, 79104 Freiburg, Germany.
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59
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Melin F, Hellwig P. Redox Properties of the Membrane Proteins from the Respiratory Chain. Chem Rev 2020; 120:10244-10297. [DOI: 10.1021/acs.chemrev.0c00249] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Frederic Melin
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
| | - Petra Hellwig
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
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60
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Beam JP, Becraft ED, Brown JM, Schulz F, Jarett JK, Bezuidt O, Poulton NJ, Clark K, Dunfield PF, Ravin NV, Spear JR, Hedlund BP, Kormas KA, Sievert SM, Elshahed MS, Barton HA, Stott MB, Eisen JA, Moser DP, Onstott TC, Woyke T, Stepanauskas R. Ancestral Absence of Electron Transport Chains in Patescibacteria and DPANN. Front Microbiol 2020; 11:1848. [PMID: 33013724 PMCID: PMC7507113 DOI: 10.3389/fmicb.2020.01848] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/15/2020] [Indexed: 12/21/2022] Open
Abstract
Recent discoveries suggest that the candidate superphyla Patescibacteria and DPANN constitute a large fraction of the phylogenetic diversity of Bacteria and Archaea. Their small genomes and limited coding potential have been hypothesized to be ancestral adaptations to obligate symbiotic lifestyles. To test this hypothesis, we performed cell-cell association, genomic, and phylogenetic analyses on 4,829 individual cells of Bacteria and Archaea from 46 globally distributed surface and subsurface field samples. This confirmed the ubiquity and abundance of Patescibacteria and DPANN in subsurface environments, the small size of their genomes and cells, and the divergence of their gene content from other Bacteria and Archaea. Our analyses suggest that most Patescibacteria and DPANN in the studied subsurface environments do not form specific physical associations with other microorganisms. These data also suggest that their unusual genomic features and prevalent auxotrophies may be a result of ancestral, minimal cellular energy transduction mechanisms that lack respiration, thus relying solely on fermentation for energy conservation.
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Affiliation(s)
- Jacob P Beam
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Eric D Becraft
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Julia M Brown
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Frederik Schulz
- Department of Energy Joint Genome Institute, Berkeley, CA, United States
| | - Jessica K Jarett
- Department of Energy Joint Genome Institute, Berkeley, CA, United States
| | - Oliver Bezuidt
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Nicole J Poulton
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Kayla Clark
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Peter F Dunfield
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Nikolai V Ravin
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - John R Spear
- Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
| | - Brian P Hedlund
- School of Life Sciences - Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Konstantinos A Kormas
- Department of Ichthyology and Aquatic Environment, University of Thessaly, Volos, Greece
| | - Stefan M Sievert
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Mostafa S Elshahed
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States
| | - Hazel A Barton
- Department of Biology, University of Akron, Akron, OH, United States
| | - Matthew B Stott
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Jonathan A Eisen
- Department of Evolution and Ecology, Department of Medical Microbiology and Immunology, Genome Center, University of California, Davis, Davis, CA, United States
| | - Duane P Moser
- Desert Research Institute, Las Vegas, NV, United States
| | - Tullis C Onstott
- Department of Geosciences, Princeton University, Princeton, NJ, United States
| | - Tanja Woyke
- Department of Energy Joint Genome Institute, Berkeley, CA, United States
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61
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Skin Bacteria Mediate Glycerol Fermentation to Produce Electricity and Resist UV-B. Microorganisms 2020; 8:microorganisms8071092. [PMID: 32708352 PMCID: PMC7409288 DOI: 10.3390/microorganisms8071092] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/19/2020] [Accepted: 07/19/2020] [Indexed: 12/22/2022] Open
Abstract
Bacteria that use electron transport proteins in the membrane to produce electricity in the gut microbiome have been identified recently. However, the identification of electrogenic bacteria in the skin microbiome is almost completely unexplored. Using a ferric iron-based ferrozine assay, we have identified the skin Staphylococcus epidermidis (S. epidermidis) as an electrogenic bacterial strain. Glycerol fermentation was essential for the electricity production of S. epidermidis since the inhibition of fermentation by 5-methyl furfural (5-MF) significantly diminished the bacterial electricity measured by voltage changes in a microbial fuel cell (MFC). A small-scale chamber with both anode and cathode was fabricated in order to study the effect of ultraviolet-B (UV-B) on electricity production and bacterial resistance to UV-B. Although UV-B lowered bacterial electricity, a prolonged incubation of S. epidermidis in the presence of glycerol promoted fermentation and elicited higher electricity to suppress the effect of UV-B. Furthermore, the addition of glycerol into S. epidermidis enhanced bacterial resistance to UV-B. Electricity produced by human skin commensal bacteria may be used as a dynamic biomarker to reflect the UV radiation in real-time.
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Elamri I, Radloff M, Hohmann KF, Nimbarte VD, Nasiri HR, Bolte M, Safarian S, Michel H, Schwalbe H. Synthesis and Biological Screening of New Lawson Derivatives as Selective Substrate-Based Inhibitors of Cytochrome bo 3 Ubiquinol Oxidase from Escherichia coli. ChemMedChem 2020; 15:1262-1271. [PMID: 32159929 PMCID: PMC7497249 DOI: 10.1002/cmdc.201900707] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/20/2020] [Indexed: 01/13/2023]
Abstract
The respiratory chain of Escherichia coli contains two different types of terminal oxidase that are differentially regulated as a response to changing environmental conditions. These oxidoreductases catalyze the reduction of molecular oxygen to water and contribute to the proton motive force. The cytochrome bo3 oxidase (cyt bo3 ) acts as the primary terminal oxidase under atmospheric oxygen levels, whereas the bd-type oxidase is most abundant under microaerobic conditions. In E. coli, both types of respiratory terminal oxidase (HCO and bd-type) use ubiquinol-8 as electron donor. Here, we assess the inhibitory potential of newly designed and synthesized 3-alkylated Lawson derivatives through L-proline-catalyzed three-component reductive alkylation (TCRA). The inhibitory effects of these Lawson derivatives on the terminal oxidases of E. coli (cyt bo3 and cyt bd-I) were tested potentiometrically. Four compounds were able to reduce the oxidoreductase activity of cyt bo3 by more than 50 % without affecting the cyt bd-I activity. Moreover, two inhibitors for both cyt bo3 and cyt bd-I oxidase could be identified. Based on molecular-docking simulations, we propose binding modes of the new Lawson inhibitors. The molecular fragment benzyl enhances the inhibitory potential and selectivity for cyt bo3 , whereas heterocycles reduce this effect. This work extends the library of 3-alkylated Lawson derivatives as selective inhibitors for respiratory oxidases and provides molecular probes for detailed investigations of the mechanisms of respiratory-chain enzymes of E. coli.
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Affiliation(s)
- Isam Elamri
- Center for Biomolecular Magnetic Resonance Institute of Organic Chemistry and Chemical BiologyGoethe-Universität Frankfurt am MainMax-von Laue-Straße 760438Frankfurt am MainGermany
| | - Melanie Radloff
- Department of Molecular Membrane BiologyMax Planck Institute of BiophysicsMax-von-Laue-Straße 360438Frankfurt am MainGermany
| | - Katharina F. Hohmann
- Center for Biomolecular Magnetic Resonance Institute of Organic Chemistry and Chemical BiologyGoethe-Universität Frankfurt am MainMax-von Laue-Straße 760438Frankfurt am MainGermany
| | - Vijaykumar D. Nimbarte
- Center for Biomolecular Magnetic Resonance Institute of Organic Chemistry and Chemical BiologyGoethe-Universität Frankfurt am MainMax-von Laue-Straße 760438Frankfurt am MainGermany
| | - Hamid R. Nasiri
- Center for Biomolecular Magnetic Resonance Institute of Organic Chemistry and Chemical BiologyGoethe-Universität Frankfurt am MainMax-von Laue-Straße 760438Frankfurt am MainGermany
| | - Michael Bolte
- Institute for Inorganic ChemistryGoethe-UniversitätFrankfurt am MainGermany
| | - Schara Safarian
- Department of Molecular Membrane BiologyMax Planck Institute of BiophysicsMax-von-Laue-Straße 360438Frankfurt am MainGermany
| | - Hartmut Michel
- Department of Molecular Membrane BiologyMax Planck Institute of BiophysicsMax-von-Laue-Straße 360438Frankfurt am MainGermany
| | - Harald Schwalbe
- Center for Biomolecular Magnetic Resonance Institute of Organic Chemistry and Chemical BiologyGoethe-Universität Frankfurt am MainMax-von Laue-Straße 760438Frankfurt am MainGermany
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63
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Nikolaev A, Makarchuk I, Thesseling A, Hoeser J, Friedrich T, Melin F, Hellwig P. Stabilization of the Highly Hydrophobic Membrane Protein, Cytochrome bd Oxidase, on Metallic Surfaces for Direct Electrochemical Studies. Molecules 2020; 25:molecules25143240. [PMID: 32708635 PMCID: PMC7397230 DOI: 10.3390/molecules25143240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/08/2020] [Accepted: 07/14/2020] [Indexed: 11/23/2022] Open
Abstract
The cytochrome bd oxidase catalyzes the reduction of oxygen to water in bacteria and it is thus an interesting target for electrocatalytic studies and biosensor applications. The bd oxidase is completely embedded in the phospholipid membrane. In this study, the variation of the surface charge of thiol-modified gold nanoparticles, the length of the thiols and the other crucial parameters including optimal phospholipid content and type, have been performed, giving insight into the role of these factors for the optimal interaction and direct electron transfer of an integral membrane protein. Importantly, all three tested factors, the lipid type, the electrode surface charge and the thiol length mutually influenced the stability of films of the cytochrome bd oxidase. The best electrocatalytic responses were obtained on the neutral gold surface when the negatively charged phosphatidylglycerol (PG) was used and on the charged gold surface when the zwitterionic phosphatidylethanolamine (PE) was used. The advantages of the covalent binding of the membrane protein to the electrode surface over the non-covalent binding are also discussed.
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Affiliation(s)
- Anton Nikolaev
- Laboratoire de Bioelectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg, CNRS, 67081 Strasbourg, France; (A.N.); (I.M.)
| | - Iryna Makarchuk
- Laboratoire de Bioelectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg, CNRS, 67081 Strasbourg, France; (A.N.); (I.M.)
| | - Alexander Thesseling
- Institut für Biochemie, Fakultät für Chemie und Pharmazie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany; (A.T.); (J.H.); (T.F.)
| | - Jo Hoeser
- Institut für Biochemie, Fakultät für Chemie und Pharmazie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany; (A.T.); (J.H.); (T.F.)
| | - Thorsten Friedrich
- Institut für Biochemie, Fakultät für Chemie und Pharmazie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany; (A.T.); (J.H.); (T.F.)
| | - Frédéric Melin
- Laboratoire de Bioelectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg, CNRS, 67081 Strasbourg, France; (A.N.); (I.M.)
- Correspondence: (F.M.); (P.H.)
| | - Petra Hellwig
- Laboratoire de Bioelectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg, CNRS, 67081 Strasbourg, France; (A.N.); (I.M.)
- Correspondence: (F.M.); (P.H.)
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Abstract
Manganese is among Earth’s most abundant elements. Its oxidation had long been theorized1, yet undemonstrated2–4, to fuel chemolithoautotrophic microbial growth. Here, an enrichment culture exhibiting Mn(II)-oxidation-dependent, exponential growth was refined to a two species co-culture. Oxidation required viable bacteria at permissive temperatures, resulting in the generation of small Mn oxide nodules to which the cells associated. The majority member of the culture, ‘Candidatus Manganitrophus noduliformans’, affiliates within phylum Nitrospirae (Nitrospirota) but is distantly related to known Nitrospira and Leptospirillum species. The minority member has been isolated, but does not oxidise Mn(II) alone. Stable isotope probing revealed Mn(II)-oxidation-dependent, 13CO2-fixation into cellular biomass. Transcriptomics reveals candidate pathways for coupling extracellular manganese oxidation to aerobic energy conservation and to autotrophic CO2-fixation. These findings expand the known diversity of inorganic metabolisms supporting life, while completing a biogeochemical energy cycle for manganese5,6, one that may interface with other major global elemental cycles.
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65
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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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Exploration of Electrochemcially Active Bacterial Strains for Microbial Fuel Cells: An Innovation in Bioelectricity Generation. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2020. [DOI: 10.22207/jpam.14.1.12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Oxidative Phosphorylation—an Update on a New, Essential Target Space for Drug Discovery in Mycobacterium tuberculosis. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10072339] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
New drugs with new mechanisms of action are urgently required to tackle the global tuberculosis epidemic. Following the FDA-approval of the ATP synthase inhibitor bedaquiline (Sirturo®), energy metabolism has become the subject of intense focus as a novel pathway to exploit for tuberculosis drug development. This enthusiasm stems from the fact that oxidative phosphorylation (OxPhos) and the maintenance of the transmembrane electrochemical gradient are essential for the viability of replicating and non-replicating Mycobacterium tuberculosis (M. tb), the etiological agent of human tuberculosis (TB). Therefore, new drugs targeting this pathway have the potential to shorten TB treatment, which is one of the major goals of TB drug discovery. This review summarises the latest and key findings regarding the OxPhos pathway in M. tb and provides an overview of the inhibitors targeting various components. We also discuss the potential of new regimens containing these inhibitors, the flexibility of this pathway and, consequently, the complexity in targeting it. Lastly, we discuss opportunities and future directions of this drug target space.
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68
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Orr MW, Mao Y, Storz G, Qian SB. Alternative ORFs and small ORFs: shedding light on the dark proteome. Nucleic Acids Res 2020; 48:1029-1042. [PMID: 31504789 DOI: 10.1093/nar/gkz734] [Citation(s) in RCA: 146] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/03/2019] [Accepted: 08/15/2019] [Indexed: 02/06/2023] Open
Abstract
Traditional annotation of protein-encoding genes relied on assumptions, such as one open reading frame (ORF) encodes one protein and minimal lengths for translated proteins. With the serendipitous discoveries of translated ORFs encoded upstream and downstream of annotated ORFs, from alternative start sites nested within annotated ORFs and from RNAs previously considered noncoding, it is becoming clear that these initial assumptions are incorrect. The findings have led to the realization that genetic information is more densely coded and that the proteome is more complex than previously anticipated. As such, interest in the identification and characterization of the previously ignored 'dark proteome' is increasing, though we note that research in eukaryotes and bacteria has largely progressed in isolation. To bridge this gap and illustrate exciting findings emerging from studies of the dark proteome, we highlight recent advances in both eukaryotic and bacterial cells. We discuss progress in the detection of alternative ORFs as well as in the understanding of functions and the regulation of their expression and posit questions for future work.
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Affiliation(s)
- Mona Wu Orr
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Yuanhui Mao
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
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Lee BS, Sviriaeva E, Pethe K. Targeting the cytochrome oxidases for drug development in mycobacteria. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 152:45-54. [PMID: 32081616 DOI: 10.1016/j.pbiomolbio.2020.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 01/15/2020] [Accepted: 02/06/2020] [Indexed: 11/19/2022]
Abstract
Mycobacterium tuberculosis strictly depends on oxygen to multiply, and the terminal oxidases are a vital part of the oxidative phosphorylation pathway. The bacterium possesses two aerobic respiratory branches: a cytochrome bcc-aa3 and a bacteria-specific cytochrome bd oxidase. The identification of small-molecule inhibitors of the cytochrome bcc-aa3 under numerous experimental conditions reflects the essentiality of the pathway for the optimum growth of M. tuberculosis. Recent findings on the biology of the cytochrome bcc-aa3 as well as the report of the first high-resolution structure of a mycobacterial cytochrome bcc-aa3 complex will help in the characterization and further development of potent inhibitors. Although the aerobic cytochrome bd respiratory branch is not strictly essential for growth, the discovery of a strong synthetic lethal interaction with the cytochrome bcc-aa3 placed the cytochrome bd oxidase under the spotlight as an attractive drug target for its synergistic role in potentiating the efficacy of cytochrome bcc-aa3 inhibitors and other drugs targeting oxidative phosphorylation. In this review, we are discussing current knowledge about the two mycobacterial aerobic respiratory branches, their potential as drug targets, as well as potential drawbacks.
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Affiliation(s)
- Bei Shi Lee
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Ekaterina Sviriaeva
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Kevin Pethe
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, 636921, Singapore.
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Theßeling A, Burschel S, Wohlwend D, Friedrich T. The long Q‐loop ofEscherichia colicytochromebdoxidase is required for assembly and structural integrity. FEBS Lett 2020; 594:1577-1585. [DOI: 10.1002/1873-3468.13749] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/24/2020] [Accepted: 01/26/2020] [Indexed: 11/08/2022]
Affiliation(s)
| | - Sabrina Burschel
- Institut für Biochemie Albert‐Ludwigs‐Universität Freiburg Germany
| | - Daniel Wohlwend
- Institut für Biochemie Albert‐Ludwigs‐Universität Freiburg Germany
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Goojani HG, Konings J, Hakvoort H, Hong S, Gennis RB, Sakamoto J, Lill H, Bald D. The carboxy-terminal insert in the Q-loop is needed for functionality of Escherichia coli cytochrome bd-I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148175. [PMID: 32061652 DOI: 10.1016/j.bbabio.2020.148175] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 01/24/2020] [Accepted: 02/10/2020] [Indexed: 12/27/2022]
Abstract
Cytochrome bd, a component of the prokaryotic respiratory chain, is important under physiological stress and during pathogenicity. Electrons from quinol substrates are passed on via heme groups in the CydA subunit and used to reduce molecular oxygen. Close to the quinol binding site, CydA displays a periplasmic hydrophilic loop called Q-loop that is essential for quinol oxidation. In the carboxy-terminal part of this loop, CydA from Escherichia coli and other proteobacteria harbors an insert of ~60 residues with unknown function. In the current work, we demonstrate that growth of the multiple-deletion strain E. coli MB43∆cydA (∆cydA∆cydB∆appB∆cyoB∆nuoB) can be enhanced by transformation with E. coli cytochrome bd-I and we utilize this system for assessment of Q-loop mutants. Deletion of the cytochrome bd-I Q-loop insert abolished MB43∆cydA growth recovery. Swapping the cytochrome bd-I Q-loop for the Q-loop from Geobacillus thermodenitrificans or Mycobacterium tuberculosis CydA, which lack the insert, did not enhance the growth of MB43∆cydA, whereas swapping for the Q-loop from E. coli cytochrome bd-II recovered growth. Alanine scanning experiments identified the cytochrome bd-I Q-loop insert regions Ile318-Met322, Gln338-Asp342, Tyr353-Leu357, and Thr368-Ile372 as important for enzyme functionality. Those mutants that completely failed to recover growth of MB43∆cydA also lacked oxygen consumption activity and heme absorption peaks. Moreover, we were not able to isolate cytochrome bd-I from these inactive mutants. The results indicate that the cytochrome bd Q-loop exhibits low plasticity and that the Q-loop insert in E. coli is needed for complete, stable, assembly of cytochrome bd-I.
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Affiliation(s)
- Hojjat Ghasemi Goojani
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Julia Konings
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Henk Hakvoort
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Sangjin Hong
- Department of Biochemistry, University of Illinois, 600 S. Mathews Avenue, Urbana, IL 61801, United States
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, 600 S. Mathews Avenue, Urbana, IL 61801, United States
| | - Junshi Sakamoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka-ken 820-8502, Japan
| | - Holger Lill
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, the Netherlands.
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Harikishore A, Chong SSM, Ragunathan P, Bates RW, Grüber G. Targeting the menaquinol binding loop of mycobacterial cytochrome bd oxidase. Mol Divers 2020; 25:517-524. [PMID: 31939065 DOI: 10.1007/s11030-020-10034-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/06/2020] [Indexed: 12/27/2022]
Abstract
Mycobacteria have shown enormous resilience to survive and persist by remodeling and altering metabolic requirements. Under stringent conditions or exposure to drugs, mycobacteria have adapted to rescue themselves by shutting down their major metabolic activity and elevate certain survival factor levels and efflux pathways to survive and evade the effects of drug treatments. A fundamental feature in this adaptation is the ability of mycobacteria to vary the enzyme composition of the electron transport chain (ETC), which generates the proton motive force for the synthesis of adenosine triphosphate via oxidative phosphorylation. Mycobacteria harbor dehydrogenases to fuel the ETC, and two terminal respiratory oxidases, an aa3-type cytochrome c oxidase (cyt-bcc-aa3) and a bacterial specific cytochrome bd-type menaquinol oxidase (cyt-bd). In this study, we employed homology modeling and structure-based virtual screening studies to target mycobacteria-specific residues anchoring the b558 menaquinol binding region of Mycobacterium tuberculosis cyt-bd oxidase to obtain a focused library. Furthermore, ATP synthesis inhibition assays were carried out. One of the ligands MQL-H2 inhibited both NADH2- and succinate-driven ATP synthesis inhibition of Mycobacterium smegmatis inside-out vesicles in micromolar potency. Similarly, MQL-H2 also inhibited NADH2-driven ATP synthesis in inside-out vesicles of the cytochrome-bcc oxidase deficient M. smegmatis strain. Since neither varying the electron donor substrates nor deletion of the cyt-bcc oxidase, a major source of protons, hindered the inhibitory effects of the MQL-H2, reflecting that MQL-H2 targets the terminal oxidase cytochrome bd oxidase, which was consistent with molecular docking studies. Characterization of novel cytochrome bd oxidase Menaquinol binding domain inhibitor (MQL-H2) using virtual screening and ATP synthesis inhibition assays.
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Affiliation(s)
- Amaravadhi Harikishore
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Republic of Singapore
| | - Sherilyn Shi Min Chong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Republic of Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore
- Nanyang Institute of Technology in Health and Medicine, Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Republic of Singapore
| | - Priya Ragunathan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore
| | - Roderick W Bates
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Republic of Singapore
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore.
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The Small Protein CydX Is Required for Cytochrome bd Quinol Oxidase Stability and Function in Salmonella enterica Serovar Typhimurium: a Phenotypic Study. J Bacteriol 2020; 202:JB.00348-19. [PMID: 31659011 DOI: 10.1128/jb.00348-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 10/21/2019] [Indexed: 01/12/2023] Open
Abstract
Cytochrome bd quinol oxidases, which have a greater affinity for oxygen than heme-copper cytochrome oxidases (HCOs), promote bacterial respiration and fitness in low-oxygen environments, such as host tissues. Here, we show that, in addition to the CydA and CydB subunits, the small protein CydX is required for the assembly and function of the cytochrome bd complex in the enteric pathogen Salmonella enterica serovar Typhimurium. Mutant S Typhimurium lacking CydX showed a loss of proper heme arrangement and impaired oxidase activity comparable to that of a ΔcydABX mutant lacking all cytochrome bd subunits. Moreover, both the ΔcydX mutant and the ΔcydABX mutant showed increased sensitivity to β-mercaptoethanol and nitric oxide (NO). Cytochrome bd-mediated protection from β-mercaptoethanol was not a result of resistance to reducing damage but, rather, was due to cytochrome bd oxidase managing Salmonella respiration, while β-mercaptoethanol interacted with the copper ions necessary for the HCO activity of the cytochrome bo-type quinol oxidase. Interactions between NO and hemes in cytochrome bd and cytochrome bd-dependent respiration during nitrosative stress indicated a direct role for cytochrome bd in mediating Salmonella resistance to NO. Additionally, CydX was required for S Typhimurium proliferation inside macrophages. Mutants deficient in cytochrome bd, however, showed a significant increase in resistance to antibiotics, including aminoglycosides, d-cycloserine, and ampicillin. The essential role of CydX in cytochrome bd assembly and function suggests that targeting this small protein could be a useful antimicrobial strategy, but potential drug tolerance responses should also be considered.IMPORTANCE Cytochrome bd quinol oxidases, which are found only in bacteria, govern the fitness of many facultative anaerobic pathogens by promoting respiration in low-oxygen environments and by conferring resistance to antimicrobial radicals. Thus, cytochrome bd complex assembly and activity are considered potential therapeutic targets. Here we report that the small protein CydX is required for the assembly and function of the cytochrome bd complex in S Typhimurium under stress conditions, including exposure to β-mercaptoethanol, nitric oxide, or the phagocytic intracellular environment, demonstrating its crucial function for Salmonella fitness. However, cytochrome bd inactivation also leads to increased resistance to some antibiotics, so considerable caution should be taken when developing therapeutic strategies targeting the CydX-dependent cytochrome bd.
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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.
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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
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75
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Mascolo L, Bald D. Cytochrome bd in Mycobacterium tuberculosis: A respiratory chain protein involved in the defense against antibacterials. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 152:55-63. [PMID: 31738981 DOI: 10.1016/j.pbiomolbio.2019.11.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/12/2019] [Indexed: 12/27/2022]
Abstract
The branched respiratory chain of Mycobacterium tuberculosis has attracted attention as a highly promising target for next-generation antibacterials. This system includes two terminal oxidases of which the exclusively bacterial cytochrome bd represents the less energy-efficient one. Albeit dispensable for growth under standard laboratory conditions, cytochrome bd is important during environmental stress. In this review, we discuss the role of cytochrome bd during infection of the mammalian host and in the defense against antibacterials. Deeper insight into the biochemistry of mycobacterial cytochrome bd is needed to understand the physiological role of this bacteria-specific defense factor. Conversely, cytochrome bd may be utilized to gain information on mycobacterial physiology in vitro and during host infection. Knowledge-based manipulation of cytochrome bd function may assist in designing the next-generation tuberculosis combination chemotherapy.
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Affiliation(s)
- Ludovica Mascolo
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
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Borisov VB, Siletsky SA. Features of Organization and Mechanism of Catalysis of Two Families of Terminal Oxidases: Heme-Copper and bd-Type. BIOCHEMISTRY (MOSCOW) 2019; 84:1390-1402. [DOI: 10.1134/s0006297919110130] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Homologous bd oxidases share the same architecture but differ in mechanism. Nat Commun 2019; 10:5138. [PMID: 31723136 PMCID: PMC6853902 DOI: 10.1038/s41467-019-13122-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/22/2019] [Indexed: 11/25/2022] Open
Abstract
Cytochrome bd oxidases are terminal reductases of bacterial and archaeal respiratory chains. The enzyme couples the oxidation of ubiquinol or menaquinol with the reduction of dioxygen to water, thus contributing to the generation of the protonmotive force. Here, we determine the structure of the Escherichia coli bd oxidase treated with the specific inhibitor aurachin by cryo-electron microscopy (cryo-EM). The major subunits CydA and CydB are related by a pseudo two fold symmetry. The heme b and d cofactors are found in CydA, while ubiquinone-8 is bound at the homologous positions in CydB to stabilize its structure. The architecture of the E. coli enzyme is highly similar to that of Geobacillus thermodenitrificans, however, the positions of heme b595 and d are interchanged, and a common oxygen channel is blocked by a fourth subunit and substituted by a more narrow, alternative channel. Thus, with the same overall fold, the homologous enzymes exhibit a different mechanism. Cytochrome bd oxidases couple quinol oxidation and the release of protons to the periplasmic side with proton uptake from the cytoplasmic side to reduce dioxygen to water and they are the terminal reductases in bacterial and archaeal respiratory chains. Here the authors present the cryo-EM structure of Escherichia coli bd oxidase and discuss mechanistic implications.
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In the respiratory chain of Escherichia coli cytochromes bd-I and bd-II are more sensitive to carbon monoxide inhibition than cytochrome bo 3. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:148088. [PMID: 31669488 DOI: 10.1016/j.bbabio.2019.148088] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 09/27/2019] [Accepted: 10/18/2019] [Indexed: 11/23/2022]
Abstract
Bacteria can not only encounter carbon monoxide (CO) in their habitats but also produce the gas endogenously. Bacterial respiratory oxidases, thus, represent possible targets for CO. Accordingly, host macrophages were proposed to produce CO and release it into the surrounding microenvironment to sense viable bacteria through a mechanism that in Escherichia (E.) coli was suggested to involve the targeting of a bd-type respiratory oxidase by CO. The aerobic respiratory chain of E. coli possesses three terminal quinol:O2-oxidoreductases: the heme-copper oxidase bo3 and two copper-lacking bd-type oxidases, bd-I and bd-II. Heme-copper and bd-type oxidases differ in the mechanism and efficiency of proton motive force generation and in resistance to oxidative and nitrosative stress, cyanide and hydrogen sulfide. Here, we investigated at varied O2 concentrations the effect of CO gas on the O2 reductase activity of the purified cytochromes bo3, bd-I and bd-II of E. coli. We found that CO, in competition with O2, reversibly inhibits the three enzymes. The inhibition constants Ki for the bo3, bd-I and bd-II oxidases are 2.4 ± 0.3, 0.04 ± 0.01 and 0.2 ± 0.1 μM CO, respectively. Thus, in E. coli, bd-type oxidases are more sensitive to CO inhibition than the heme-copper cytochrome bo3. The possible physiological consequences of this finding are discussed.
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Cordero PRF, Grinter R, Hards K, Cryle MJ, Warr CG, Cook GM, Greening C. Two uptake hydrogenases differentially interact with the aerobic respiratory chain during mycobacterial growth and persistence. J Biol Chem 2019; 294:18980-18991. [PMID: 31624148 DOI: 10.1074/jbc.ra119.011076] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/12/2019] [Indexed: 12/11/2022] Open
Abstract
To persist when nutrient sources are limited, aerobic soil bacteria metabolize atmospheric hydrogen (H2). This process is the primary sink in the global H2 cycle and supports the productivity of microbes in oligotrophic environments. H2-metabolizing bacteria possess [NiFe] hydrogenases that oxidize H2 to subatmospheric concentrations. The soil saprophyte Mycobacterium smegmatis has two such [NiFe] hydrogenases, designated Huc and Hhy, that belong to different phylogenetic subgroups. Both Huc and Hhy are oxygen-tolerant, oxidize H2 to subatmospheric concentrations, and enhance bacterial survival during hypoxia and carbon limitation. Why does M. smegmatis require two hydrogenases with a seemingly similar function? In this work, we resolved this question by showing that Huc and Hhy are differentially expressed, localized, and integrated into the respiratory chain. Huc is active in late exponential and early stationary phases, supporting energy conservation during mixotrophic growth and transition into dormancy. In contrast, Hhy is most active during long-term persistence, providing energy for maintenance processes following carbon exhaustion. We also show that Huc and Hhy are obligately linked to the aerobic respiratory chain via the menaquinone pool and are differentially affected by respiratory uncouplers. Consistently, these two enzymes interacted differentially with the respiratory terminal oxidases. Huc exclusively donated electrons to, and possibly physically associated with, the proton-pumping cytochrome bcc-aa 3 supercomplex. In contrast the more promiscuous Hhy also provided electrons to the cytochrome bd oxidase complex. These results indicate that, despite their similar characteristics, Huc and Hhy perform distinct functions during mycobacterial growth and survival.
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Affiliation(s)
- Paul R F Cordero
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Rhys Grinter
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Kiel Hards
- Department of Microbiology and Immunology, University of Otago, Dunedin, OTA 9016, New Zealand
| | - Max J Cryle
- Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Coral G Warr
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia.,School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, OTA 9016, New Zealand
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
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80
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Safarian S, Hahn A, Mills DJ, Radloff M, Eisinger ML, Nikolaev A, Meier-Credo J, Melin F, Miyoshi H, Gennis RB, Sakamoto J, Langer JD, Hellwig P, Kühlbrandt W, Michel H. Active site rearrangement and structural divergence in prokaryotic respiratory oxidases. Science 2019; 366:100-104. [DOI: 10.1126/science.aay0967] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 09/04/2019] [Indexed: 12/30/2022]
Abstract
Cytochrome bd–type quinol oxidases catalyze the reduction of molecular oxygen to water in the respiratory chain of many human-pathogenic bacteria. They are structurally unrelated to mitochondrial cytochrome c oxidases and are therefore a prime target for the development of antimicrobial drugs. We determined the structure of theEscherichia colicytochrome bd-I oxidase by single-particle cryo–electron microscopy to a resolution of 2.7 angstroms. Our structure contains a previously unknown accessory subunit CydH, the L-subfamily–specific Q-loop domain, a structural ubiquinone-8 cofactor, an active-site density interpreted as dioxygen, distinct water-filled proton channels, and an oxygen-conducting pathway. Comparison with another cytochrome bd oxidase reveals structural divergence in the family, including rearrangement of high-spin hemes and conformational adaption of a transmembrane helix to generate a distinct oxygen-binding site.
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Affiliation(s)
- S. Safarian
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
| | - A. Hahn
- Department of Structural Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
| | - D. J. Mills
- Department of Structural Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
| | - M. Radloff
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
| | - M. L. Eisinger
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
| | - A. Nikolaev
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg-CNRS, 67000 Strasbourg, France
| | - J. Meier-Credo
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
| | - F. Melin
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg-CNRS, 67000 Strasbourg, France
| | - H. Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - R. B. Gennis
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - J. Sakamoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka-ken 820-8502, Japan
| | - J. D. Langer
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
| | - P. Hellwig
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg-CNRS, 67000 Strasbourg, France
- University of Strasbourg Institute for Advanced Study, Strasbourg, France
| | - W. Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
| | - H. Michel
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, D-60438 Frankfurt/Main, Germany
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81
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Martins MC, Romão CV, Folgosa F, Borges PT, Frazão C, Teixeira M. How superoxide reductases and flavodiiron proteins combat oxidative stress in anaerobes. Free Radic Biol Med 2019; 140:36-60. [PMID: 30735841 DOI: 10.1016/j.freeradbiomed.2019.01.051] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/14/2019] [Accepted: 01/31/2019] [Indexed: 12/31/2022]
Abstract
Microbial anaerobes are exposed in the natural environment and in their hosts, even if transiently, to fluctuating concentrations of oxygen and its derived reactive species, which pose a considerable threat to their anoxygenic lifestyle. To counteract these stressful conditions, they contain a multifaceted array of detoxifying systems that, in conjugation with cellular repairing mechanisms and in close crosstalk with metal homeostasis, allow them to survive in the presence of O2 and reactive oxygen species. Some of these systems are shared with aerobes, but two families of enzymes emerged more recently that, although not restricted to anaerobes, are predominant in anaerobic microbes. These are the iron-containing superoxide reductases, and the flavodiiron proteins, endowed with O2 and/or NO reductase activities, which are the subject of this Review. A detailed account of their physicochemical, physiological and molecular mechanisms will be presented, highlighting their unique properties in allowing survival of anaerobes in oxidative stress conditions, and comparing their properties with the most well-known detoxifying systems.
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Affiliation(s)
- Maria C Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Célia V Romão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Filipe Folgosa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Patrícia T Borges
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Miguel Teixeira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.
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82
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Poole RK, Cozens AG, Shepherd M. The CydDC family of transporters. Res Microbiol 2019; 170:407-416. [PMID: 31279084 DOI: 10.1016/j.resmic.2019.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/12/2019] [Accepted: 06/25/2019] [Indexed: 12/23/2022]
Abstract
The CydDC family of ABC transporters export the low molecular weight thiols glutathione and cysteine to the periplasm of a variety of bacterial species. The CydDC complex has previously been shown to be important for disulfide folding, motility, respiration, and tolerance to nitric oxide and antibiotics. In addition, CydDC is thus far unique amongst ABC transporters in that it binds a haem cofactor that appears to modulate ATPase activity. CydDC has a diverse impact upon bacterial metabolism, growth, and virulence, and is of interest to those working on membrane transport mechanisms, redox biology, aerobic respiration, and stress sensing/tolerance during infection.
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Affiliation(s)
- Robert K Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
| | - Adam G Cozens
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Mark Shepherd
- School of Biosciences, University of Kent, Canterbury, United Kingdom.
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83
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Versantvoort W, Pol A, Daumann LJ, Larrabee JA, Strayer AH, Jetten MS, van Niftrik L, Reimann J, Op den Camp HJ. Characterization of a novel cytochrome c as the electron acceptor of XoxF-MDH in the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:595-603. [DOI: 10.1016/j.bbapap.2019.04.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 03/28/2019] [Accepted: 04/02/2019] [Indexed: 11/29/2022]
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84
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Extracellular electron transfer features of Gram-positive bacteria. Anal Chim Acta 2019; 1076:32-47. [PMID: 31203962 DOI: 10.1016/j.aca.2019.05.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/23/2019] [Accepted: 05/05/2019] [Indexed: 12/20/2022]
Abstract
Electroactive microorganisms possess the unique ability to transfer electrons to or from solid phase electron conductors, e.g., electrodes or minerals, through various physiological mechanisms. The processes are commonly known as extracellular electron transfer and broadly harnessed in microbial electrochemical systems, such as microbial biosensors, microbial electrosynthesis, or microbial fuel cells. Apart from a few model microorganisms, the nature of the microbe-electrode conductive interaction is poorly understood for most of the electroactive species. The interaction determines the efficiency and a potential scaling up of bioelectrochemical systems. Gram-positive bacteria generally have a thick electron non-conductive cell wall and are believed to exhibit weak extracellular electron shuttling activity. This review highlights reported research accomplishments on electroactive Gram-positive bacteria. The use of electron-conducting polymers as mediators is considered as one promising strategy to enhance the electron transfer efficiency up to application scale. In view of the recent progress in understanding the molecular aspects of the extracellular electron transfer mechanisms of Enterococcus faecalis, the electron transfer properties of this bacterium are especially focused on. Fundamental knowledge on the nature of microbial extracellular electron transfer and its possibilities can provide insight in interspecies electron transfer and biogeochemical cycling of elements in nature. Additionally, a comprehensive understanding of cell-electrode interactions may help in overcoming insufficient electron transfer and restricted operational performance of various bioelectrochemical systems and facilitate their practical applications.
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85
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Beebout CJ, Eberly AR, Werby SH, Reasoner SA, Brannon JR, De S, Fitzgerald MJ, Huggins MM, Clayton DB, Cegelski L, Hadjifrangiskou M. Respiratory Heterogeneity Shapes Biofilm Formation and Host Colonization in Uropathogenic Escherichia coli. mBio 2019; 10:e02400-18. [PMID: 30940709 PMCID: PMC6445943 DOI: 10.1128/mbio.02400-18] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/25/2019] [Indexed: 12/22/2022] Open
Abstract
Biofilms are multicellular bacterial communities encased in a self-secreted extracellular matrix comprised of polysaccharides, proteinaceous fibers, and DNA. Organization of these components lends spatial organization to the biofilm community such that biofilm residents can benefit from the production of common goods while being protected from exogenous insults. Spatial organization is driven by the presence of chemical gradients, such as oxygen. Here we show that two quinol oxidases found in Escherichia coli and other bacteria organize along the biofilm oxygen gradient and that this spatially coordinated expression controls architectural integrity. Cytochrome bd, a high-affinity quinol oxidase required for aerobic respiration under hypoxic conditions, is the most abundantly expressed respiratory complex in the biofilm community. Depletion of the cytochrome bd-expressing subpopulation compromises biofilm complexity by reducing the abundance of secreted extracellular matrix as well as increasing cellular sensitivity to exogenous stresses. Interrogation of the distribution of quinol oxidases in the planktonic state revealed that ∼15% of the population expresses cytochrome bd at atmospheric oxygen concentration, and this population dominates during acute urinary tract infection. These data point toward a bet-hedging mechanism in which heterogeneous expression of respiratory complexes ensures respiratory plasticity of E. coli across diverse host niches.IMPORTANCE Biofilms are multicellular bacterial communities encased in a self-secreted extracellular matrix comprised of polysaccharides, proteinaceous fibers, and DNA. Organization of these components lends spatial organization in the biofilm community. Here we demonstrate that oxygen gradients in uropathogenic Escherichia coli (UPEC) biofilms lead to spatially distinct expression programs for quinol oxidases-components of the terminal electron transport chain. Our studies reveal that the cytochrome bd-expressing subpopulation is critical for biofilm development and matrix production. In addition, we show that quinol oxidases are heterogeneously expressed in planktonic populations and that this respiratory heterogeneity provides a fitness advantage during infection. These studies define the contributions of quinol oxidases to biofilm physiology and suggest the presence of respiratory bet-hedging behavior in UPEC.
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Affiliation(s)
- Connor J Beebout
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Allison R Eberly
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sabrina H Werby
- Department of Chemistry, Stanford University, Stanford, California, USA
| | - Seth A Reasoner
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - John R Brannon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Shuvro De
- Division of Pediatric Urology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | | | - Douglass B Clayton
- Division of Pediatric Urology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, Stanford, California, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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86
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Degli Esposti M, Mentel M, Martin W, Sousa FL. Oxygen Reductases in Alphaproteobacterial Genomes: Physiological Evolution From Low to High Oxygen Environments. Front Microbiol 2019; 10:499. [PMID: 30936856 PMCID: PMC6431628 DOI: 10.3389/fmicb.2019.00499] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 02/27/2019] [Indexed: 01/24/2023] Open
Abstract
Oxygen reducing terminal oxidases differ with respect to their subunit composition, heme groups, operon structure, and affinity for O2. Six families of terminal oxidases are currently recognized, all of which occur in alphaproteobacterial genomes, two of which are also present in mitochondria. Many alphaproteobacteria encode several different terminal oxidases, likely reflecting ecological versatility with respect to oxygen levels. Terminal oxidase evolution likely started with the advent of O2 roughly 2.4 billion years ago and terminal oxidases diversified in the Proterozoic, during which oxygen levels remained low, around the Pasteur point (ca. 2 μM O2). Among the alphaproteobacterial genomes surveyed, those from members of the Rhodospirillaceae reveal the greatest diversity in oxygen reductases. Some harbor all six terminal oxidase types, in addition to many soluble enzymes typical of anaerobic fermentations in mitochondria and hydrogenosomes of eukaryotes. Recent data have it that O2 levels increased to current values (21% v/v or ca. 250 μM) only about 430 million years ago. Ecological adaptation brought forth different lineages of alphaproteobacteria and different lineages of eukaryotes that have undergone evolutionary specialization to high oxygen, low oxygen, and anaerobic habitats. Some have remained facultative anaerobes that are able to generate ATP with or without the help of oxygen and represent physiological links to the ancient proteobacterial lineage at the origin of mitochondria and eukaryotes. Our analysis reveals that the genomes of alphaproteobacteria appear to retain signatures of ancient transitions in aerobic metabolism, findings that are relevant to mitochondrial evolution in eukaryotes as well.
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Affiliation(s)
| | - Marek Mentel
- Faculty of Natural Sciences, Department of Biochemistry, Comenius University in Bratislava, Bratislava, Slovakia
| | - William Martin
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Filipa L Sousa
- Division of Archaea Biology and Ecogenomics, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
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87
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Galván AE, Chalón MC, Ríos Colombo NS, Schurig-Briccio LA, Sosa-Padilla B, Gennis RB, Bellomio A. Microcin J25 inhibits ubiquinol oxidase activity of purified cytochrome bd-I from Escherichia coli. Biochimie 2019; 160:141-147. [PMID: 30790617 DOI: 10.1016/j.biochi.2019.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 02/14/2019] [Indexed: 11/28/2022]
Abstract
Microcin J25 (MccJ25), an antimicrobial peptide, targets the respiratory chain but the exact mechanism by which it does so remains unclear. Here, we reveal that MccJ25 is able to inhibit the enzymatic activity of the isolated cytochrome bd-I from E. coli and induces at the same time production of reactive oxygen species. MccJ25 behaves as a dose-dependent weak inhibitor. Intriguingly, MccJ25 is capable of producing a change in the oxidation state of cytochrome bd-I causing its partial reduction in the presence of cyanide. These effects are specific for cytochrome bd-I, since the peptide is not able to act on purified cytochrome bo3.
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Affiliation(s)
- Adriana Emilce Galván
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) e Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Chacabuco 461, San Miguel de Tucumán, Argentina
| | - Miriam Carolina Chalón
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) e Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Chacabuco 461, San Miguel de Tucumán, Argentina
| | - Natalia Soledad Ríos Colombo
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) e Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Chacabuco 461, San Miguel de Tucumán, Argentina
| | | | - Bernardo Sosa-Padilla
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET), Avenida Belgrano y Pasaje Caseros, T4001MVB, Tucumán, Argentina
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, Urbana, IL, 61801, USA
| | - Augusto Bellomio
- Instituto Superior de Investigaciones Biológicas (INSIBIO, CONICET-UNT) e Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Chacabuco 461, San Miguel de Tucumán, Argentina.
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88
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The compound TB47 is highly bactericidal against Mycobacterium ulcerans in a Buruli ulcer mouse model. Nat Commun 2019; 10:524. [PMID: 30705268 PMCID: PMC6355801 DOI: 10.1038/s41467-019-08464-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 12/19/2018] [Indexed: 11/16/2022] Open
Abstract
Buruli ulcer (BU) is an emerging infectious disease that causes disfiguring skin ulcers. The causative agent, Mycobacterium ulcerans, secretes toxin called mycolactone that triggers inflammation and immunopathology. Existing treatments are lengthy and consist of drugs developed for tuberculosis. Here, we report that a pyrazolo[1,5-a]pyridine-3-carboxamide, TB47, is highly bactericidal against M. ulcerans both in vitro and in vivo. In the validated mouse model of BU, TB47 alone reduces M. ulcerans burden in mouse footpads by more than 2.5 log10 CFU compared to the standard BU treatment regimen recommended by the WHO. We show that mutations of ubiquinol-cytochrome C reductase cytochrome subunit B confer resistance to TB47 and the dissimilarity of CydABs from different mycobacteria may account for their differences in susceptibility to TB47. TB47 is highly potent against M. ulcerans and possesses desirable pharmacological attributes and low toxicity that warrant further assessment of this agent for treatment of BU. Combination therapy for Buruli ulcer (BU) is suboptimal. Here, Liu et al. show that the candidate drug TB47 has potent bactericidal activity against Mycobacterium ulcerans in vitro and in a mouse model, which underscores its potential for shortening the course of BU and treating other mycobacterial diseases.
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89
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Manoj KM, Parashar A, David Jacob V, Ramasamy S. Aerobic respiration: proof of concept for the oxygen-centric murburn perspective. J Biomol Struct Dyn 2019; 37:4542-4556. [PMID: 30488771 DOI: 10.1080/07391102.2018.1552896] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The inner mitochondrial membrane protein complexes (I-V) and prokaryotic respiratory machinery are examined for a deeper understanding of their structure-function correlations and dynamics. In silico analysis of the structure of complexes I-IV, docking studies and erstwhile literature confirm that they carry sites which are in close proximity to DROS (diffusible reactive oxygen species) generating redox centers. These findings provide supportive evidence for the newly proposed oxygen-centric chemical-coupling mechanism (murburn concept), wherein DROS catalyzes the esterification of inorganic phosphate to ADP. Further, in a reductionist system, we demonstrate that a DROS (like superoxide) can effectively esterify inorganic phosphate to ADP. The impact of these findings and the interactive dynamics of classical inhibitors (rotenone and cyanide), uncouplers (dinitrophenol and uncoupling protein) and other toxins (atractyloside and oligomycin) are briefly discussed. Highlights • Earlier perception: Complexes (I-IV) pump protons and Complex V make ATP (aided by protons) • Herein: Respiratory molecular machinery is probed for new structure-function correlations • Analyses: Quantitative arguments discount proton-centric ATP synthesis in mitochondria and bacteria • In silico data: ADP-binding sites and O2/ diffusible reactive oxygen species (DROS)-accessible channels are unveiled in respiratory proteins • In vitro data: Using luminometry, ATP synthesis is demonstrated from ADP, Pi and superoxide • Inference: Findings agree with decentralized ADP-Pi activation via oxygen-centric murburn scheme Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | - Abhinav Parashar
- Department of Biotechnology, Vignan's Foundation for Science, Technology & Research , Vadlamudi , Guntur, Andhra Pradesh, India
| | | | - Surjith Ramasamy
- Department of Biotechnology, Indian Institute of Technology Guwahati , Guwahati , Assam, India
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90
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Muras V, Toulouse C, Fritz G, Steuber J. Respiratory Membrane Protein Complexes Convert Chemical Energy. Subcell Biochem 2019; 92:301-335. [PMID: 31214991 DOI: 10.1007/978-3-030-18768-2_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The invention of a biological membrane which is used as energy storage system to drive the metabolism of a primordial, unicellular organism represents a key event in the evolution of life. The innovative, underlying principle of this key event is respiration. In respiration, a lipid bilayer with insulating properties is chosen as the site for catalysis of an exergonic redox reaction converting substrates offered from the environment, using the liberated Gibbs free energy (ΔG) for the build-up of an electrochemical H+ (proton motive force, PMF) or Na+ gradient (sodium motive force, SMF) across the lipid bilayer. Very frequently , several redox reactions are performed in a consecutive manner, with the first reaction delivering a product which is used as substrate for the second redox reaction, resulting in a respiratory chain. From today's perspective, the (mostly) unicellular bacteria and archaea seem to be much simpler and less evolved when compared to multicellular eukaryotes. However, they are overwhelmingly complex with regard to the various respiratory chains which permit survival in very different habitats of our planet, utilizing a plethora of substances to drive metabolism. This includes nitrogen, sulfur and carbon compounds which are oxidized or reduced by specialized, respiratory enzymes of bacteria and archaea which lie at the heart of the geochemical N, S and C-cycles. This chapter gives an overview of general principles of microbial respiration considering thermodynamic aspects, chemical reactions and kinetic restraints. The respiratory chains of Escherichia coli and Vibrio cholerae are discussed as models for PMF- versus SMF-generating processes, respectively. We introduce main redox cofactors of microbial respiratory enzymes, and the concept of intra-and interelectron transfer. Since oxygen is an electron acceptor used by many respiratory chains, the formation and removal of toxic oxygen radicals is described. Promising directions of future research are respiratory enzymes as novel bacterial targets, and biotechnological applications relying on respiratory complexes.
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Affiliation(s)
- Valentin Muras
- Institute of Microbiology, University of Hohenheim, Garbenstr. 30, 70599, Stuttgart, Germany
| | - Charlotte Toulouse
- Institute of Microbiology, University of Hohenheim, Garbenstr. 30, 70599, Stuttgart, Germany
| | - Günter Fritz
- Institute of Microbiology, University of Hohenheim, Garbenstr. 30, 70599, Stuttgart, Germany
| | - Julia Steuber
- Institute of Microbiology, University of Hohenheim, Garbenstr. 30, 70599, Stuttgart, Germany.
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91
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Teixeira MH, Arantes GM. Effects of lipid composition on membrane distribution and permeability of natural quinones. RSC Adv 2019; 9:16892-16899. [PMID: 35516391 PMCID: PMC9064471 DOI: 10.1039/c9ra01681c] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/20/2019] [Indexed: 11/21/2022] Open
Abstract
Lipid acyl chain unsaturation modulates the barrier for ubiquinone flip-flop over the membrane.
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Affiliation(s)
- Murilo Hoias Teixeira
- Department of Biochemistry
- Instituto de Química
- Universidade de São Paulo
- São Paulo
- Brazil
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92
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Taylor AJ, Kelly DJ. The function, biogenesis and regulation of the electron transport chains in Campylobacter jejuni: New insights into the bioenergetics of a major food-borne pathogen. Adv Microb Physiol 2019; 74:239-329. [PMID: 31126532 DOI: 10.1016/bs.ampbs.2019.02.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Campylobacter jejuni is a zoonotic Epsilonproteobacterium that grows in the gastrointestinal tract of birds and mammals, and is the most frequent cause of food-borne bacterial gastroenteritis worldwide. As an oxygen-sensitive microaerophile, C. jejuni has to survive high environmental oxygen tensions, adapt to oxygen limitation in the host intestine and resist host oxidative attack. Despite its small genome size, C. jejuni is a versatile and metabolically active pathogen, with a complex and highly branched set of respiratory chains allowing the use of a wide range of electron donors and alternative electron acceptors in addition to oxygen, including fumarate, nitrate, nitrite, tetrathionate and N- or S-oxides. Several novel enzymes participate in these electron transport chains, including a tungsten containing formate dehydrogenase, a Complex I that uses flavodoxin and not NADH, a periplasmic facing fumarate reductase and a cytochrome c tetrathionate reductase. This review presents an updated description of the composition and bioenergetics of these various respiratory chains as they are currently understood, including recent work that gives new insights into energy conservation during electron transport to various alternative electron acceptors. The regulation of synthesis and assembly of the electron transport chains is also discussed. A deeper appreciation of the unique features of the respiratory systems of C. jejuni may be helpful in informing strategies to control this important pathogen.
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Affiliation(s)
- Aidan J Taylor
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David J Kelly
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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93
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Duarte AG, Catarino T, White GF, Lousa D, Neukirchen S, Soares CM, Sousa FL, Clarke TA, Pereira IAC. An electrogenic redox loop in sulfate reduction reveals a likely widespread mechanism of energy conservation. Nat Commun 2018; 9:5448. [PMID: 30575735 PMCID: PMC6303296 DOI: 10.1038/s41467-018-07839-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/27/2018] [Indexed: 02/02/2023] Open
Abstract
The bioenergetics of anaerobic metabolism frequently relies on redox loops performed by membrane complexes with substrate- and quinone-binding sites on opposite sides of the membrane. However, in sulfate respiration (a key process in the biogeochemical sulfur cycle), the substrate- and quinone-binding sites of the QrcABCD complex are periplasmic, and their role in energy conservation has not been elucidated. Here we show that the QrcABCD complex of Desulfovibrio vulgaris is electrogenic, as protons and electrons required for quinone reduction are extracted from opposite sides of the membrane, with a H+/e− ratio of 1. Although the complex does not act as a H+-pump, QrcD may include a conserved proton channel leading from the N-side to the P-side menaquinone pocket. Our work provides evidence of how energy is conserved during dissimilatory sulfate reduction, and suggests mechanisms behind the functions of related bacterial respiratory complexes in other bioenergetic contexts. The bacterial complex QrcABCD plays a key role in the bioenergetics of sulfate respiration. Here, Duarte et al. show that this complex is electrogenic, with protons and electrons required for quinone reduction being extracted from opposite sides of the membrane.
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Affiliation(s)
- Américo G Duarte
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Teresa Catarino
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.,Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal
| | - Gaye F White
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Diana Lousa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Sinje Neukirchen
- Division of Archaea Biology and Ecogenomics, Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14 UZA I, 1090, Vienna, Austria
| | - Cláudio M Soares
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Filipa L Sousa
- Division of Archaea Biology and Ecogenomics, Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14 UZA I, 1090, Vienna, Austria
| | - Thomas A Clarke
- Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Inês A C Pereira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.
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94
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Cytochrome bd Oxidase Has an Important Role in Sustaining Growth and Development of Streptomyces coelicolor A3(2) under Oxygen-Limiting Conditions. J Bacteriol 2018; 200:JB.00239-18. [PMID: 29784883 DOI: 10.1128/jb.00239-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/14/2018] [Indexed: 11/20/2022] Open
Abstract
Streptomyces coelicolor A3(2) is a filamentously growing, spore-forming, obligately aerobic actinobacterium that uses both a copper aa3 -type cytochrome c oxidase and a cytochrome bd oxidase to respire oxygen. Using defined knockout mutants, we demonstrated that either of these terminal oxidases was capable of allowing the bacterium to grow and complete its developmental cycle. The genes encoding the bcc complex and the aa3 oxidase are clustered at a single locus. Using Western blot analyses, we showed that the bcc-aa3 oxidase branch is more prevalent in spores than the bd oxidase. The level of the catalytic subunit, CydA, of the bd oxidase was low in spore extracts derived from the wild type, but it was upregulated in a mutant lacking the bcc-aa3 supercomplex. This indicates that cytochrome bd oxidase can compensate for the lack of the other respiratory branch. Components of both oxidases were abundant in growing mycelium. Growth studies in liquid medium revealed that a mutant lacking the bcc-aa3 oxidase branch grew approximately half as fast as the wild type, while the oxygen reduction rate of the mutant remained close to that of the wild type, indicating that the bd oxidase was mainly functioning in controlling electron flux. Developmental defects were observed for a mutant lacking the cytochrome bd oxidase during growth on buffered rich medium plates with glucose as the energy substrate. Evidence based on using the redox-cycling dye methylene blue suggested that cytochrome bd oxidase is essential for the bacterium to grow and complete its developmental cycle under oxygen limitation.IMPORTANCE Respiring with oxygen is an efficient means of conserving energy in biological systems. The spore-forming, filamentous actinobacterium Streptomyces coelicolor grows only aerobically, synthesizing two enzyme complexes for O2 reduction, the cytochrome bcc-aa3 cytochrome oxidase supercomplex and the cytochrome bd oxidase. We show in this study that the bacterium can survive with either of these respiratory pathways to oxygen. Immunological studies indicate that the bcc-aa3 oxidase is the main oxidase present in spores, but the bd oxidase compensates if the bcc-aa3 oxidase is inactivated. Both oxidases are active in mycelia. Growth conditions were identified, revealing that cytochrome bd oxidase is essential for aerial hypha formation and sporulation, and this was linked to an important role of the enzyme under oxygen-limiting conditions.
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95
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Pankratova G, Leech D, Gorton L, Hederstedt L. Extracellular Electron Transfer by the Gram-Positive Bacterium Enterococcus faecalis. Biochemistry 2018; 57:4597-4603. [DOI: 10.1021/acs.biochem.8b00600] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Galina Pankratova
- Department of Biochemistry and Structural Biology, Lund University, SE-22100 Lund, Sweden
| | - Dónal Leech
- School of Chemistry and Ryan Institute, National University of Ireland Galway, University Road, Galway, Ireland
| | - Lo Gorton
- Department of Biochemistry and Structural Biology, Lund University, SE-22100 Lund, Sweden
| | - Lars Hederstedt
- The Microbiology Group, Department of Biology, Lund University, Sölvegatan 35, SE-22362 Lund, Sweden
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96
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Murali R, Gennis RB. Functional importance of Glutamate-445 and Glutamate-99 in proton-coupled electron transfer during oxygen reduction by cytochrome bd from Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:577-590. [PMID: 29719208 DOI: 10.1016/j.bbabio.2018.04.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/25/2018] [Accepted: 04/26/2018] [Indexed: 12/27/2022]
Abstract
The recent X-ray structure of the cytochrome bd respiratory oxygen reductase showed that two of the three heme components, heme d and heme b595, have glutamic acid as an axial ligand. No other native heme proteins are known to have glutamic acid axial ligands. In this work, site-directed mutagenesis is used to probe the roles of these glutamic acids, E445 and E99 in the E. coli enzyme. It is concluded that neither glutamate is a strong ligand to the heme Fe and they are not the major determinates of heme binding to the protein. Although very important, neither glutamate is absolutely essential for catalytic function. The close interactions between the three hemes in cyt bd result in highly cooperative properties. For example, mutation of E445, which is near heme d, has its greatest effects on the properties of heme b595 and heme b558. It is concluded that 1) O2 binds to the hydrophilic side of heme d and displaces E445; 2) E445 forms a salt bridge with R448 within the O2 binding pocket, and both residues play a role to stabilize oxygenated states of heme d during catalysis; 3) E445 and E99 are each protonated accompanying electron transfer to heme d and heme b595, respectively; 4) All protons used to generate water within the heme d active site come from the cytoplasm and are delivered through a channel that must include internal water molecules to assist proton transfer: [cytoplasm] → E107 → E99 (heme b595) → E445 (heme d) → oxygenated heme d.
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Affiliation(s)
- Ranjani Murali
- Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA.
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97
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Siletsky SA, Dyuba AV, Elkina DA, Monakhova MV, Borisov VB. Spectral-Kinetic Analysis of Recombination Reaction of Heme Centers of bd-Type Quinol Oxidase from Escherichia coli with Carbon Monoxide. BIOCHEMISTRY (MOSCOW) 2018; 82:1354-1366. [PMID: 29223162 DOI: 10.1134/s000629791711013x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recombination of the isolated, fully reduced bd-type quinol oxidase from Escherichia coli with carbon monoxide was studied by pulsed absorption spectrophotometry with microsecond time resolution. Analysis of the kinetic phases of recombination was carried out using the global analysis of multiwavelength kinetic data ("Global fitting"). It was found that the unresolved photodissociation of CO is followed by a stepwise (with four phases) recombination with characteristic times (τ) of about 20 µs, 250 µs, 1.1 ms, and 24 ms. The 20-µs phase most likely reflects bimolecular recombination of CO with heme d. Two subsequent kinetic transitions, with τ ~ 250 µs and 1.1 ms, were resolved for the first time. It is assumed that the 250-µs phase is heterogeneous and includes two different processes: recombination of CO with ~7% of heme b595 and transition of heme d from a pentacoordinate to a transient hexacoordinate state in this enzyme population. The 24-ms transition probably reflects a return of heme d to the pentacoordinate state in the same protein fraction. The 1.1-ms phase can be explained by recombination of CO with ~15% of heme b558. Possible models of interaction of CO with different heme centers are discussed.
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Affiliation(s)
- S A Siletsky
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119991, Russia.
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98
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Duval M, Cossart P. Small bacterial and phagic proteins: an updated view on a rapidly moving field. Curr Opin Microbiol 2017; 39:81-88. [PMID: 29111488 DOI: 10.1016/j.mib.2017.09.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/17/2017] [Indexed: 01/21/2023]
Abstract
Small proteins, that is, polypeptides of 50 amino acids (aa) or less, are increasingly recognized as important regulators in bacteria. Secreted or not, their small size make them versatile proteins, involved in a wide range of processes. They may allow bacteria to sense and to respond to stresses, to send signals and communicate, and to modulate infections. Bacteriophages also produce small proteins to influence lysogeny/lysis decisions. In this review, we update the present view on small proteins functions, and discuss their possible applications.
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Affiliation(s)
- Mélodie Duval
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Paris F-75015, France; Institut National de la Santé et de la Recherche Médicale, U604, Paris F-75015, France; Institut National de la Recherche Agronomique, Unité Sous Contrat 2020, Paris F-75015, France.
| | - Pascale Cossart
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Paris F-75015, France; Institut National de la Santé et de la Recherche Médicale, U604, Paris F-75015, France; Institut National de la Recherche Agronomique, Unité Sous Contrat 2020, Paris F-75015, France.
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99
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Boot M, Jim KK, Liu T, Commandeur S, Lu P, Verboom T, Lill H, Bitter W, Bald D. A fluorescence-based reporter for monitoring expression of mycobacterial cytochrome bd in response to antibacterials and during infection. Sci Rep 2017; 7:10665. [PMID: 28878275 PMCID: PMC5587683 DOI: 10.1038/s41598-017-10944-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 08/16/2017] [Indexed: 12/16/2022] Open
Abstract
Cytochrome bd is a component of the oxidative phosphorylation pathway in many Gram-positive and Gram-negative bacteria. Next to its role as a terminal oxidase in the respiratory chain this enzyme plays an important role as a survival factor in the bacterial stress response. In Mycobacterium tuberculosis and related mycobacterial strains, cytochrome bd is an important component of the defense system against antibacterial drugs. In this report we describe and evaluate an mCherry-based fluorescent reporter for detection of cytochrome bd expression in Mycobacterium marinum. Cytochrome bd was induced by mycolic acid biosynthesis inhibitors such as isoniazid and most prominently by drugs targeting oxidative phosphorylation. We observed no induction by inhibitors of protein-, DNA- or RNA-synthesis. The constructed expression reporter was suitable for monitoring mycobacterial cytochrome bd expression during mouse macrophage infection and in a zebrafish embryo infection model when using Mycobacterium marinum. Interestingly, in both these infection models cytochrome bd levels were considerably higher than during in vitro culturing of M. marinum. The expression reporter described here can be a valuable tool for elucidating the role of cytochrome bd as a survival factor.
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Affiliation(s)
- Maikel Boot
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Kin Ki Jim
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Ting Liu
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Susanna Commandeur
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Ping Lu
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Theo Verboom
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Holger Lill
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.,Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, Amsterdam Institute for Molecules, Medicines and Systems, Faculty of Earth- and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
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100
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Computational studies of membrane proteins: from sequence to structure to simulation. Curr Opin Struct Biol 2017; 45:133-141. [DOI: 10.1016/j.sbi.2017.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 04/07/2017] [Accepted: 04/07/2017] [Indexed: 11/19/2022]
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