1
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Zhang L, Einsle O. Architecture of the RNF1 complex that drives biological nitrogen fixation. Nat Chem Biol 2024; 20:1078-1085. [PMID: 38890433 DOI: 10.1038/s41589-024-01641-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 05/10/2024] [Indexed: 06/20/2024]
Abstract
Biological nitrogen fixation requires substantial metabolic energy in form of ATP as well as low-potential electrons that must derive from central metabolism. During aerobic growth, the free-living soil diazotroph Azotobacter vinelandii transfers electrons from the key metabolite NADH to the low-potential ferredoxin FdxA that serves as a direct electron donor to the dinitrogenase reductases. This process is mediated by the RNF complex that exploits the proton motive force over the cytoplasmic membrane to lower the midpoint potential of the transferred electron. Here we report the cryogenic electron microscopy structure of the nitrogenase-associated RNF complex of A. vinelandii, a seven-subunit membrane protein assembly that contains four flavin cofactors and six iron-sulfur centers. Its function requires the strict coupling of electron and proton transfer but also involves major conformational changes within the assembly that can be traced with a combination of electron microscopy and modeling.
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Affiliation(s)
- Lin Zhang
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Oliver Einsle
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.
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2
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Hu Y, Yuan M, Julian A, Tuz K, Juárez O. Identification of complex III, NQR, and SDH as primary bioenergetic enzymes during the stationary phase of Pseudomonas aeruginosa cultured in urine-like conditions. Front Microbiol 2024; 15:1347466. [PMID: 38468849 PMCID: PMC10926992 DOI: 10.3389/fmicb.2024.1347466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/08/2024] [Indexed: 03/13/2024] Open
Abstract
Pseudomonas aeruginosa is a common cause of urinary tract infections by strains that are often multidrug resistant, representing a major challenge to the world's health care system. This microorganism has a highly adaptable metabolism that allows it to colonize many environments, including the urinary tract. In this work, we have characterized the metabolic strategies used by stationary phase P. aeruginosa cells cultivated in urine-like media to understand the adaptations used by this microorganism to survive and produce disease. Our proteomics results show that cells rely on the Entner-Duodoroff pathway, pentose phosphate pathway, the Krebs cycle/ glyoxylate shunt and the aerobic oxidative phosphorylation to survive in urine-like media and other conditions. A deep characterization of the oxidative phosphorylation showed that the respiratory rate of stationary phase cells is increased 3-4 times compared to cells in the logarithmic phase of growth, indicating that the aerobic metabolism plays critical roles in the stationary phase of cells grown in urine like media. Moreover, the data show that respiratory complex III, succinate dehydrogenase and the NADH dehydrogenase NQR have important functions and could be used as targets to develop new antibiotics against this bacterium.
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Affiliation(s)
| | | | | | | | - Oscar Juárez
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL, United States
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3
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Baothman OAS. Identifying therapeutic antibacterial peptides against Vibrio cholerae to inhibit the function of Na(+)-translocating NADH-quinone reductase. J Biomol Struct Dyn 2023:1-16. [PMID: 37850460 DOI: 10.1080/07391102.2023.2270696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 10/07/2023] [Indexed: 10/19/2023]
Abstract
Vibrio cholerae is the bacteria responsible for cholera, which is a significant threat to many nations. Curing and treating this infection requires identification of the critical protein and development of a drug to inhibit its function. In this context, Na(+)-translocating NADH-quinone reductase was considered a potential therapeutic target. A library of antibacterial peptides with residue lengths of 50 was screened using a docking method, and the five most potent peptides were selected on the basis of a weighted score derived from solvent accessible surface area and docking score. To investigate the stability of the protein-peptide complex, a 100-ns molecular dynamics simulation was performed. These peptides targeted the native dimeric binding interface of Na(+)-transporting NADH-quinone reductase. This study evaluated the binding affinity and conformational stability of these peptides with the protein using different post-simulation metrics. A peptide, CCL28, exhibited steady RMSD characteristics; nonetheless, it modified the docked conformation but stabilized in the new conformation. This peptide also demonstrated the best performance in addressing the protein's native binding interface. It demonstrated a binding free energy of -120 kcal/mol with the protein. Principal component analysis (PCA) revealed that the first PC had the lowest conformational variation and the greatest coverage. Eventually, these peptides were also evaluated using steered molecular dynamics, and it was discovered that CCL28 had a greater maximum force than the other five peptides, at 1139.08 kJ/mol/nm. Targeting the native binding interface, we present a CCL28 peptide with a strong potential to block the biological activity of Vibrio cholerae's Na(+)-translocating NADH-quinone reductase.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Othman A S Baothman
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
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4
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Sit B, Srisuknimit V, Bueno E, Zingl FG, Hullahalli K, Cava F, Waldor MK. Undecaprenyl phosphate translocases confer conditional microbial fitness. Nature 2023; 613:721-728. [PMID: 36450355 PMCID: PMC9876793 DOI: 10.1038/s41586-022-05569-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 11/17/2022] [Indexed: 12/05/2022]
Abstract
The microbial cell wall is essential for maintenance of cell shape and resistance to external stressors1. The primary structural component of the cell wall is peptidoglycan, a glycopolymer with peptide crosslinks located outside of the cell membrane1. Peptidoglycan biosynthesis and structure are responsive to shifting environmental conditions such as pH and salinity2-6, but the mechanisms underlying such adaptations are incompletely understood. Precursors of peptidoglycan and other cell surface glycopolymers are synthesized in the cytoplasm and then delivered across the cell membrane bound to the recyclable lipid carrier undecaprenyl phosphate7 (C55-P, also known as UndP). Here we identify the DUF368-containing and DedA transmembrane protein families as candidate C55-P translocases, filling a critical gap in knowledge of the proteins required for the biogenesis of microbial cell surface polymers. Gram-negative and Gram-positive bacteria lacking their cognate DUF368-containing protein exhibited alkaline-dependent cell wall and viability defects, along with increased cell surface C55-P levels. pH-dependent synthetic genetic interactions between DUF368-containing proteins and DedA family members suggest that C55-P transporter usage is dynamic and modulated by environmental inputs. C55-P transporter activity was required by the cholera pathogen for growth and cell shape maintenance in the intestine. We propose that conditional transporter reliance provides resilience in lipid carrier recycling, bolstering microbial fitness both inside and outside the host.
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Affiliation(s)
- Brandon Sit
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Veerasak Srisuknimit
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA.,Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Emilio Bueno
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Franz G Zingl
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Karthik Hullahalli
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA.,Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden.
| | - Matthew K Waldor
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA. .,Department of Microbiology, Harvard Medical School, Boston, MA, USA. .,Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA. .,Howard Hughes Medical Institute, Bethesda, MD, USA.
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5
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Purification and structural characterization of the Na +-translocating ferredoxin: NAD + reductase (Rnf) complex of Clostridium tetanomorphum. Nat Commun 2022; 13:6315. [PMID: 36274063 PMCID: PMC9588780 DOI: 10.1038/s41467-022-34007-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/05/2022] [Indexed: 12/25/2022] Open
Abstract
Various microbial metabolisms use H+/Na+-translocating ferredoxin:NAD+ reductase (Rnf) either to exergonically oxidize reduced ferredoxin by NAD+ for generating a transmembrane electrochemical potential or reversely to exploit the latter for producing reduced ferredoxin. For cryo-EM structural analysis, we elaborated a quick four-step purification protocol for the Rnf complex from Clostridium tetanomorphum and integrated the homogeneous and active enzyme into a nanodisc. The obtained 4.27 Å density map largely allows chain tracing and redox cofactor identification complemented by biochemical data from entire Rnf and single subunits RnfB, RnfC and RnfG. On this basis, we postulated an electron transfer route between ferredoxin and NAD via eight [4Fe-4S] clusters, one Fe ion and four flavins crossing the cell membrane twice related to the pathway of NADH:ubiquinone reductase. Redox-coupled Na+ translocation is provided by orchestrating Na+ uptake/release, electrostatic effects of the assumed membrane-integrated FMN semiquinone anion and accompanied polypeptide rearrangements mediated by different redox steps.
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6
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Cryo-EM structures of Na +-pumping NADH-ubiquinone oxidoreductase from Vibrio cholerae. Nat Commun 2022; 13:4082. [PMID: 35882843 PMCID: PMC9325719 DOI: 10.1038/s41467-022-31718-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/29/2022] [Indexed: 11/08/2022] Open
Abstract
The Na+-pumping NADH-ubiquinone oxidoreductase (Na+-NQR) couples electron transfer from NADH to ubiquinone with Na+-pumping, generating an electrochemical Na+ gradient that is essential for energy-consuming reactions in bacteria. Since Na+-NQR is exclusively found in prokaryotes, it is a promising target for highly selective antibiotics. However, the molecular mechanism of inhibition is not well-understood for lack of the atomic structural information about an inhibitor-bound state. Here we present cryo-electron microscopy structures of Na+-NQR from Vibrio cholerae with or without a bound inhibitor at 2.5- to 3.1-Å resolution. The structures reveal the arrangement of all six redox cofactors including a herein identified 2Fe-2S cluster located between the NqrD and NqrE subunits. A large part of the hydrophilic NqrF is barely visible in the density map, suggesting a high degree of flexibility. This flexibility may be responsible to reducing the long distance between the 2Fe-2S centers in NqrF and NqrD/E. Two different types of specific inhibitors bind to the N-terminal region of NqrB, which is disordered in the absence of inhibitors. The present study provides a foundation for understanding the function of Na+-NQR and the binding manner of specific inhibitors.
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7
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Tuz K, Yuan M, Hu Y, Do TTT, Willow SY, DePaolo-Boisvert JA, Fuller JR, Minh DDL, Juárez O. Identification of the riboflavin-cofactor binding site in the Vibrio cholerae ion-pumping NQR complex: A novel structural motif in redox enzymes. J Biol Chem 2022; 298:102182. [PMID: 35752362 PMCID: PMC9293633 DOI: 10.1016/j.jbc.2022.102182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/16/2022] [Accepted: 06/18/2022] [Indexed: 11/18/2022] Open
Abstract
The ion-pumping NQR complex is an essential respiratory enzyme in the physiology of many pathogenic bacteria. This enzyme transfers electrons from NADH to ubiquinone through several cofactors, including riboflavin (vitamin B2). NQR is the only enzyme reported that is able to use riboflavin as a cofactor. Moreover, the riboflavin molecule is found as a stable neutral semiquinone radical. The otherwise highly reactive unpaired electron is stabilized via an unknown mechanism. Crystallographic data suggested that riboflavin might be found in a superficially located site in the interface of NQR subunits B and E. However, this location is highly problematic, as the site does not have the expected physiochemical properties. In this work, we have located the riboflavin-binding site in an amphipathic pocket in subunit B, previously proposed to be the entry site of sodium. Here, we show that this site contains absolutely conserved residues, including N200, N203, and D346. Mutations of these residues decrease enzymatic activity and specifically block the ability of NQR to bind riboflavin. Docking analysis and molecular dynamics simulations indicate that these residues participate directly in riboflavin binding, establishing hydrogen bonds that stabilize the cofactor in the site. We conclude that riboflavin is likely bound in the proposed pocket, which is consistent with enzymatic characterizations, thermodynamic studies, and distance between cofactors.
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Affiliation(s)
- Karina Tuz
- Department of Biological Sciences, Illinois Institute of Technology, Chicago IL
| | - Ming Yuan
- Department of Biological Sciences, Illinois Institute of Technology, Chicago IL
| | - Yuyao Hu
- Department of Biological Sciences, Illinois Institute of Technology, Chicago IL
| | - Tien T T Do
- Department of Chemistry, Illinois Institute of Technology, Chicago IL
| | | | | | - James R Fuller
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL
| | - David D L Minh
- Department of Chemistry, Illinois Institute of Technology, Chicago IL
| | - Oscar Juárez
- Department of Biological Sciences, Illinois Institute of Technology, Chicago IL.
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8
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Ishikawa M, Masuya T, Kuroda S, Uno S, Butler NL, Foreman S, Murai M, Barquera B, Miyoshi H. The side chain of ubiquinone plays a critical role in Na + translocation by the NADH-ubiquinone oxidoreductase (Na +-NQR) from Vibrio cholerae. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148547. [PMID: 35337841 DOI: 10.1016/j.bbabio.2022.148547] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/18/2022] [Accepted: 03/17/2022] [Indexed: 11/19/2022]
Abstract
The Na+-pumping NADH-ubiquinone (UQ) oxidoreductase (Na+-NQR) is an essential bacterial respiratory enzyme that generates a Na+ gradient across the cell membrane. However, the mechanism that couples the redox reactions to Na+ translocation remains unknown. To address this, we examined the relation between reduction of UQ and Na+ translocation using a series of synthetic UQs with Vibrio cholerae Na+-NQR reconstituted into liposomes. UQ0 that has no side chain and UQCH3 and UQC2H5, which have methyl and ethyl side chains, respectively, were catalytically reduced by Na+-NQR, but their reduction generated no membrane potential, indicating that the overall electron transfer and Na+ translocation are not coupled. While these UQs were partly reduced by electron leak from the cofactor(s) located upstream of riboflavin, this complete loss of Na+ translocation cannot be explained by the electron leak. Lengthening the UQ side chain to n-propyl (C3H7) or longer significantly restored Na+ translocation. It has been considered that Na+ translocation is completed when riboflavin, a terminal redox cofactor residing within the membrane, is reduced. In this view, the role of UQ is simply to accept electrons from the reduced riboflavin to regenerate the stable neutral riboflavin radical and reset the catalytic cycle. However, the present study revealed that the final UQ reduction via reduced riboflavin makes an important contribution to Na+ translocation through a critical role of its side chain. Based on the results, we discuss the critical role of the UQ side chain in Na+ translocation.
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Affiliation(s)
- Moe Ishikawa
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Takahiro Masuya
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Seina Kuroda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Shinpei Uno
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Nicole L Butler
- Department of Biological Science, Rensselaer Polytechnic Institute, Troy, NY 12180, United States
| | - Sara Foreman
- Department of Biological Science, Rensselaer Polytechnic Institute, Troy, NY 12180, United States
| | - Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Blanca Barquera
- Department of Biological Science, Rensselaer Polytechnic Institute, Troy, NY 12180, United States; Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, United States
| | - Hideto Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
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9
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Kong Z, Zhou Y, Fu Z, Zhang Y, Yan R. Mechanism of stable power generation and nitrogen removal in the ANAMMOX-MFC treating low C/N wastewater. CHEMOSPHERE 2022; 296:133937. [PMID: 35167835 DOI: 10.1016/j.chemosphere.2022.133937] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 01/14/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
This study investigated the mechanism of enhanced power generation and nitrogen removal in an ANAMMOX-MFC reactor through subsequent acetate addition. Data showed that nearly 99% total nitrogen removal (≤1 mg L-1) and 1.41 W m-3 power generation were achieved synchronously under low COD/N (∼1.5) after the subsequent addition of acetate (100 mgCOD·L-1). The columbic efficiency of the system has increased by 15 times (from 0.64% to 9.48%) after adding acetate. Batch tests showed that the denitrification and ANAMMOX progress occurred synchronously before acetate addition the nitrogen removal rate was accelerated. A distinct shift of bacterial community driven by acetate addition was discovered. The high throughput sequencing analysis indicated acetate addition stimulated the enrichment of denitrifiers, such as Aquimonas, Bradyrhizobium, Thauera, and the potential exoelectrogens changing from Comamonas to Pseudomonas. Functional genes forecasts based on KEGG database and COG database showed that the expressions of TCA functional genes were highly promoted in ANAMMOX-MFC, which demonstrated the enhanced electron transfer pathway driven by acetate addition under low COD/N ratio.
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Affiliation(s)
- Zhiyuan Kong
- Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010031, China; Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Yongheng Zhou
- Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010031, China
| | - Zhimin Fu
- Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010031, China.
| | - Yuancan Zhang
- Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010031, China
| | - Rong Yan
- Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010031, China
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10
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Willow SY, Yuan M, Juárez O, Minh DDL. Electrostatics and water occlusion regulate covalently-bound flavin mononucleotide cofactors of Vibrio cholerae respiratory complex NQR. Proteins 2021; 89:1376-1385. [PMID: 34091964 DOI: 10.1002/prot.26158] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/20/2021] [Accepted: 06/01/2021] [Indexed: 12/20/2022]
Abstract
Proteins like NADH:ubiquinone oxidoreductase (NQR), an essential enzyme and ion pump in the physiology of several pathogenic bacteria, tightly regulate the redox properties of their cofactors. Although flavin mononucleotide (FMN) is fully reduced in aqueous solution, FMN in subunits B and C of NQR exclusively undergo one-electron transitions during its catalytic cycle. Here, we perform ab initio calculations and molecular dynamics simulations to elucidate the mechanisms that regulate the redox state of FMN in NQR. QM/MM calculations show that binding site electrostatics disfavor anionic forms of FMNH2 , but permit a neutral form of the fully reduced flavin. The potential energy surface is unaffected by covalent bonding between FMN and threonine. Molecular dynamics simulations show that the FMN binding sites are inaccessible by water, suggesting that further reductions of the cofactors are limited or prohibited by the availability of water and other proton donors. These findings provide a deeper understanding of the mechanisms used by NQR to regulate electron transfer through the cofactors and perform its physiologic role. They also provide the first, to our knowledge, evidence of the simple concept that proteins regulate flavin redox states via water occlusion.
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Affiliation(s)
- Soohaeng Yoo Willow
- Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois, USA
| | - Ming Yuan
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, USA
| | - Oscar Juárez
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, USA
| | - David D L Minh
- Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois, USA
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11
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Specific chemical modification explores dynamic structure of the NqrB subunit in Na +-pumping NADH-ubiquinone oxidoreductase from Vibrio cholerae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148432. [PMID: 33932367 DOI: 10.1016/j.bbabio.2021.148432] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/20/2021] [Indexed: 12/28/2022]
Abstract
The Na+-pumping NADH-ubiquinone oxidoreductase (Na+-NQR) is a main ion transporter in many pathogenic bacteria. We previously proposed that N-terminal stretch of the NqrB subunit plays an important role in regulating the ubiquinone reaction at the adjacent NqrA subunit in Vibrio cholerae Na+-NQR. However, since approximately three quarters of the stretch (NqrB-Met1-Pro37) was not modeled in an earlier crystallographic study, its structure and function remain unknown. If we can develop a method that enables pinpoint modification of this stretch by functional chemicals (such as spin probes), it could lead to new ways to investigate the unsettled issues. As the first step to this end, we undertook to specifically attach an alkyne group to a lysine located in the stretch via protein-ligand affinity-driven substitution using synthetic ligands NAS-K1 and NAS-K2. The alkyne, once attached, can serve as an "anchor" for connecting functional chemicals via convenient click chemistry. After a short incubation of isolated Na+-NQR with these ligands, alkyne was predominantly incorporated into NqrB. Proteomic analyses in combination with mutagenesis of predicted target lysines revealed that alkyne attaches to NqrB-Lys22 located at the nonmodeled region of the stretch. This study not only achieved the specific modification initially aimed for but also provided valuable information about positioning of the nonmodeled region. For example, the fact that hydrophobic NAS-Ks come into contact with NqrB-Lys22 suggests that the nonmodeled region may orient toward the membrane phase rather than protruding into cytoplasmic medium. This conformation may be essential for regulating the ubiquinone reaction in the adjacent NqrA.
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12
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Furusawa G, Diyana T, Lau NS. Metabolic strategies of dormancy of a marine bacterium Microbulbifer aggregans CCB-MM1: Its alternative electron transfer chain and sulfate-reducing pathway. Genomics 2021; 114:443-455. [PMID: 33689784 DOI: 10.1016/j.ygeno.2021.02.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 01/26/2021] [Accepted: 02/28/2021] [Indexed: 12/26/2022]
Abstract
Bacterial dormancy plays a crucial role in maintaining the functioning and diversity of microbial communities in natural environments. However, the metabolic regulations of the dormancy of bacteria in natural habitats, especially marine habitats, have remained largely unknown. A marine bacterium, Microbulbifer aggregans CCB-MM1 exhibits rod-to-coccus cell shape change during the dormant state. Therefore, to clarify the metabolic regulation of the dormancy, differential gene expression analysis based on RNA-Seq was performed between rod- (vegetative), intermediate, and coccus-shaped cells (dormancy). The RNA-Seq data revealed that one of two distinct electron transfer chains was upregulated in the dormancy. Dissimilatory sulfite reductase and soluble hydrogenase were also highly upregulated in the dormancy. In addition, induction of the dormancy of MM1 in the absence of MgSO4 was slower than that in the presence of MgSO4. These results indicate that the sulfate-reducing pathway plays an important role in entering the dormancy of MM1.
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Affiliation(s)
- Go Furusawa
- Centre for Chemical Biology, Universiti Sains Malaysia, 10 Persiaran Bukit Jambul, 11900 Bayan Lepas, Penang, Malaysia.
| | - Tarmizi Diyana
- Centre for Chemical Biology, Universiti Sains Malaysia, 10 Persiaran Bukit Jambul, 11900 Bayan Lepas, Penang, Malaysia
| | - Nyok-Sean Lau
- Centre for Chemical Biology, Universiti Sains Malaysia, 10 Persiaran Bukit Jambul, 11900 Bayan Lepas, Penang, Malaysia
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13
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Masuya T, Sano Y, Tanaka H, Butler NL, Ito T, Tosaki T, Morgan JE, Murai M, Barquera B, Miyoshi H. Inhibitors of a Na +-pumping NADH-ubiquinone oxidoreductase play multiple roles to block enzyme function. J Biol Chem 2020; 295:12739-12754. [PMID: 32690607 DOI: 10.1074/jbc.ra120.014229] [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] [Received: 05/05/2020] [Revised: 07/18/2020] [Indexed: 11/06/2022] Open
Abstract
The Na+-pumping NADH-ubiquinone (UQ) oxidoreductase (Na+-NQR) is present in the respiratory chain of many pathogenic bacteria and is thought to be a promising antibiotic target. Whereas many details of Na+-NQR structure and function are known, the mechanisms of action of potent inhibitors is not well-understood; elucidating the mechanisms would not only advance drug design strategies but might also provide insights on a terminal electron transfer from riboflavin to UQ. To this end, we performed photoaffinity labeling experiments using photoreactive derivatives of two known inhibitors, aurachin and korormicin, on isolated Vibrio cholerae Na+-NQR. The inhibitors labeled the cytoplasmic surface domain of the NqrB subunit including a protruding N-terminal stretch, which may be critical to regulate the UQ reaction in the adjacent NqrA subunit. The labeling was blocked by short-chain UQs such as ubiquinone-2. The photolabile group (2-aryl-5-carboxytetrazole (ACT)) of these inhibitors reacts with nucleophilic amino acids, so we tested mutations of nucleophilic residues in the labeled region of NqrB, such as Asp49 and Asp52 (to Ala), and observed moderate decreases in labeling yields, suggesting that these residues are involved in the interaction with ACT. We conclude that the inhibitors interfere with the UQ reaction in two ways: the first is blocking structural rearrangements at the cytoplasmic interface between NqrA and NqrB, and the second is the direct obstruction of UQ binding at this interfacial area. Unusual competitive behavior between the photoreactive inhibitors and various competitors corroborates our previous proposition that there may be two inhibitor binding sites in Na+-NQR.
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Affiliation(s)
- Takahiro Masuya
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yuki Sano
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hinako Tanaka
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | | | | | - Tatsuhiko Tosaki
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Joel E Morgan
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Blanca Barquera
- Department of Biological Science and.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Hideto Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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14
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Zolti A, Green SJ, Sela N, Hadar Y, Minz D. The microbiome as a biosensor: functional profiles elucidate hidden stress in hosts. MICROBIOME 2020; 8:71. [PMID: 32438915 PMCID: PMC7243336 DOI: 10.1186/s40168-020-00850-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 04/28/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND Microbial communities are highly responsive to environmental cues, and both their structure and activity can be altered in response to changing conditions. We hypothesized that host-associated microbial communities, particularly those colonizing host surfaces, can serve as in situ sensors to reveal environmental conditions experienced by both microorganisms and the host. For a proof-of-concept, we studied a model plant-soil system and employed a non-deterministic gene-centric approach. A holistic analysis was performed using plants of two species and irrigation with water of low quality to induce host stress. Our analyses examined the genetic potential (DNA) and gene expression patterns (RNA) of plant-associated microbial communities, as well as transcriptional profiling of host plants. RESULTS Transcriptional analysis of plants irrigated with treated wastewater revealed significant enrichment of general stress-associated root transcripts relative to plants irrigated with fresh water. Metagenomic analysis of root-associated microbial communities in treated wastewater-irrigated plants, however, revealed enrichment of more specific stress-associated genes relating to high levels of salt, high pH and lower levels of oxygen. Meta-analysis of these differentially abundant genes obtained from other metagenome studies, provided evidence of the link between environmental factors such as pH and oxygen and these genes. Analysis of microbial transcriptional response demonstrated that enriched gene content was actively expressed, which implies contemporary response to elevated levels of pH and salt. CONCLUSIONS We demonstrate here that microbial profiling can elucidate stress signals that cannot be observed even through interrogation of host transcriptome, leading to an alternate mechanism for evaluating in situ conditions experienced by host organisms. This study is a proof-of-concept for the use of microbial communities as microsensors, with great potential for interrogation of a wide range of host systems. Video Abstract.
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Affiliation(s)
- Avihai Zolti
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100 Rehovot, Israel
- Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization–Volcani Center, 7528809 Rishon Lezion, Israel
| | - Stefan J. Green
- Sequencing Core, Research Resources Center, University of Illinois at Chicago, Chicago, IL USA
| | - Noa Sela
- Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization–Volcani Center, 7528809 Rishon Lezion, Israel
| | - Yitzhak Hadar
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100 Rehovot, Israel
| | - Dror Minz
- Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization–Volcani Center, 7528809 Rishon Lezion, Israel
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15
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The aerobic respiratory chain of Pseudomonas aeruginosa cultured in artificial urine media: Role of NQR and terminal oxidases. PLoS One 2020; 15:e0231965. [PMID: 32324772 PMCID: PMC7179901 DOI: 10.1371/journal.pone.0231965] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative γ-proteobacterium that forms part of the normal human microbiota and it is also an opportunistic pathogen, responsible for 30% of all nosocomial urinary tract infections. P. aeruginosa carries a highly branched respiratory chain that allows the colonization of many environments, such as the urinary tract, catheters and other medical devices. P. aeruginosa respiratory chain contains three different NADH dehydrogenases (complex I, NQR and NDH-2), whose physiologic roles have not been elucidated, and up to five terminal oxidases: three cytochrome c oxidases (COx), a cytochrome bo3 oxidase (CYO) and a cyanide-insensitive cytochrome bd-like oxidase (CIO). In this work, we studied the composition of the respiratory chain of P. aeruginosa cells cultured in Luria Broth (LB) and modified artificial urine media (mAUM), to understand the metabolic adaptations of this microorganism to the growth in urine. Our results show that the COx oxidases play major roles in mAUM, while P. aeruginosa relies on CYO when growing in LB medium. Moreover, our data demonstrate that the proton-pumping NQR complex is the main NADH dehydrogenase in both LB and mAUM. This enzyme is resistant to HQNO, an inhibitory molecule produced by P. aeruginosa, and may provide an advantage against the natural antibacterial agents produced by this organism. This work offers a clear picture of the composition of this pathogen’s aerobic respiratory chain and the main roles that NQR and terminal oxidases play in urine, which is essential to understand its physiology and could be used to develop new antibiotics against this notorious multidrug-resistant microorganism.
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16
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Raba D, Yuan M, Fang X, Menzer WM, Xie B, Liang P, Tuz K, Minh DDL, Juárez O. Role of Subunit D in Ubiquinone-Binding Site of Vibrio cholerae NQR: Pocket Flexibility and Inhibitor Resistance. ACS OMEGA 2019; 4:19324-19331. [PMID: 31763556 PMCID: PMC6868883 DOI: 10.1021/acsomega.9b02707] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/22/2019] [Indexed: 06/10/2023]
Abstract
The ion-pumping NADH: ubiquinone dehydrogenase (NQR) is a vital component of the respiratory chain of numerous species of marine and pathogenic bacteria, including Vibrio cholerae. This respiratory enzyme couples the transfer of electrons from NADH to ubiquinone (UQ) to the pumping of ions across the plasma membrane, producing a gradient that sustains multiple homeostatic processes. The binding site of UQ within the enzyme is an important functional and structural motif that could be used to design drugs against pathogenic bacteria. Our group recently located the UQ site in the interface between subunits B and D and identified the residues within subunit B that are important for UQ binding. In this study, we carried out alanine scanning mutagenesis of amino acid residues located in subunit D of V. cholerae NQR to understand their role in UQ binding and enzymatic catalysis. Moreover, molecular docking calculations were performed to characterize the structure of the site at the atomic level. The results show that mutations in these positions, in particular, in residues P185, L190, and F193, decrease the turnover rate and increase the Km for UQ. These mutants also showed an increase in the resistance against the inhibitor HQNO. The data indicate that residues in subunit D fulfill important structural roles, restricting and orienting UQ in a catalytically favorable position. In addition, mutations of these residues open the site and allow the simultaneous binding of substrate and inhibitors, producing partial inhibition, which appears to be a strategy used by Pseudomonas aeruginosa to avoid autopoisoning.
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Affiliation(s)
- Daniel
A. Raba
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Ming Yuan
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Xuan Fang
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - William M. Menzer
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Bing Xie
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Pingdong Liang
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Karina Tuz
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - David D. L. Minh
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Oscar Juárez
- Department
of Biological Sciences and Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
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17
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Liu Y, Yin H, Wei K, Peng H, Lu G, Dang Z. Biodegradation of tricresyl phosphate isomers by Brevibacillus brevis: Degradation pathway and metabolic mechanism. CHEMOSPHERE 2019; 232:195-203. [PMID: 31154180 DOI: 10.1016/j.chemosphere.2019.05.188] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 05/12/2019] [Accepted: 05/22/2019] [Indexed: 06/09/2023]
Abstract
Tricresyl phosphates (TCPs), a typical sort of organophosphate flame retardants, has received extensive concerns due to its potential adverse effects. However, limited information is available on the efficient and safe removal methods of TCPs. In this regard, TCPs were tentatively biodegraded with Brevibacillus brevis. A probable degradation pathway was further proposed with the cellular reactions discussed in detail. Experiments showed that B. brevis at 2 g L-1 could degrade 1 mg L-1 tri-m-cresyl phosphate, tri-p-cresyl phosphate, and tri-o-cresyl phosphate by 82.91%, 93.91%, and 53.92%, respectively, within five days. In the process of biodegradation, B. brevis metabolism caused the release of Na+ and Cl- as well as the absorption of some nutrient ions including K+, PO43-, Mg2+, and SO42-; the presence of oxalic acid, citric acid, acetic acid, and malonic acid was also detected. Similar metabolic pathways were found among different TCPs isomers, but tri-o-cresyl phosphate induced more reactive oxygen species than the other two did. This work develops novel insights into the potential mechanisms of TCPs biodegradation by microorganisms.
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Affiliation(s)
- Ying Liu
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, PR China
| | - Hua Yin
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, PR China.
| | - Kun Wei
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, PR China
| | - Hui Peng
- Department of Chemistry, Jinan University, Guangzhou, 510632, Guangdong, PR China
| | - Guining Lu
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, PR China
| | - Zhi Dang
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, School of Environment and Energy, South China University of Technology, Guangzhou, 510006, Guangdong, PR China
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18
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Type IV Pili as a Therapeutic Target. Trends Microbiol 2019; 27:658-661. [DOI: 10.1016/j.tim.2019.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 01/02/2023]
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19
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Elabed H, González-Tortuero E, Ibacache-Quiroga C, Bakhrouf A, Johnston P, Gaddour K, Blázquez J, Rodríguez-Rojas A. Seawater salt-trapped Pseudomonas aeruginosa survives for years and gets primed for salinity tolerance. BMC Microbiol 2019; 19:142. [PMID: 31234794 PMCID: PMC6591848 DOI: 10.1186/s12866-019-1499-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 05/31/2019] [Indexed: 01/08/2023] Open
Abstract
Background In nature, microorganisms have to adapt to long-term stressful conditions often with growth limitations. However, little is known about the evolution of the adaptability of new bacteria to such environments. Pseudomonas aeruginosa, an opportunistic pathogen, after natural evaporation of seawater, was shown to be trapped in laboratory-grown halite crystals and to remain viable after entrapment for years. However, how this bacterium persists and survives in such hypersaline conditions is not understood. Results In this study, we aimed to understand the basis of survival, and to characterise the physiological changes required to develop salt tolerance using P. aeruginosa as a model. Several clones of P. aeruginosa were rescued after 14 years in naturally evaporated marine salt crystals. Incubation of samples in nutrient-rich broth allowed re-growth and subsequent plating yielded observable colonies. Whole genome sequencing of the P. aeruginosa isolates confirmed the recovery of the original strain. The re-grown strains, however, showed a new phenotype consisting of an enhanced growth in growing salt concentration compared to the ancestor strain. The intracellular accumulation of K+ was elicited by high concentration of Na+ in the external medium to maintain the homeostasis. Whole transcriptomic analysis by microarray indicated that 78 genes had differential expression between the parental strain and its derivative clones. Sixty-one transcripts were up-regulated, while 17 were down-regulated. Based on a collection of single-gene knockout mutants and gene ontology analysis, we suggest that the adaptive response in P. aeruginosa to hyper-salinity relies on multiple gene product interactions. Conclusions The individual gene contributions build up the observed phenotype, but do not ease the identification of salinity-related metabolic pathways. The long-term inclusion of P. aeruginosa in salt crystals primes the bacteria, mediating a readjustment of the bacterial physiology to growth in higher salt concentrations. Our findings provide a starting point to understand how P. aeruginosa, a relevant environmental and pathogenic bacterium, survives to long-term salt stress. Electronic supplementary material The online version of this article (10.1186/s12866-019-1499-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hamouda Elabed
- Laboratory of Contagious Diseases and Biologically Active Substances LR99-ES27 Faculty of Pharmacy of Monastir, University of Monastir, Monastir, Tunisia.,Department of Microbial Biotechnology, Spanish National Center for Biotechnology (CNB), Madrid, Spain
| | - Enrique González-Tortuero
- Department of Veterinary and Animal Sciences, Center for non-coding RNA in Technology and Health, University of Copenhagen, Copenhagen, Denmark
| | - Claudia Ibacache-Quiroga
- Department of Microbial Biotechnology, Spanish National Center for Biotechnology (CNB), Madrid, Spain.,Centro de Micro-Bioinnovación, Escuela de Nutrición y Dietética, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso, Chile
| | - Amina Bakhrouf
- Laboratory of Analysis, Treatment and Valorization of Environmental Polluants and products, Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
| | - Paul Johnston
- Institute of Biology, FreieUniversität Berlin, Berlin, Germany
| | - Kamel Gaddour
- Laboratory of Analysis, Treatment and Valorization of Environmental Polluants and products, Faculty of Pharmacy, University of Monastir, Monastir, Tunisia
| | - Jesús Blázquez
- Department of Microbial Biotechnology, Spanish National Center for Biotechnology (CNB), Madrid, Spain
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20
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Coureuil M, Jamet A, Bille E, Lécuyer H, Bourdoulous S, Nassif X. Molecular interactions between Neisseria meningitidis and its human host. Cell Microbiol 2019; 21:e13063. [PMID: 31167044 PMCID: PMC6899865 DOI: 10.1111/cmi.13063] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/21/2019] [Accepted: 05/30/2019] [Indexed: 02/06/2023]
Abstract
Neisseria meningitidis is a Gram‐negative bacterium that asymptomatically colonises the nasopharynx of humans. For an unknown reason, N. meningitidis can cross the nasopharyngeal barrier and invade the bloodstream where it becomes one of the most harmful extracellular bacterial pathogen. This infectious cycle involves the colonisation of two different environments. (a) In the nasopharynx, N. meningitidis grow on the top of mucus‐producing epithelial cells surrounded by a complex microbiota. To survive and grow in this challenging environment, the meningococcus expresses specific virulence factors such as polymorphic toxins and MDAΦ. (b) Meningococci have the ability to survive in the extra cellular fluids including blood and cerebrospinal fluid. The interaction of N. meningitidis with human endothelial cells leads to the formation of typical microcolonies that extend overtime and promote vascular injury, disseminated intravascular coagulation, and acute inflammation. In this review, we will focus on the interplay between N. meningitidis and these two different niches at the cellular and molecular level and discuss the use of inhibitors of piliation as a potent therapeutic approach.
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Affiliation(s)
- Mathieu Coureuil
- Inserm, Institut Necker Enfants Malades, U1151, Paris, France.,Université de Paris, UMR_S 1151, Paris, France.,CNRS, UMR 8253, Paris, France
| | - Anne Jamet
- Inserm, Institut Necker Enfants Malades, U1151, Paris, France.,Université de Paris, UMR_S 1151, Paris, France.,CNRS, UMR 8253, Paris, France.,Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades, Paris, France
| | - Emmanuelle Bille
- Inserm, Institut Necker Enfants Malades, U1151, Paris, France.,Université de Paris, UMR_S 1151, Paris, France.,CNRS, UMR 8253, Paris, France.,Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades, Paris, France
| | - Hervé Lécuyer
- Inserm, Institut Necker Enfants Malades, U1151, Paris, France.,Université de Paris, UMR_S 1151, Paris, France.,CNRS, UMR 8253, Paris, France.,Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades, Paris, France
| | - Sandrine Bourdoulous
- Université de Paris, UMR_S 1151, Paris, France.,Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France
| | - Xavier Nassif
- Inserm, Institut Necker Enfants Malades, U1151, Paris, France.,Université de Paris, UMR_S 1151, Paris, France.,CNRS, UMR 8253, Paris, France.,Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades, Paris, France
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21
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Moradali MF, Ghods S, Angelini TE, Davey ME. Amino acids as wetting agents: surface translocation by Porphyromonas gingivalis. THE ISME JOURNAL 2019; 13:1560-1574. [PMID: 30783212 PMCID: PMC6775972 DOI: 10.1038/s41396-019-0360-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/11/2019] [Accepted: 01/17/2019] [Indexed: 02/06/2023]
Abstract
Our understanding of how oral microbiota adapt in response to changes in their surroundings remains limited. This is particularly true of the slow-growing anaerobes that persist below the gum line. Here, we report that the oral anaerobe Porphyromonas gingivalis strain 381 can surface translocate when sandwiched between two surfaces. We show that during movement, this bacterium alters its metabolism, specifically side products of arginine utilization including citrulline and ornithine accumulated in the translocating cells; while arginine, N-acetyl-arginine, and the polyamine putrescine, which is produced from arginine were consumed. In addition, our results indicate that movement requires modification of the surrounding environment via proteolysis, cell dispersion, cell-on-cell rolling, and sub-diffusive cell-driven motility. We also show that production of fimbriae and fimbriae-associated proteins; as well as the regulation of contact-dependent growth inhibition genes, which are known to be involved in self-nonself discrimination, and the type IX secretion system are central to surface translocation. These studies provide a first glimpse into P. gingivalis motility and its relationship to ecological variables.
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Affiliation(s)
- M Fata Moradali
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA
| | - Shirin Ghods
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA
| | - Thomas E Angelini
- Department of Mechanical & Aerospace Engineering, University of Florida, Gainesville, FL, 32610, USA
| | - Mary Ellen Davey
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, 32610, USA.
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22
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Occurrence and Function of the Na +-Translocating NADH:Quinone Oxidoreductase in Prevotella spp. Microorganisms 2019; 7:microorganisms7050117. [PMID: 31035603 PMCID: PMC6560451 DOI: 10.3390/microorganisms7050117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/08/2019] [Accepted: 04/25/2019] [Indexed: 12/18/2022] Open
Abstract
Strictly anaerobic Prevotella spp. are characterized by their vast metabolic potential. As members of the Prevotellaceae family, they represent the most abundant organisms in the rumen and are typically found in monogastrics such as pigs and humans. Within their largely anoxic habitats, these bacteria are considered to rely primarily on fermentation for energy conservation. A recent study of the rumen microbiome identified multiple subunits of the Na+-translocating NADH:quinone oxidoreductase (NQR) belonging to different Prevotella spp. Commonly, the NQR is associated with biochemical energy generation by respiration. The existence of this Na+ pump in Prevotella spp. may indicate an important role for electrochemical Na+ gradients in their anaerobic metabolism. However, detailed information about the potential activity of the NQR in Prevotella spp. is not available. Here, the presence of a functioning NQR in the strictly anaerobic model organism P. bryantii B14 was verified by conducting mass spectrometric, biochemical, and kinetic experiments. Our findings propose that P. bryantii B14 and other Prevotella spp. retrieved from the rumen operate a respiratory NQR together with a fumarate reductase which suggests that these ruminal bacteria utilize a sodium motive force generated during respiratory NADH:fumarate oxidoreduction.
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23
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Denis K, Le Bris M, Le Guennec L, Barnier JP, Faure C, Gouge A, Bouzinba-Ségard H, Jamet A, Euphrasie D, Durel B, Barois N, Pelissier P, Morand PC, Coureuil M, Lafont F, Join-Lambert O, Nassif X, Bourdoulous S. Targeting Type IV pili as an antivirulence strategy against invasive meningococcal disease. Nat Microbiol 2019; 4:972-984. [PMID: 30911127 DOI: 10.1038/s41564-019-0395-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 01/30/2019] [Indexed: 11/09/2022]
Abstract
Bacterial virulence factors are attractive targets for the development of therapeutics. Type IV pili, which are associated with a remarkable array of properties including motility, the interaction between bacteria and attachment to biotic and abiotic surfaces, represent particularly appealing virulence factor targets. Type IV pili are present in numerous bacterial species and are critical for their pathogenesis. In this study, we report that trifluoperazine and related phenothiazines block functions associated with Type IV pili in different bacterial pathogens, by affecting piliation within minutes. Using Neisseria meningitidis as a paradigm of Gram-negative bacterial pathogens that require Type IV pili for pathogenesis, we show that piliation is sensitive to altered activity of the Na+ pumping NADH-ubiquinone oxidoreductase (Na+-NQR) complex and that these compounds probably altered the establishment of the sodium gradient. In vivo, these compounds exert a strong protective effect. They reduce meningococcal colonization of the human vessels and prevent subsequent vascular dysfunctions, intravascular coagulation and overwhelming inflammation, the hallmarks of invasive meningococcal infections. Finally, they reduce lethality. This work provides a proof of concept that compounds with activity against bacterial Type IV pili could beneficially participate in the treatment of infections caused by Type IV pilus-expressing bacteria.
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Affiliation(s)
- Kevin Denis
- U1016, Institut Cochin, Inserm, Paris, France.,UMR8104, CNRS, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marion Le Bris
- U1016, Institut Cochin, Inserm, Paris, France.,UMR8104, CNRS, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Loic Le Guennec
- U1016, Institut Cochin, Inserm, Paris, France.,UMR8104, CNRS, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jean-Philippe Barnier
- U1151, Institut Necker Enfants Malades, Inserm, Paris, France.,UMR 8253, CNRS, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Hôpital Necker Enfants Malades, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Camille Faure
- U1016, Institut Cochin, Inserm, Paris, France.,UMR8104, CNRS, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Anne Gouge
- U1016, Institut Cochin, Inserm, Paris, France.,UMR8104, CNRS, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Haniaa Bouzinba-Ségard
- U1016, Institut Cochin, Inserm, Paris, France.,UMR8104, CNRS, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Anne Jamet
- U1151, Institut Necker Enfants Malades, Inserm, Paris, France.,UMR 8253, CNRS, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Hôpital Necker Enfants Malades, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Daniel Euphrasie
- U1151, Institut Necker Enfants Malades, Inserm, Paris, France.,UMR 8253, CNRS, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Hôpital Necker Enfants Malades, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Beatrice Durel
- U1016, Institut Cochin, Inserm, Paris, France.,UMR8104, CNRS, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Nicolas Barois
- Cellular Microbiology and Physics of Infection Group, Centre for Infection and Immunity of Lille, Institut Pasteur de Lille, Lille, France.,UMR 8204, CNRS, Lille, France.,U1019, Inserm, Lille, France.,Université de Lille, Lille, France
| | - Philippe Pelissier
- Service de Chirurgie Reconstructrice et Plastique, Fondation Hôpital Saint Joseph, Paris, France
| | - Philippe C Morand
- U1016, Institut Cochin, Inserm, Paris, France.,UMR8104, CNRS, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Mathieu Coureuil
- U1151, Institut Necker Enfants Malades, Inserm, Paris, France.,UMR 8253, CNRS, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Frank Lafont
- Cellular Microbiology and Physics of Infection Group, Centre for Infection and Immunity of Lille, Institut Pasteur de Lille, Lille, France.,UMR 8204, CNRS, Lille, France.,U1019, Inserm, Lille, France.,Université de Lille, Lille, France
| | - Olivier Join-Lambert
- U1151, Institut Necker Enfants Malades, Inserm, Paris, France.,UMR 8253, CNRS, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Hôpital Necker Enfants Malades, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Xavier Nassif
- U1151, Institut Necker Enfants Malades, Inserm, Paris, France.,UMR 8253, CNRS, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Hôpital Necker Enfants Malades, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Sandrine Bourdoulous
- U1016, Institut Cochin, Inserm, Paris, France. .,UMR8104, CNRS, Paris, France. .,Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
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24
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Raba DA, Rosas-Lemus M, Menzer WM, Li C, Fang X, Liang P, Tuz K, Minh DDL, Juárez O. Characterization of the Pseudomonas aeruginosa NQR complex, a bacterial proton pump with roles in autopoisoning resistance. J Biol Chem 2018; 293:15664-15677. [PMID: 30135204 DOI: 10.1074/jbc.ra118.003194] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 08/13/2018] [Indexed: 12/22/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative bacterium responsible for a large number of nosocomial infections. The P. aeruginosa respiratory chain contains the ion-pumping NADH:ubiquinone oxidoreductase (NQR). This enzyme couples the transfer of electrons from NADH to ubiquinone to the pumping of sodium ions across the cell membrane, generating a gradient that drives essential cellular processes in many bacteria. In this study, we characterized P. aeruginosa NQR (Pa-NQR) to elucidate its physiologic function. Our analyses reveal that Pa-NQR, in contrast with NQR homologues from other bacterial species, is not a sodium pump, but rather a completely new form of proton pump. Homology modeling and molecular dynamics simulations suggest that cation selectivity could be determined by the exit ion channels. We also show that Pa-NQR is resistant to the inhibitor 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO). HQNO is a quinolone secreted by P. aeruginosa during infection that acts as a quorum sensing agent and also has bactericidal properties against other bacteria. Using comparative analysis and computational modeling of the ubiquinone-binding site, we identified the specific residues that confer resistance toward this inhibitor. In summary, our findings indicate that Pa-NQR is a proton pump rather than a sodium pump and is highly resistant against the P. aeruginosa-produced compound HQNO, suggesting an important role in the adaptation against autotoxicity. These results provide a deep understanding of the metabolic role of NQR in P. aeruginosa and provide insight into the structural factors that determine the functional specialization in this family of respiratory complexes.
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Affiliation(s)
| | | | - William M Menzer
- From the Departments of Biological Sciences and.,Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Chen Li
- Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Xuan Fang
- From the Departments of Biological Sciences and
| | | | - Karina Tuz
- From the Departments of Biological Sciences and
| | - David D L Minh
- Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616
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25
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Manzoor S, Schnürer A, Bongcam-Rudloff E, Müller B. Genome-Guided Analysis of Clostridium ultunense and Comparative Genomics Reveal Different Strategies for Acetate Oxidation and Energy Conservation in Syntrophic Acetate-Oxidising Bacteria. Genes (Basel) 2018; 9:genes9040225. [PMID: 29690652 PMCID: PMC5924567 DOI: 10.3390/genes9040225] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/15/2018] [Accepted: 04/16/2018] [Indexed: 01/04/2023] Open
Abstract
Syntrophic acetate oxidation operates close to the thermodynamic equilibrium and very little is known about the participating organisms and their metabolism. Clostridium ultunense is one of the most abundant syntrophic acetate-oxidising bacteria (SAOB) that are found in engineered biogas processes operating with high ammonia concentrations. It has been proven to oxidise acetate in cooperation with hydrogenotrophic methanogens. There is evidence that the Wood-Ljungdahl (WL) pathway plays an important role in acetate oxidation. In this study, we analysed the physiological and metabolic capacities of C. ultunense strain Esp and strain BST on genome scale and conducted a comparative study of all the known characterised SAOB, namely Syntrophaceticus schinkii, Thermacetogenium phaeum, Tepidanaerobacter acetatoxydans, and Pseudothermotoga lettingae. The results clearly indicated physiological robustness to be beneficial for anaerobic digestion environments and revealed unexpected metabolic diversity with respect to acetate oxidation and energy conservation systems. Unlike S. schinkii and Th. phaeum, C. ultunense clearly does not employ the oxidative WL pathway for acetate oxidation, as its genome (and that of P. lettingae) lack important key genes. In both of those species, a proton motive force is likely formed by chemical protons involving putative electron-bifurcating [Fe-Fe] hydrogenases rather than proton pumps. No genes encoding a respiratory Ech (energy-converting hydrogenase), as involved in energy conservation in Th. phaeum and S. schinkii, were identified in C. ultunense and P. lettingae. Moreover, two respiratory complexes sharing similarities to the proton-translocating ferredoxin:NAD⁺ oxidoreductase (Rnf) and the Na⁺ pumping NADH:quinone hydrogenase (NQR) were predicted. These might form a respiratory chain that is involved in the reduction of electron acceptors rather than protons. However, involvement of these complexes in acetate oxidation in C. ultunense and P. lettingae needs further study. This genome-based comparison provides a solid platform for future meta-proteomics and meta-transcriptomics studies and for metabolic engineering, control, and monitoring of SAOB.
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Affiliation(s)
- Shahid Manzoor
- Department of Information Technology, University of the Punjab, Lahore 54 590, Pakistan.
| | - Anna Schnürer
- BioCenter, Department of Molecular Sciences, Box 7015, Swedish University of Agricultural Sciences, SE 750 07 Uppsala, Sweden.
| | - Erik Bongcam-Rudloff
- SLU-Global Bioinformatics Centre, Department of Animal Breeding and Genetics Science, Swedish University of Agricultural Sciences, SE 750 07 Uppsala, Sweden.
| | - Bettina Müller
- BioCenter, Department of Molecular Sciences, Box 7015, Swedish University of Agricultural Sciences, SE 750 07 Uppsala, Sweden.
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26
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Kulik LV, Bertsova YV, Bogachev AV. EPR evidence for a fast-relaxing iron center in Na +-translocating NADH:quinone-oxidoreductase. J Inorg Biochem 2018; 184:15-18. [PMID: 29635097 DOI: 10.1016/j.jinorgbio.2018.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/27/2018] [Accepted: 04/02/2018] [Indexed: 10/17/2022]
Abstract
A paramagnetic Cys4[Fe] center was detected by pulse EPR in Na+-translocating NADH:quinone-oxidoreductase (Na+-NQR) by influence of this center on transverse and longitudinal spin relaxation of Na+-NQR flavin radicals. The oxidation state of the Cys4[Fe] center was Fe3+ in the oxidized and Fe2+ in the reduced Na+-NQR, as deduced from the temperature dependence of spin relaxation rates of different flavin radicals. A high-spin state of iron in the Cys4[Fe] center was assigned to both forms of Na+-NQR.
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Affiliation(s)
- Leonid V Kulik
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia; Novosibirsk State University, Novosibirsk 630090, Russia.
| | - Yulia V Bertsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia
| | - Alexander V Bogachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119234, Russia.
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27
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Dibrov P, Dibrov E, Pierce GN. Na+-NQR (Na+-translocating NADH:ubiquinone oxidoreductase) as a novel target for antibiotics. FEMS Microbiol Rev 2017; 41:653-671. [PMID: 28961953 DOI: 10.1093/femsre/fux032] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/17/2017] [Indexed: 01/08/2023] Open
Abstract
The recent breakthrough in structural studies on Na+-translocating NADH:ubiquinone oxidoreductase (Na+-NQR) from the human pathogen Vibrio cholerae creates a perspective for the systematic design of inhibitors for this unique enzyme, which is the major Na+ pump in aerobic pathogens. Widespread distribution of Na+-NQR among pathogenic species, its key role in energy metabolism, its relation to virulence in different species as well as its absence in eukaryotic cells makes this enzyme especially attractive as a target for prospective antibiotics. In this review, the major biochemical, physiological and, especially, the pharmacological aspects of Na+-NQR are discussed to assess its 'target potential' for drug development. A comparison to other primary bacterial Na+ pumps supports the contention that NQR is a first rate prospective target for a new generation of antimicrobials. A new, narrowly targeted furanone inhibitor of NQR designed in our group is presented as a molecular platform for the development of anti-NQR remedies.
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Affiliation(s)
- Pavel Dibrov
- Department of Microbiology, University of Manitoba, Winnipeg, Canada
| | - Elena Dibrov
- Institute of Cardiovascular Sciences, Albrechtsen Research Centre, St. Boniface Hospital, Winnipeg, Canada.,Department of Physiology and Pathophysiology, Colleges of Medicine and Pharmacy, Faculty of Health Sciences, Winnipeg, Canada
| | - Grant N Pierce
- Institute of Cardiovascular Sciences, Albrechtsen Research Centre, St. Boniface Hospital, Winnipeg, Canada.,Department of Physiology and Pathophysiology, Colleges of Medicine and Pharmacy, Faculty of Health Sciences, Winnipeg, Canada
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28
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Liang P, Rosas-Lemus M, Patel D, Fang X, Tuz K, Juárez O. Dynamic energy dependency of Chlamydia trachomatis on host cell metabolism during intracellular growth: Role of sodium-based energetics in chlamydial ATP generation. J Biol Chem 2017; 293:510-522. [PMID: 29123027 DOI: 10.1074/jbc.m117.797209] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 10/30/2017] [Indexed: 11/06/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular human pathogen responsible for the most prevalent sexually-transmitted infection in the world. For decades C. trachomatis has been considered an "energy parasite" that relies entirely on the uptake of ATP from the host cell. The genomic data suggest that C. trachomatis respiratory chain could produce a sodium gradient that may sustain the energetic demands required for its rapid multiplication. However, this mechanism awaits experimental confirmation. Moreover, the relationship of chlamydiae with the host cell, in particular its energy dependence, is not well understood. In this work, we are showing that C. trachomatis has an active respiratory metabolism that seems to be coupled to the sodium-dependent synthesis of ATP. Moreover, our results show that the inhibition of mitochondrial ATP synthesis at an early stage decreases the rate of infection and the chlamydial inclusion size. In contrast, the inhibition of the chlamydial respiratory chain at mid-stage of the infection cycle decreases the inclusion size but has no effect on infection rate. Remarkably, the addition of monensin, a Na+/H+ exchanger, completely halts the infection. Altogether, our data indicate that chlamydial development has a dynamic relationship with the mitochondrial metabolism of the host, in which the bacterium mostly depends on host ATP synthesis at an early stage, and at later stages it can sustain its own energy needs through the formation of a sodium gradient.
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Affiliation(s)
- Pingdong Liang
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Mónica Rosas-Lemus
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Dhwani Patel
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Xuan Fang
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Karina Tuz
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Oscar Juárez
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616
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29
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Fang X, Liang P, Raba DA, Rosas-Lemus M, Chakravarthy S, Tuz K, Juárez O. Kinetic characterization of Vibrio cholerae ApbE: Substrate specificity and regulatory mechanisms. PLoS One 2017; 12:e0186805. [PMID: 29065131 PMCID: PMC5655446 DOI: 10.1371/journal.pone.0186805] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/06/2017] [Indexed: 12/20/2022] Open
Abstract
ApbE is a member of a novel family of flavin transferases that incorporates flavin mononucleotide (FMN) to subunits of diverse respiratory complexes, which fulfill important homeostatic functions. In this work a detailed characterization of Vibrio cholerae ApbE physiologic activity, substrate specificity and pH dependency was carried out. The data obtained show novel characteristics of the regulation and function of this family. For instance, our experiments indicate that divalent cations are essential for ApbE function, and that the selectivity depends largely on size and the coordination sphere of the cation. Our data also show that ApbE regulation by pH, ADP and potassium is an important mechanism that enhances the adaptation, survival and colonization of V. cholerae in the small intestine. Moreover, studies of the pH-dependency of the activity show that the reaction is favored under alkaline conditions, with a pKa of 8.4. These studies, together with sequence and structure analysis allowed us to identify His257, which is absolutely conserved in the family, as a candidate for the residue whose deprotonation controls the activity. Remarkably, the mutant H257G abolished the flavin transfer activity, strongly indicating that this residue plays an important role in the catalytic mechanism of ApbE.
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Affiliation(s)
- Xuan Fang
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
| | - Pingdong Liang
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
| | - Daniel Alexander Raba
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
| | - Mónica Rosas-Lemus
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
| | - Srinivas Chakravarthy
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
- Biophysics Collaborative Access Team, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois, United States of America
| | - Karina Tuz
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
| | - Oscar Juárez
- Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois, United States of America
- * E-mail:
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30
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Ito T, Murai M, Ninokura S, Kitazumi Y, Mezic KG, Cress BF, Koffas MAG, Morgan JE, Barquera B, Miyoshi H. Identification of the binding sites for ubiquinone and inhibitors in the Na +-pumping NADH-ubiquinone oxidoreductase from Vibrio cholerae by photoaffinity labeling. J Biol Chem 2017; 292:7727-7742. [PMID: 28298441 DOI: 10.1074/jbc.m117.781393] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/11/2017] [Indexed: 12/30/2022] Open
Abstract
The Na+-pumping NADH-quinone oxidoreductase (Na+-NQR) is the first enzyme of the respiratory chain and the main ion transporter in many marine and pathogenic bacteria, including Vibrio cholerae The V. cholerae Na+-NQR has been extensively studied, but its binding sites for ubiquinone and inhibitors remain controversial. Here, using a photoreactive ubiquinone PUQ-3 as well as two aurachin-type inhibitors [125I]PAD-1 and [125I]PAD-2 and photoaffinity labeling experiments on the isolated enzyme, we demonstrate that the ubiquinone ring binds to the NqrA subunit in the regions Leu-32-Met-39 and Phe-131-Lys-138, encompassing the rear wall of a predicted ubiquinone-binding cavity. The quinolone ring and alkyl side chain of aurachin bound to the NqrB subunit in the regions Arg-43-Lys-54 and Trp-23-Gly-89, respectively. These results indicate that the binding sites for ubiquinone and aurachin-type inhibitors are in close proximity but do not overlap one another. Unexpectedly, although the inhibitory effects of PAD-1 and PAD-2 were almost completely abolished by certain mutations in NqrB (i.e. G140A and E144C), the binding reactivities of [125I]PAD-1 and [125I]PAD-2 to the mutated enzymes were unchanged compared with those of the wild-type enzyme. We also found that photoaffinity labeling by [125I]PAD-1 and [125I]PAD-2, rather than being competitively suppressed in the presence of other inhibitors, is enhanced under some experimental conditions. To explain these apparently paradoxical results, we propose models for the catalytic reaction of Na+-NQR and its interactions with inhibitors on the basis of the biochemical and biophysical results reported here and in previous work.
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Affiliation(s)
- Takeshi Ito
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan and
| | - Masatoshi Murai
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan and
| | - Satoshi Ninokura
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan and
| | - Yuki Kitazumi
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan and
| | - Katherine G Mezic
- the Departments of Biological Sciences and.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Brady F Cress
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180.,Chemical and Biological Engineering
| | - Mattheos A G Koffas
- the Departments of Biological Sciences and.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180.,Chemical and Biological Engineering
| | - Joel E Morgan
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Blanca Barquera
- the Departments of Biological Sciences and.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Hideto Miyoshi
- From the Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan and
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31
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Tuz K, Li C, Fang X, Raba DA, Liang P, Minh DDL, Juárez O. Identification of the Catalytic Ubiquinone-binding Site of Vibrio cholerae Sodium-dependent NADH Dehydrogenase: A NOVEL UBIQUINONE-BINDING MOTIF. J Biol Chem 2017; 292:3039-3048. [PMID: 28053088 DOI: 10.1074/jbc.m116.770982] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 12/29/2016] [Indexed: 11/06/2022] Open
Abstract
The sodium-dependent NADH dehydrogenase (Na+-NQR) is a key component of the respiratory chain of diverse prokaryotic species, including pathogenic bacteria. Na+-NQR uses the energy released by electron transfer between NADH and ubiquinone (UQ) to pump sodium, producing a gradient that sustains many essential homeostatic processes as well as virulence factor secretion and the elimination of drugs. The location of the UQ binding site has been controversial, with two main hypotheses that suggest that this site could be located in the cytosolic subunit A or in the membrane-bound subunit B. In this work, we performed alanine scanning mutagenesis of aromatic residues located in transmembrane helices II, IV, and V of subunit B, near glycine residues 140 and 141. These two critical glycine residues form part of the structures that regulate the site's accessibility. Our results indicate that the elimination of phenylalanine residue 211 or 213 abolishes the UQ-dependent activity, produces a leak of electrons to oxygen, and completely blocks the binding of UQ and the inhibitor HQNO. Molecular docking calculations predict that UQ interacts with phenylalanine 211 and pinpoints the location of the binding site in the interface of subunits B and D. The mutagenesis and structural analysis allow us to propose a novel UQ-binding motif, which is completely different compared with the sites of other respiratory photosynthetic complexes. These results are essential to understanding the electron transfer pathways and mechanism of Na+-NQR catalysis.
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Affiliation(s)
- Karina Tuz
- From the Departments of Biological Sciences and
| | - Chen Li
- Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616
| | - Xuan Fang
- From the Departments of Biological Sciences and
| | | | | | - David D L Minh
- Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616
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32
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Vorburger T, Nedielkov R, Brosig A, Bok E, Schunke E, Steffen W, Mayer S, Götz F, Möller HM, Steuber J. Role of the Na(+)-translocating NADH:quinone oxidoreductase in voltage generation and Na(+) extrusion in Vibrio cholerae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:473-82. [PMID: 26721205 DOI: 10.1016/j.bbabio.2015.12.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/25/2015] [Accepted: 12/16/2015] [Indexed: 01/05/2023]
Abstract
For Vibrio cholerae, the coordinated import and export of Na(+) is crucial for adaptation to habitats with different osmolarities. We investigated the Na(+)-extruding branch of the sodium cycle in this human pathogen by in vivo (23)Na-NMR spectroscopy. The Na(+) extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR). In a V. cholerae deletion mutant devoid of the Na(+)-NQR encoding genes (nqrA-F), rates of respiratory Na(+) extrusion were decreased by a factor of four, but the cytoplasmic Na(+) concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (ΔΨ, inside negative) and did not grow under hypoosmotic conditions at pH8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na(+)/H(+) antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na(+) concentrations, the Na(+)-NQR is crucial for generation of a transmembrane voltage to drive the import of H(+) by electrogenic Na(+)/H(+) antiporters. Our study provides the basis to understand the role of the Na(+)-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na(+) pump for respiration.
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Affiliation(s)
- Thomas Vorburger
- Institute of Microbiology, University of Hohenheim (Stuttgart), Garbenstraße 30, 70599 Stuttgart, Germany
| | - Ruslan Nedielkov
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Alexander Brosig
- Department of Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Eva Bok
- Institute of Microbiology, University of Hohenheim (Stuttgart), Garbenstraße 30, 70599 Stuttgart, Germany
| | - Emina Schunke
- Institute of Microbiology, University of Hohenheim (Stuttgart), Garbenstraße 30, 70599 Stuttgart, Germany
| | - Wojtek Steffen
- Institute of Microbiology, University of Hohenheim (Stuttgart), Garbenstraße 30, 70599 Stuttgart, Germany
| | - Sonja Mayer
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Microbial Genetics, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Friedrich Götz
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Microbial Genetics, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Heiko M Möller
- Department of Chemistry, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Julia Steuber
- Institute of Microbiology, University of Hohenheim (Stuttgart), Garbenstraße 30, 70599 Stuttgart, Germany.
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33
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Castro PJ, Silva AF, Marreiros BC, Batista AP, Pereira MM. Respiratory complex I: A dual relation with H(+) and Na(+)? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:928-37. [PMID: 26711319 DOI: 10.1016/j.bbabio.2015.12.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 12/10/2015] [Accepted: 12/17/2015] [Indexed: 10/22/2022]
Abstract
Respiratory complex I couples NADH:quinone oxidoreduction to ion translocation across the membrane, contributing to the buildup of the transmembrane difference of electrochemical potential. H(+) is well recognized to be the coupling ion of this system but some studies suggested that this role could be also performed by Na(+). We have previously observed NADH-driven Na(+) transport opposite to H(+) translocation by menaquinone-reducing complexes I, which indicated a Na(+)/H(+) antiporter activity in these systems. Such activity was also observed for the ubiquinone-reducing mitochondrial complex I in its deactive form. The relation of Na(+) with complex I may not be surprising since the enzyme has three subunits structurally homologous to bona fide Na(+)/H(+) antiporters and translocation of H(+) and Na(+) ions has been described for members of most types of ion pumps and transporters. Moreover, no clearly distinguishable motifs for the binding of H(+) or Na(+) have been recognized yet. We noticed that in menaquinone-reducing complexes I, less energy is available for ion translocation, compared to ubiquinone-reducing complexes I. Therefore, we hypothesized that menaquinone-reducing complexes I perform Na(+)/H(+) antiporter activity in order to achieve the stoichiometry of 4H(+)/2e(-). In agreement, the organisms that use ubiquinone, a high potential quinone, would have kept such Na(+)/H(+) antiporter activity, only operative under determined conditions. This would imply a physiological role(s) of complex I besides a simple "coupling" of a redox reaction and ion transport, which could account for the sophistication of this enzyme. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.
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Affiliation(s)
- Paulo J Castro
- Instituto de Tecnologia Química e Biológica, António Xavier, Universidade Nova de Lisboa, Av. da Republica EAN, 2780-157 Oeiras, Portugal
| | - Andreia F Silva
- Instituto de Tecnologia Química e Biológica, António Xavier, Universidade Nova de Lisboa, Av. da Republica EAN, 2780-157 Oeiras, Portugal
| | - Bruno C Marreiros
- Instituto de Tecnologia Química e Biológica, António Xavier, Universidade Nova de Lisboa, Av. da Republica EAN, 2780-157 Oeiras, Portugal
| | - Ana P Batista
- Instituto de Tecnologia Química e Biológica, António Xavier, Universidade Nova de Lisboa, Av. da Republica EAN, 2780-157 Oeiras, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica, António Xavier, Universidade Nova de Lisboa, Av. da Republica EAN, 2780-157 Oeiras, Portugal.
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34
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Comprehensive Genomic Analyses of the OM43 Clade, Including a Novel Species from the Red Sea, Indicate Ecotype Differentiation among Marine Methylotrophs. Appl Environ Microbiol 2015; 82:1215-1226. [PMID: 26655752 DOI: 10.1128/aem.02852-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/03/2015] [Indexed: 12/16/2022] Open
Abstract
The OM43 clade within the family Methylophilaceae of Betaproteobacteria represents a group of methylotrophs that play important roles in the metabolism of C1 compounds in marine environments and other aquatic environments around the globe. Using dilution-to-extinction cultivation techniques, we successfully isolated a novel species of this clade (here designated MBRS-H7) from the ultraoligotrophic open ocean waters of the central Red Sea. Phylogenomic analyses indicate that MBRS-H7 is a novel species that forms a distinct cluster together with isolate KB13 from Hawaii (Hawaii-Red Sea [H-RS] cluster) that is separate from the cluster represented by strain HTCC2181 (from the Oregon coast). Phylogenetic analyses using the robust 16S-23S internal transcribed spacer revealed a potential ecotype separation of the marine OM43 clade members, which was further confirmed by metagenomic fragment recruitment analyses that showed trends of higher abundance in low-chlorophyll and/or high-temperature provinces for the H-RS cluster but a preference for colder, highly productive waters for the HTCC2181 cluster. This potential environmentally driven niche differentiation is also reflected in the metabolic gene inventories, which in the case of the H-RS cluster include those conferring resistance to high levels of UV irradiation, temperature, and salinity. Interestingly, we also found different energy conservation modules between these OM43 subclades, namely, the existence of the NADH:quinone oxidoreductase complex I (NUO) system in the H-RS cluster and the nonhomologous NADH:quinone oxidoreductase (NQR) system in the HTCC2181 cluster, which might have implications for their overall energetic yields.
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35
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Belevich NP, Bertsova YV, Verkhovskaya ML, Baykov AA, Bogachev AV. Identification of the coupling step in Na(+)-translocating NADH:quinone oxidoreductase from real-time kinetics of electron transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:141-149. [PMID: 26655930 DOI: 10.1016/j.bbabio.2015.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 11/02/2015] [Accepted: 12/03/2015] [Indexed: 10/22/2022]
Abstract
Bacterial Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) uses a unique set of prosthetic redox groups-two covalently bound FMN residues, a [2Fe-2S] cluster, FAD, riboflavin and a Cys4[Fe] center-to catalyze electron transfer from NADH to ubiquinone in a reaction coupled with Na(+) translocation across the membrane. Here we used an ultra-fast microfluidic stopped-flow instrument to determine rate constants and the difference spectra for the six consecutive reaction steps of Vibrio harveyi Na(+)-NQR reduction by NADH. The instrument, with a dead time of 0.25 ms and optical path length of 1 cm allowed collection of visible spectra in 50-μs intervals. By comparing the spectra of reaction steps with the spectra of known redox transitions of individual enzyme cofactors, we were able to identify the chemical nature of most intermediates and the sequence of electron transfer events. A previously unknown spectral transition was detected and assigned to the Cys4[Fe] center reduction. Electron transfer from the [2Fe-2S] cluster to the Cys4[Fe] center and all subsequent steps were markedly accelerated when Na(+) concentration was increased from 20 μM to 25 mM, suggesting coupling of the former step with tight Na(+) binding to or occlusion by the enzyme. An alternating access mechanism was proposed to explain electron transfer between subunits NqrF and NqrC. According to the proposed mechanism, the Cys4[Fe] center is alternatively exposed to either side of the membrane, allowing the [2Fe-2S] cluster of NqrF and the FMN residue of NqrC to alternatively approach the Cys4[Fe] center from different sides of the membrane.
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Affiliation(s)
- Nikolai P Belevich
- Institute of Biotechnology, University of Helsinki, PO Box 65, Viikinkaari 1, FIN-00014, Finland
| | - Yulia V Bertsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Marina L Verkhovskaya
- Institute of Biotechnology, University of Helsinki, PO Box 65, Viikinkaari 1, FIN-00014, Finland
| | - Alexander A Baykov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Alexander V Bogachev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia.
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Tuz K, Mezic KG, Xu T, Barquera B, Juárez O. The Kinetic Reaction Mechanism of the Vibrio cholerae Sodium-dependent NADH Dehydrogenase. J Biol Chem 2015; 290:20009-21. [PMID: 26004776 DOI: 10.1074/jbc.m115.658773] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Indexed: 11/06/2022] Open
Abstract
The sodium-dependent NADH dehydrogenase (Na(+)-NQR) is the main ion transporter in Vibrio cholerae. Its activity is linked to the operation of the respiratory chain and is essential for the development of the pathogenic phenotype. Previous studies have described different aspects of the enzyme, including the electron transfer pathways, sodium pumping structures, cofactor and subunit composition, among others. However, the mechanism of the enzyme remains to be completely elucidated. In this work, we have studied the kinetic mechanism of Na(+)-NQR with the use of steady state kinetics and stopped flow analysis. Na(+)-NQR follows a hexa-uni ping-pong mechanism, in which NADH acts as the first substrate, reacts with the enzyme, and the oxidized NAD leaves the catalytic site. In this conformation, the enzyme is able to capture two sodium ions and transport them to the external side of the membrane. In the last step, ubiquinone is bound and reduced, and ubiquinol is released. Our data also demonstrate that the catalytic cycle involves two redox states, the three- and five-electron reduced forms. A model that gathers all available information is proposed to explain the kinetic mechanism of Na(+)-NQR. This model provides a background to understand the current structural and functional information.
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Affiliation(s)
- Karina Tuz
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616 and
| | - Katherine G Mezic
- the Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Tianhao Xu
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616 and
| | - Blanca Barquera
- the Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Oscar Juárez
- From the Department of Biological Sciences, Illinois Institute of Technology, Chicago, Illinois 60616 and
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Tokunou Y, Hashimoto K, Okamoto A. Extracellular Electron Transport Scarcely Accumulates Proton Motive Force inShewanella oneidensisMR-1. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2015. [DOI: 10.1246/bcsj.20140407] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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The Staphylococcus aureus NuoL-like protein MpsA contributes to the generation of membrane potential. J Bacteriol 2014; 197:794-806. [PMID: 25448817 DOI: 10.1128/jb.02127-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In aerobic microorganisms, the entry point of respiratory electron transfer is represented by the NADH:quinone oxidoreductase. The enzyme couples the oxidation of NADH with the reduction of quinone. In the type 1 NADH:quinone oxidoreductase (Ndh1), this reaction is accompanied by the translocation of cations, such as H(+) or Na(+). In Escherichia coli, cation translocation is accomplished by the subunit NuoL, thus generating membrane potential (Δψ). Some microorganisms achieve NADH oxidation by the alternative, nonelectrogenic type 2 NADH:quinone oxidoreductase (Ndh2), which is not cation translocating. Since these enzymes had not been described in Staphylococcus aureus, the goal of this study was to identify proteins operating in the NADH:quinone segment of its respiratory chain. We demonstrated that Ndh2 represents a NADH:quinone oxidoreductase in S. aureus. Additionally, we identified a hypothetical protein in S. aureus showing sequence similarity to the proton-translocating subunit NuoL of complex I in E. coli: the NuoL-like protein MpsA. Mutants with deletion of the nuoL-like gene mpsA and its corresponding operon, mpsABC (mps for membrane potential-generating system), exhibited a small-colony-variant-like phenotype and were severely affected in Δψ and oxygen consumption rates. The MpsABC proteins did not confer NADH oxidation activity. Using an Na(+)/H(+) antiporter-deficient E. coli strain, we could show that MpsABC constitute a cation-translocating system capable of Na(+) transport. Our study demonstrates that MpsABC represent an important functional system of the respiratory chain of S. aureus that acts as an electrogenic unit responsible for the generation of Δψ.
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Abstract
The emergence and spread of drug-resistant pathogens and our inability to develop new antimicrobials to overcome resistance has inspired scientists to consider new targets for drug development. Cellular bioenergetics is an area showing promise for the development of new antimicrobials, particularly in the discovery of new anti-tuberculosis drugs where several new compounds have entered clinical trials. In this review, we have examined the bioenergetics of various bacterial pathogens, highlighting the versatility of electron donor and acceptor utilisation and the modularity of electron transport chain components in bacteria. In addition to re-examining classical concepts, we explore new literature that reveals the intricacies of pathogen energetics, for example, how Salmonella enterica and Campylobacter jejuni exploit host and microbiota to derive powerful electron donors and sinks; the strategies Mycobacterium tuberculosis and Pseudomonas aeruginosa use to persist in lung tissues; and the importance of sodium energetics and electron bifurcation in the chemiosmotic anaerobe Fusobacterium nucleatum. A combination of physiological, biochemical, and pharmacological data suggests that, in addition to the clinically-approved target F1Fo-ATP synthase, NADH dehydrogenase type II, succinate dehydrogenase, hydrogenase, cytochrome bd oxidase, and menaquinone biosynthesis pathways are particularly promising next-generation drug targets. The realisation of cellular energetics as a rich target space for the development of new antimicrobials will be dependent upon gaining increased understanding of the energetic processes utilised by pathogens in host environments and the ability to design bacterial-specific inhibitors of these processes.
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Tang S, Bai J, Yin H, Ye J, Peng H, Liu Z, Dang Z. Tea saponin enhanced biodegradation of decabromodiphenyl ether by Brevibacillus brevis. CHEMOSPHERE 2014; 114:255-261. [PMID: 25113210 DOI: 10.1016/j.chemosphere.2014.05.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 05/01/2014] [Accepted: 05/03/2014] [Indexed: 06/03/2023]
Abstract
Decabromodiphenyl ether (BDE209) is a ubiquitous persistent pollutant and has contaminated the environment worldwide. To accelerate BDE209 elimination and reveal the mechanism concerned, the biosurfactant tea saponin enhanced degradation of BDE209 by Brevibacillus brevis was conducted. The results revealed that tea saponin could efficiently increase the solubility of BDE209 in mineral salts medium and improve its biodegradation. The degradation efficiency of 0.5 mg L(-1) BDE209 by 1 g L(-1) biomass with surfactant was up to 55% within 5d. Contact time was a significant factor for BDE209 biodegradation. BDE209 biodegradation was coupled with bioaccumulation, ion release and utilization, and debromination to lower brominated PBDE metabolites. During the biodegradation process, B. brevis metabolically released Na(+), NH4(+), NO2(-) and Cl(-), and utilized the nutrient ions Mg(2+), PO4(3-) and SO4(2-). GC-MS analysis revealed that the structure of BDE209 changed under the action of strain and nonabromodiphenyl ethers (BDE-208, -207 and -206), octabromodiphenyl ethers (BDE-203, -197 and -196) and heptabromodiphenyl ether (BDE-183) were generated by debromination.
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Affiliation(s)
- Shaoyu Tang
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, College of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, China
| | - Jieqiong Bai
- Department of Environmental Engineering, Jinan University, Guangzhou 510632, Guangdong, China
| | - Hua Yin
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, College of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, China.
| | - Jinshao Ye
- Department of Environmental Engineering, Jinan University, Guangzhou 510632, Guangdong, China.
| | - Hui Peng
- Department of Chemistry, Jinan University, Guangzhou 510632, Guangdong, China
| | - Zehua Liu
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, College of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, China
| | - Zhi Dang
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, College of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, China
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The sodium pumping NADH:quinone oxidoreductase (Na⁺-NQR), a unique redox-driven ion pump. J Bioenerg Biomembr 2014; 46:289-98. [PMID: 25052842 DOI: 10.1007/s10863-014-9565-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Accepted: 07/03/2014] [Indexed: 12/15/2022]
Abstract
The Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) is a unique Na(+) pumping respiratory complex found only in prokaryotes, that plays a key role in the metabolism of marine and pathogenic bacteria, including Vibrio cholerae and other human pathogens. Na(+)-NQR is the main entrance for reducing equivalents into the respiratory chain of these bacteria, catalyzing the oxidation of NADH and the reduction of quinone, the free energy of this redox reaction drives the selective translocation of Na(+) across the cell membrane, which energizes key cellular processes. In this review we summarize the unique properties of Na(+)-NQR in terms of its redox cofactor composition, electron transfer reactions and a possible mechanism of coupling and pumping.
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Cell-secreted flavins bound to membrane cytochromes dictate electron transfer reactions to surfaces with diverse charge and pH. Sci Rep 2014; 4:5628. [PMID: 25012073 PMCID: PMC4092373 DOI: 10.1038/srep05628] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 06/18/2014] [Indexed: 11/08/2022] Open
Abstract
The variety of solid surfaces to and from which microbes can deliver electrons by extracellular electron transport (EET) processes via outer-membrane c-type cytochromes (OM c-Cyts) expands the importance of microbial respiration in natural environments and industrial applications. Here, we demonstrate that the bifurcated EET pathway of OM c-Cyts sustains the diversity of the EET surface in Shewanella oneidensis MR-1 via specific binding with cell-secreted flavin mononucleotide (FMN) and riboflavin (RF). Microbial current production and whole-cell differential pulse voltammetry revealed that RF and FMN enhance EET as bound cofactors in a similar manner. Conversely, FMN and RF were clearly differentiated in the EET enhancement by gene-deletion of OM c-Cyts and the dependency of the electrode potential and pH. These results indicate that RF and FMN have specific binding sites in OM c-Cyts and highlight the potential roles of these flavin-cytochrome complexes in controlling the rate of electron transfer to surfaces with diverse potential and pH.
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Strickland M, Juárez O, Neehaul Y, Cook DA, Barquera B, Hellwig P. The conformational changes induced by ubiquinone binding in the Na+-pumping NADH:ubiquinone oxidoreductase (Na+-NQR) are kinetically controlled by conserved glycines 140 and 141 of the NqrB subunit. J Biol Chem 2014; 289:23723-33. [PMID: 25006248 DOI: 10.1074/jbc.m114.574640] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Na(+)-pumping NADH:ubiquinone oxidoreductase (Na(+)-NQR) is responsible for maintaining a sodium gradient across the inner bacterial membrane. This respiratory enzyme, which couples sodium pumping to the electron transfer between NADH and ubiquinone, is not present in eukaryotes and as such could be a target for antibiotics. In this paper it is shown that the site of ubiquinone reduction is conformationally coupled to the NqrB subunit, which also hosts the final cofactor in the electron transport chain, riboflavin. Previous work showed that mutations in conserved NqrB glycine residues 140 and 141 affect ubiquinone reduction and the proper functioning of the sodium pump. Surprisingly, these mutants did not affect the dissociation constant of ubiquinone or its analog HQNO (2-n-heptyl-4-hydroxyquinoline N-oxide) from Na(+)-NQR, which indicates that these residues do not participate directly in the ubiquinone binding site but probably control its accessibility. Indeed, redox-induced difference spectroscopy showed that these mutations prevented the conformational change involved in ubiquinone binding but did not modify the signals corresponding to bound ubiquinone. Moreover, data are presented that demonstrate the NqrA subunit is able to bind ubiquinone but with a low non-catalytically relevant affinity. It is also suggested that Na(+)-NQR contains a single catalytic ubiquinone binding site and a second site that can bind ubiquinone but is not active.
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Affiliation(s)
- Madeleine Strickland
- From the Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CNRS Université de Strasbourg, Strasbourg, France, 67000 and
| | - Oscar Juárez
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Yashvin Neehaul
- From the Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CNRS Université de Strasbourg, Strasbourg, France, 67000 and
| | - Darcie A Cook
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Blanca Barquera
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Petra Hellwig
- From the Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CNRS Université de Strasbourg, Strasbourg, France, 67000 and
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Characterization of the RnfB and RnfG subunits of the Rnf complex from the archaeon Methanosarcina acetivorans. PLoS One 2014; 9:e97966. [PMID: 24836163 PMCID: PMC4023990 DOI: 10.1371/journal.pone.0097966] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/26/2014] [Indexed: 11/20/2022] Open
Abstract
Rnf complexes are redox-driven ion pumps identified in diverse species from the domains Bacteria and Archaea, biochemical characterizations of which are reported for two species from the domain Bacteria. Here, we present characterizations of the redox-active subunits RnfG and RnfB from the Rnf complex of Methanosarcina acetivorans, an acetate-utilizing methane-producing species from the domain Archaea. The purified RnfG subunit produced in Escherichia coli fluoresced in SDS-PAGE gels under UV illumination and showed a UV-visible spectrum typical of flavoproteins. The Thr166Gly variant of RnfG was colorless and failed to fluoresce under UV illumination confirming a role for Thr166 in binding FMN. Redox titration of holo-RnfG revealed a midpoint potential of −129 mV for FMN with n = 2. The overproduced RnfG was primarily localized to the membrane of E. coli and the sequence contained a transmembrane helix. A topological analysis combining reporter protein fusion and computer predictions indicated that the C-terminal domain containing FMN is located on the outer aspect of the cytoplasmic membrane. The purified RnfB subunit produced in E. coli showed a UV-visible spectrum typical of iron-sulfur proteins. The EPR spectra of reduced RnfB featured a broad spectral shape with g values (2.06, 1.94, 1.90, 1.88) characteristic of magnetically coupled 3Fe-4S and 4Fe-4S clusters in close agreement with the iron and acid-labile sulfur content. The ferredoxin specific to the aceticlastic pathway served as an electron donor to RnfB suggesting this subunit is the entry point of electrons to the Rnf complex. The results advance an understanding of the organization and biochemical properties of the Rnf complex and lay a foundation for further understanding the overall mechanism in the pathway of methane formation from acetate.
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45
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Origin and evolution of the sodium -pumping NADH: ubiquinone oxidoreductase. PLoS One 2014; 9:e96696. [PMID: 24809444 PMCID: PMC4014512 DOI: 10.1371/journal.pone.0096696] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 04/11/2014] [Indexed: 11/27/2022] Open
Abstract
The sodium -pumping NADH: ubiquinone oxidoreductase (Na+-NQR) is the main ion pump and the primary entry site for electrons into the respiratory chain of many different types of pathogenic bacteria. This enzymatic complex creates a transmembrane gradient of sodium that is used by the cell to sustain ionic homeostasis, nutrient transport, ATP synthesis, flagellum rotation and other essential processes. Comparative genomics data demonstrate that the nqr operon, which encodes all Na+-NQR subunits, is found in a large variety of bacterial lineages with different habitats and metabolic strategies. Here we studied the distribution, origin and evolution of this enzymatic complex. The molecular phylogenetic analyses and the organizations of the nqr operon indicate that Na+-NQR evolved within the Chlorobi/Bacteroidetes group, after the duplication and subsequent neofunctionalization of the operon that encodes the homolog RNF complex. Subsequently, the nqr operon dispersed through multiple horizontal transfer events to other bacterial lineages such as Chlamydiae, Planctomyces and α, β, γ and δ -proteobacteria. Considering the biochemical properties of the Na+-NQR complex and its physiological role in different bacteria, we propose a detailed scenario to explain the molecular mechanisms that gave rise to its novel redox- dependent sodium -pumping activity. Our model postulates that the evolution of the Na+-NQR complex involved a functional divergence from its RNF homolog, following the duplication of the rnf operon, the loss of the rnfB gene and the recruitment of the reductase subunit of an aromatic monooxygenase.
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46
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Mayer F, Müller V. Adaptations of anaerobic archaea to life under extreme energy limitation. FEMS Microbiol Rev 2014; 38:449-72. [DOI: 10.1111/1574-6976.12043] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 08/30/2013] [Accepted: 09/03/2013] [Indexed: 11/28/2022] Open
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Cation transport by the respiratory NADH:quinone oxidoreductase (complex I): facts and hypotheses. Biochem Soc Trans 2014; 41:1280-7. [PMID: 24059520 DOI: 10.1042/bst20130024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The respiratory complex I (electrogenic NADH:quinone oxidoreductase) has been considered to act exclusively as a H+ pump. This was questioned when the search for the NADH-driven respiratory Na+ pump in Klebsiella pneumoniae initiated by Peter Dimroth led to the discovery of a Na+-translocating complex in this enterobacterium. The 3D structures of complex I from different organisms support the idea that the mechanism of cation transport by complex I involves conformational changes of the membrane-bound NuoL, NuoM and NuoN subunits. In vitro methods to follow Na+ transport were compared with in vivo approaches to test whether complex I, or its individual NuoL, NuoM or NuoN subunits, extrude Na+ from the cytoplasm to the periplasm of bacterial host cells. The truncated NuoL subunit of the Escherichia coli complex I which comprises amino acids 1-369 exhibits Na+ transport activity in vitro. This observation, together with an analysis of putative cation channels in NuoL, suggests that there exists in NuoL at least one continuous pathway for cations lined by amino acid residues from transmembrane segments 3, 4, 5, 7 and 8. Finally, we discuss recent studies on Na+ transport by mitochondrial complex I with respect to its putative role in the cycling of Na+ ions across the inner mitochondrial membrane.
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Schurig-Briccio LA, Yano T, Rubin H, Gennis RB. Characterization of the type 2 NADH:menaquinone oxidoreductases from Staphylococcus aureus and the bactericidal action of phenothiazines. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:954-63. [PMID: 24709059 DOI: 10.1016/j.bbabio.2014.03.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 02/01/2023]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is currently one of the principal multiple drug resistant bacterial pathogens causing serious infections, many of which are life-threatening. Consequently, new therapeutic targets are required to combat such infections. In the current work, we explore the type 2 Nicotinamide adenine dinucleotide reduced form (NADH) dehydrogenases (NDH-2s) as possible drug targets and look at the effects of phenothiazines, known to inhibit NDH-2 from Mycobacterium tuberculosis. NDH-2s are monotopic membrane proteins that catalyze the transfer of electrons from NADH via flavin adenine dinucleotide (FAD) to the quinone pool. They are required for maintaining the NADH/Nicotinamide adenine dinucleotide (NAD(+)) redox balance and contribute indirectly to the generation of proton motive force. NDH-2s are not present in mammals, but are the only form of respiratory NADH dehydrogenase in several pathogens, including S. aureus. In this work, the two putative ndh genes present in the S. aureus genome were identified, cloned and expressed, and the proteins were purified and characterized. Phenothiazines were shown to inhibit both of the S. aureus NDH-2s with half maximal inhibitory concentration (IC50) values as low as 8μM. However, evaluating the effects of phenothiazines on whole cells of S. aureus was complicated by the fact that they are also acting as uncouplers of oxidative phosphorylation. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
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Affiliation(s)
- Lici A Schurig-Briccio
- Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA
| | - Takahiro Yano
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Harvey Rubin
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert B Gennis
- Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA.
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Omsland A, Sixt BS, Horn M, Hackstadt T. Chlamydial metabolism revisited: interspecies metabolic variability and developmental stage-specific physiologic activities. FEMS Microbiol Rev 2014; 38:779-801. [PMID: 24484402 DOI: 10.1111/1574-6976.12059] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/08/2014] [Accepted: 01/13/2014] [Indexed: 01/07/2023] Open
Abstract
Chlamydiae are a group of obligate intracellular bacteria comprising important human and animal pathogens as well as symbionts of ubiquitous protists. They are characterized by a developmental cycle including two main morphologically and physiologically distinct stages, the replicating reticulate body and the infectious nondividing elementary body. In this review, we reconstruct the history of studies that have led to our current perception of chlamydial physiology, focusing on their energy and central carbon metabolism. We then compare the metabolic capabilities of pathogenic and environmental chlamydiae highlighting interspecies variability among the metabolically more flexible environmental strains. We discuss recent findings suggesting that chlamydiae may not live as energy parasites throughout the developmental cycle and that elementary bodies are not metabolically inert but exhibit metabolic activity under appropriate axenic conditions. The observed host-free metabolic activity of elementary bodies may reflect adequate recapitulation of the intracellular environment, but there is evidence that this activity is biologically relevant and required for extracellular survival and maintenance of infectivity. The recent discoveries call for a reconsideration of chlamydial metabolism and future in-depth analyses to better understand how species- and stage-specific differences in chlamydial physiology may affect virulence, tissue tropism, and host adaptation.
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Affiliation(s)
- Anders Omsland
- Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, NIAID, NIH, Hamilton, MT, USA
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50
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Localization-controlled specificity of FAD:threonine flavin transferases in Klebsiella pneumoniae and its implications for the mechanism of Na(+)-translocating NADH:quinone oxidoreductase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:1122-9. [PMID: 24361839 DOI: 10.1016/j.bbabio.2013.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/04/2013] [Accepted: 12/13/2013] [Indexed: 12/22/2022]
Abstract
The Klebsiella pneumoniae genome contains genes for two putative flavin transferase enzymes (ApbE1 and ApbE2) that add FMN to protein Thr residues. ApbE1, but not ApbE2, has a periplasm-addressing signal sequence. The genome also contains genes for three target proteins with the Dxx(s/t)gAT flavinylation motif: two subunits of Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR), and a 99.5kDa protein, KPK_2907, with a previously unknown function. We show here that KPK_2907 is an active cytoplasmically-localized fumarate reductase. K. pneumoniae cells with an inactivated kpk_2907 gene lack cytoplasmic fumarate reductase activity, while retaining this activity in the membrane fraction. Complementation of the mutant strain with a kpk_2907-containing plasmid resulted in a complete recovery of cytoplasmic fumarate reductase activity. KPK_2907 produced in Escherichia coli cells contains 1mol/mol each of covalently bound FMN, noncovalently bound FMN and noncovalently bound FAD. Lesion in the ApbE1 gene in K. pneumoniae resulted in inactive Na(+)-NQR, but cytoplasmic fumarate reductase activity remained unchanged. On the contrary, lesion in the ApbE2 gene abolished the fumarate reductase but not the Na(+)-NQR activity. Both activities could be restored by transformation of the ApbE1- or ApbE2-deficient K. pneumoniae strains with plasmids containing the Vibrio cholerae apbE gene with or without the periplasm-directing signal sequence, respectively. Our data thus indicate that ApbE1 and ApbE2 bind FMN to Na(+)-NQR and fumarate reductase, respectively, and that, contrary to the presently accepted view, the FMN residues are on the periplasmic side of Na(+)-NQR. A new, "electron loop" mechanism is proposed for Na(+)-NQR, involving an electroneutral Na(+)/electron symport. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
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