1
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Sailer J, Nagel J, Akdogan B, Jauch AT, Engler J, Knolle PA, Zischka H. Deadly excess copper. Redox Biol 2024; 75:103256. [PMID: 38959622 PMCID: PMC11269798 DOI: 10.1016/j.redox.2024.103256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 06/13/2024] [Accepted: 06/23/2024] [Indexed: 07/05/2024] Open
Abstract
Higher eukaryotes' life is impossible without copper redox activity and, literally, every breath we take biochemically demonstrates this. However, this dependence comes at a considerable price to ensure target-oriented copper action. Thereto its uptake, distribution but also excretion are executed by specialized proteins with high affinity for the transition metal. Consequently, malfunction of copper enzymes/transporters, as is the case in hereditary Wilson disease that affects the intracellular copper transporter ATP7B, comes with serious cellular damage. One hallmark of this disease is the progressive copper accumulation, primarily in liver but also brain that becomes deadly if left untreated. Such excess copper toxicity may also result from accidental ingestion or attempted suicide. Recent research has shed new light into the cell-toxic mechanisms and primarily affected intracellular targets and processes of such excess copper that may even be exploited with respect to cancer therapy. Moreover, new therapies are currently under development to fight against deadly toxic copper.
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Affiliation(s)
- Judith Sailer
- Institute of Toxicology and Environmental Hygiene, Technical University Munich, School of Medicine and Health, Munich, Germany
| | - Judith Nagel
- Institute of Toxicology and Environmental Hygiene, Technical University Munich, School of Medicine and Health, Munich, Germany
| | - Banu Akdogan
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Adrian T Jauch
- Institute of Toxicology and Environmental Hygiene, Technical University Munich, School of Medicine and Health, Munich, Germany
| | - Jonas Engler
- Institute of Toxicology and Environmental Hygiene, Technical University Munich, School of Medicine and Health, Munich, Germany
| | - Percy A Knolle
- Institute of Molecular Immunology and Experimental Oncology, Technical University Munich, School of Medicine and Health, Munich, Germany
| | - Hans Zischka
- Institute of Toxicology and Environmental Hygiene, Technical University Munich, School of Medicine and Health, Munich, Germany; Institute of Molecular Toxicology and Pharmacology, Helmholtz Munich, German Research Center for Environmental Health, Neuherberg, Germany.
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2
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Peng P, DiSpirito AA, Lewis BJ, Nott JD, Semrau JD. Heterologous Biosynthesis of Methanobactin from Methylocystis sp. Strain SB2 in Methylosinus trichosporium OB3b. ACS Synth Biol 2024; 13:2347-2356. [PMID: 39109930 DOI: 10.1021/acssynbio.4c00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Aerobic methanotrophs, or methane-consuming microbes, are strongly dependent on copper for their activity. To satisfy this requirement, some methanotrophs produce a copper-binding compound, or chalkophore, called methanobactin (MB). In addition to playing a critical role in methanotrophy, MB has also been shown to have great promise in treating copper-related human diseases, perhaps most significantly Wilson's disease. In this congenital disorder, copper builds up in the liver, leading to irreversible damage and, in severe cases, complete organ failure. Remarkably, MB has been shown to reverse such damage in animal models, and there is a great deal of interest in upscaling MB production for expanded clinical trials. Such efforts, however, are currently hampered as (1) the natural rate of MB production rate by methanotrophs is low, (2) the use of methane as a substrate for MB production is problematic as it is explosive in air, (3) there is limited understanding of the entire pathway of MB biosynthesis, and (4) the most attractive form of MB is produced by Methylocystis sp. strain SB2, a methanotroph that is genetically intractable. Herein, we report heterologous biosynthesis of MB from Methylocystis sp. strain SB2 in an alternative methanotroph, Methylosinus trichosporium OB3b, not only on methane but also on methanol. As a result, the strategy described herein not only facilitates enhanced MB production but also provides opportunities to construct various mutants to delineate the entire pathway of MB biosynthesis, as well as the creation of modified forms of MB that may have enhanced therapeutic value.
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Affiliation(s)
- Peng Peng
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109-2125, United States
| | - Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011-3260, United States
| | - Braden J Lewis
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011-3260, United States
| | - Joel D Nott
- Office of Biotechnology Protein Facility, Iowa State University, Ames, Iowa 50011-3260, United States
| | - Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109-2125, United States
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3
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Manley OM, Shriver TJ, Xu T, Melendrez IA, Palacios P, Robson SA, Guo Y, Kelleher NL, Ziarek JJ, Rosenzweig AC. A multi-iron enzyme installs copper-binding oxazolone/thioamide pairs on a nontypeable Haemophilus influenzae virulence factor. Proc Natl Acad Sci U S A 2024; 121:e2408092121. [PMID: 38968106 PMCID: PMC11252979 DOI: 10.1073/pnas.2408092121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 06/01/2024] [Indexed: 07/07/2024] Open
Abstract
The multinuclear nonheme iron-dependent oxidases (MNIOs) are a rapidly growing family of enzymes involved in the biosynthesis of ribosomally synthesized, posttranslationally modified peptide natural products (RiPPs). Recently, a secreted virulence factor from nontypeable Haemophilus influenzae (NTHi) was found to be expressed from an operon, which we designate the hvf operon, that also encodes an MNIO. Here, we show by Mössbauer spectroscopy that the MNIO HvfB contains a triiron cofactor. We demonstrate that HvfB works together with HvfC [a RiPP recognition element (RRE)-containing partner protein] to perform six posttranslational modifications of cysteine residues on the virulence factor precursor peptide HvfA. Structural characterization by tandem mass spectrometry and NMR shows that these six cysteine residues are converted to oxazolone and thioamide pairs, similar to those found in the RiPP methanobactin. Like methanobactin, the mature virulence factor, which we name oxazolin, uses these modified residues to coordinate Cu(I) ions. Considering the necessity of oxazolin for host cell invasion by NTHi, these findings point to a key role for copper during NTHi infection. Furthermore, oxazolin and its biosynthetic pathway represent a potential therapeutic target for NTHi.
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Affiliation(s)
- Olivia M. Manley
- Department of Molecular Biosciences, Northwestern University, Evanston, IL60208
- Department of Chemistry, Northwestern University, Evanston, IL60208
| | - Tucker J. Shriver
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Tian Xu
- Department of Molecular Biosciences, Northwestern University, Evanston, IL60208
- Department of Chemistry, Northwestern University, Evanston, IL60208
| | - Isaac A. Melendrez
- Department of Molecular Biosciences, Northwestern University, Evanston, IL60208
- Department of Chemistry, Northwestern University, Evanston, IL60208
| | - Philip Palacios
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA15213
| | - Scott A. Robson
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA15213
| | - Neil L. Kelleher
- Department of Molecular Biosciences, Northwestern University, Evanston, IL60208
- Department of Chemistry, Northwestern University, Evanston, IL60208
| | - Joshua J. Ziarek
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL60611
| | - Amy C. Rosenzweig
- Department of Molecular Biosciences, Northwestern University, Evanston, IL60208
- Department of Chemistry, Northwestern University, Evanston, IL60208
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4
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Matsuda K, Maruyama H, Imachi K, Ikeda H, Wakimoto T. Actinobacterial chalkophores: the biosynthesis of hazimycins. J Antibiot (Tokyo) 2024; 77:228-237. [PMID: 38378905 DOI: 10.1038/s41429-024-00706-6] [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: 07/29/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 02/22/2024]
Abstract
Copper is a transition metal element with significant effects on the morphological development and secondary metabolism of actinobacteria. In some microorganisms, copper-binding natural products are employed to modulate copper homeostasis, although their significance in actinobacteria remains largely unknown. Here, we identified the biosynthetic genes of the diisocyanide natural product hazimycin in Kitasatospora purpeofusca HV058, through gene knock-out and heterologous expression. Biochemical analyses revealed that hazimycin A specifically binds to copper, which diminishes its antimicrobial activity. The presence of a set of putative importer/exporter genes surrounding the biosynthetic genes suggested that hazimycin is a chalkophore that modulates the intracellular copper level. A bioinformatic survey of homologous gene cassettes, as well as the identification of two previously unknown hazimycin-producing Streptomyces strains, indicated that the isocyanide-based mechanism of copper homeostasis is prevalent in actinobacteria.
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Affiliation(s)
- Kenichi Matsuda
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12, Nishi 6, Kita-ku, Sapporo, 060-0812, Japan.
| | - Hiroto Maruyama
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12, Nishi 6, Kita-ku, Sapporo, 060-0812, Japan
| | - Kumiko Imachi
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12, Nishi 6, Kita-ku, Sapporo, 060-0812, Japan
| | - Haruo Ikeda
- Technology Research Association for Next generation natural products chemistry, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Toshiyuki Wakimoto
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12, Nishi 6, Kita-ku, Sapporo, 060-0812, Japan.
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5
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Arnone V, Santana-Casiano JM, González-Dávila M, Sarthou G, Krisch S, Lodeiro P, Achterberg EP, González AG. Distribution of copper-binding ligands in Fram Strait and influences from the Greenland Shelf (GEOTRACES GN05). THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 909:168162. [PMID: 37952666 DOI: 10.1016/j.scitotenv.2023.168162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 09/11/2023] [Accepted: 10/25/2023] [Indexed: 11/14/2023]
Abstract
The Fram Strait represents the major gateway of Arctic Ocean waters towards the Nordic Seas and North Atlantic Ocean and is a key region to study the impact of climate change on biogeochemical cycles. In the region, information about trace metal speciation, such as copper, is scarce. This manuscript presents the concentrations and conditional stability constants of copper-binding ligands (LCu and log KcondCu2+L) in the water column of Fram Strait and the Greenland shelf (GEOTRACES cruise GN05). Cu-binding ligands were analysed by Competitive Ligand Exchange-Adsorptive Cathodic Stripping Voltammetry (CLE-ACSV) using salicylaldoxime (SA) as competitive ligand. Based on water masses and the hydrodynamic influences, three provinces were considered (coast, shelf, and Fram Strait) and differences were observed between regions and water masses. The strongest variability was observed in surface waters, with increasing LCu concentrations (mean values: Fram Strait = 2.6 ± 1.0 nM; shelf = 5.2 ± 1.3 nM; coast = 6.4 ± 0.8 nM) and decreasing log KcondCu2+L values (mean values: Fram Strait = 15.7 ± 0.3; shelf = 15.2 ± 0.3; coast = 14.8 ± 0.3) towards the west. The surface LCu concentrations obtained above the Greenland shelf indicate a supply from the coastal environment to the Polar Surface Water (PSW) which is an addition to the ligand exported from the central Arctic to Fram Strait. The significant differences (in terms of LCu and log KcondCu2+L) between shelf and coastal samples were explained considering the processes which modify ligand concentrations and binding strengths, such as biological activity in sea-ice, phytoplankton bloom in surface waters, bacterial degradation, and meltwater discharge from 79NG glacier terminus. Overall, the ligand concentration exceeded those of dissolved Cu (dCu) and kept the free copper (Cu2+) concentrations at femtomolar levels (0.13-21.13 fM). This indicates that Cu2+ toxicity limits were not reached and dCu levels were stabilized in surface waters by organic complexes, which favoured its transport to the Nordic Seas and North Atlantic Ocean and the development of microorganism.
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Affiliation(s)
- Veronica Arnone
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Spain
| | | | - Melchor González-Dávila
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Spain
| | | | - Stephan Krisch
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany
| | - Pablo Lodeiro
- Department of Chemistry, Physics, Environmental and Soil sciences, University of Lleida-AGROTECNIO-CERCA Center, Rovira Roure 191, 25198, Lleida, Spain
| | - Eric P Achterberg
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany
| | - Aridane G González
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Spain.
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6
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Peng W, Wang Z, Zhang Q, Yan S, Wang B. Unraveling the Valence State and Reactivity of Copper Centers in Membrane-Bound Particulate Methane Monooxygenase. J Am Chem Soc 2023; 145:25304-25317. [PMID: 37955571 DOI: 10.1021/jacs.3c08834] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Particulate methane monooxygenase (pMMO) plays a critical role in catalyzing the conversion of methane to methanol, constituting the initial step in the C1 metabolic pathway within methanotrophic bacteria. However, the membrane-bound pMMO's structure and catalytic mechanism, notably the copper's valence state and genuine active site for methane oxidation, have remained elusive. Based on the recently characterized structure of membrane-bound pMMO, extensive computational studies were conducted to address these long-standing issues. A comprehensive analysis comparing the quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulated structures with cryo-EM data indicates that both the CuC and CuD sites tend to stay in the Cu(I) valence state within the membrane environment. Additionally, the concurrent presence of Cu(I) at both CuC and CuD sites leads to the significant reduction of the ligand-binding cavity situated between them, making it less likely to accommodate a reductant molecule such as durohydroquinone (DQH2). Subsequent QM/MM calculations reveal that the CuD(I) site is more reactive than the CuC(I) site in oxygen activation, en route to H2O2 formation and the generation of Cu(II)-O•- species. Finally, our simulations demonstrate that the natural reductant ubiquinol (CoQH2) assumes a productive binding conformation at the CuD(I) site but not at the CuC(I) site. This provides evidence that the true active site of membrane-bound pMMOs may be CuD rather than CuC. These findings clarify pMMO's catalytic mechanism and emphasize the membrane environment's pivotal role in modulating the coordination structure and the activity of copper centers within pMMO.
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Affiliation(s)
- Wei Peng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, P. R. China
- Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, P. R. China
| | - Zikuan Wang
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany
| | - Qiaoyu Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, P. R. China
| | - Shengheng Yan
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, P. R. China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering and Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, P. R. China
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7
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Cupioli E, Gaigne FJM, Sachse A, Buday P, Weigand W, Liebing P, Arndt HD. Templated Total Synthesis of Cu(I)-Methanobactin OB3b. Angew Chem Int Ed Engl 2023; 62:e202304901. [PMID: 37403384 DOI: 10.1002/anie.202304901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/01/2023] [Accepted: 07/04/2023] [Indexed: 07/06/2023]
Abstract
Methanobactin OB3b (Mbn-OB3b) is a unique natural product with stunning affinity for copper ions (Ka ≈Cu(I) 1034 ). Here, we report the first total synthesis of Cu(I)-bound methanobactin OB3b featuring as key transformations a cyclodehydration-thioacylation sequence, to generate the conjugated heterocyclic systems, and a copper-templated cyclization, to complete the caged structure of the very sensitive target compound.
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Affiliation(s)
- Emilia Cupioli
- Friedrich-Schiller-Universität, Institut für Organische Chemie und Makromolekulare Chemie, Humboldtstr. 10, 07743, Jena, Germany
| | - Frédéric J M Gaigne
- Friedrich-Schiller-Universität, Institut für Organische Chemie und Makromolekulare Chemie, Humboldtstr. 10, 07743, Jena, Germany
| | - Anna Sachse
- Friedrich-Schiller-Universität, Institut für Organische Chemie und Makromolekulare Chemie, Humboldtstr. 10, 07743, Jena, Germany
| | - Philipp Buday
- Friedrich-Schiller-Universität, Institut für Anorganische und Analytische Chemie, Humboldtstr. 8, 07743, Jena, Germany
| | - Wolfgang Weigand
- Friedrich-Schiller-Universität, Institut für Anorganische und Analytische Chemie, Humboldtstr. 8, 07743, Jena, Germany
| | - Phil Liebing
- Friedrich-Schiller-Universität, Institut für Anorganische und Analytische Chemie, Humboldtstr. 8, 07743, Jena, Germany
| | - Hans-Dieter Arndt
- Friedrich-Schiller-Universität, Institut für Organische Chemie und Makromolekulare Chemie, Humboldtstr. 10, 07743, Jena, Germany
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8
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Qiu L, Lok KS, Lu Q, Zhong H, Guo X, Shim H. Zinc and copper supplements enhance trichloroethylene removal by Pseudomonas plecoglossicida in water. ENVIRONMENTAL TECHNOLOGY 2023; 44:3698-3709. [PMID: 35451932 DOI: 10.1080/09593330.2022.2069518] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
The effects of two microelements, zinc and copper, on the aerobic co-metabolic removal of trichloroethylene (10 mg/L) by the isolate Pseudomonas plecoglossicida were investigated. The strain was previously isolated from a petroleum-contaminated site using toluene (150 mg/L) as substrate. Different concentrations (1, 10 and 100 mg/L) of microelements provided with SO42- and Cl- were tested. The results showed the supplement of Zn2+ and Cu2+ at the low concentration (1 mg/L) significantly enhanced cell growth. The removal efficiencies for toluene and trichloroethylene were also enhanced at the low concentration (1 mg/L) of Zn2+ and Cu2+. Compared to the control without zinc supplement, higher concentrations of zinc (10 and 100 mg/L) enhanced the removal efficiencies for both toluene and trichloroethylene in the first three days but showed some inhibitory effect afterward. However, the higher concentrations of Cu2+ (10 and 100 mg/L) always showed inhibitory to the toluene removal while showing inhibitory to the TCE removal after three days. For both Zn2+ and Cu2+, the anions SO42- and Cl- did not show significant difference in their effects on the toluene removal. A possible mechanism for Zn2+ and Cu2+ to enhance the removal of toluene and trichloroethylene would be their involvement in toluene oxygenase-based transformation processes. In addition, high concentrations of Zn2+ and Cu2+ ions could be removed from the liquid by the cells accordingly. The results imply a potential of supplementing low concentrations of zinc and copper to enhance bioremediation of the sites co-contaminated with toluene and trichloroethylene.
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Affiliation(s)
- Lan Qiu
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, People's Republic of China
| | - Keng Seng Lok
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, People's Republic of China
| | - Qihong Lu
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, People's Republic of China
| | - Hua Zhong
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, People's Republic of China
| | - Xiaoyuan Guo
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, People's Republic of China
| | - Hojae Shim
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, People's Republic of China
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9
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Hwang Y, Na JG, Lee SJ. Transcriptional regulation of soluble methane monooxygenase via enhancer-binding protein derived from Methylosinus sporium 5. Appl Environ Microbiol 2023; 89:e0210422. [PMID: 37668365 PMCID: PMC10537576 DOI: 10.1128/aem.02104-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/07/2023] [Indexed: 09/06/2023] Open
Abstract
Methane is a major greenhouse gas, and methanotrophs regulate the methane level in the carbon cycle. Soluble methane monooxygenase (sMMO) is expressed in various methanotroph genera, including Alphaproteobacteria and Gammaproteobacteria, and catalyzes the hydroxylation of methane to methanol. It has been proposed that MmoR regulates the expression of sMMO as an enhancer-binding protein under copper-limited conditions; however, details on this transcriptional regulation remain limited. Herein, we elucidate the transcriptional pathway of sMMO depending on copper ion concentration, which affects the interaction of MmoR and sigma factor. MmoR and sigma-54 (σ54) from Methylosinus sporium 5 were successfully overexpressed in Escherichia coli and purified to investigate sMMO transcription in methanotrophs. The results indicated that σ54 binds to a promoter positioned -24 (GG) and -12 (TGC) upstream between mmoG and mmoX1. The binding affinity and selectivity are lower (Kd = 184.6 ± 6.2 nM) than those of MmoR. MmoR interacts with the upstream activator sequence (UAS) with a strong binding affinity (Kd = 12.5 ± 0.5 nM). Mutational studies demonstrated that MmoR has high selectivity to its binding partner (ACA-xx-TGT). Titration assays have demonstrated that MmoR does not coordinate with copper ions directly; however, its binding affinity to UAS decreases in a low-copper-containing medium. MmoR strongly interacts with adenosine triphosphate (Kd = 62.8 ± 0.5 nM) to generate RNA polymerase complex. This study demonstrated that the binding events of both MmoR and σ54 that regulate transcription in M. sporium 5 depend on the copper ion concentration. IMPORTANCE This study provides biochemical evidence of transcriptional regulation of soluble methane monooxygenase (sMMO) in methanotrophs that control methane levels in ecological systems. Previous studies have proposed transcriptional regulation of MMOs, including sMMO and pMMO, while we provide further evidence to elucidate its mechanism using a purified enhancer-binding protein (MmoR) and transcription factor (σ54). The characterization studies of σ54 and MmoR identified the promoter binding sites and enhancer-binding sequences essential for sMMO expression. Our findings also demonstrate that MmoR functions as a trigger for sMMO expression due to the high specificity and selectivity for enhancer-binding sequences. The UV-visible spectrum of purified MmoR suggested an iron coordination like other GAF domain, and that ATP is essential for the initiation of enhancer elements. Binding assays indicated that these interactions are blocked by the copper ion. These results provide novel insights into gene regulation of methanotrophs.
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Affiliation(s)
- Yunha Hwang
- Department of Chemistry, Jeonbuk National University , Jeonju, South Korea
| | - Jeong-Geol Na
- Department of Chemical Engineering, Sogang University , Seoul, South Korea
| | - Seung Jae Lee
- Department of Chemistry, Jeonbuk National University , Jeonju, South Korea
- Institute of Molecular Biology and Genetics, Jeonbuk National University , Jeonju, South Korea
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10
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Ongpipattanakul C, Desormeaux EK, DiCaprio A, van der Donk WA, Mitchell DA, Nair SK. Mechanism of Action of Ribosomally Synthesized and Post-Translationally Modified Peptides. Chem Rev 2022; 122:14722-14814. [PMID: 36049139 PMCID: PMC9897510 DOI: 10.1021/acs.chemrev.2c00210] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a natural product class that has undergone significant expansion due to the rapid growth in genome sequencing data and recognition that they are made by biosynthetic pathways that share many characteristic features. Their mode of actions cover a wide range of biological processes and include binding to membranes, receptors, enzymes, lipids, RNA, and metals as well as use as cofactors and signaling molecules. This review covers the currently known modes of action (MOA) of RiPPs. In turn, the mechanisms by which these molecules interact with their natural targets provide a rich set of molecular paradigms that can be used for the design or evolution of new or improved activities given the relative ease of engineering RiPPs. In this review, coverage is limited to RiPPs originating from bacteria.
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Affiliation(s)
- Chayanid Ongpipattanakul
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Emily K. Desormeaux
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Adam DiCaprio
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Wilfred A. van der Donk
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
| | - Douglas A. Mitchell
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
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11
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Multiple Mechanisms for Copper Uptake by Methylosinus trichosporium OB3b in the Presence of Heterologous Methanobactin. mBio 2022; 13:e0223922. [PMID: 36129259 PMCID: PMC9601215 DOI: 10.1128/mbio.02239-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methanotrophs require copper for their activity as it plays a critical role in the oxidation of methane to methanol. To sequester copper, some methanotrophs secrete a copper-binding compound termed methanobactin (MB). MB, after binding copper, is reinternalized via a specific outer membrane TonB-dependent transporter (TBDT). Methylosinus trichosporium OB3b has two such TBDTs (MbnT1 and MbnT2) that enable M. trichosporium OB3b to take up not only its own MB (MB-OB3b) but also heterologous MB produced from other methanotrophs, e.g., MB of Methylocystis sp. strain SB2 (MB-SB2). Here, we show that uptake of copper in the presence of heterologous MB-SB2 can either be achieved by initiating transcription of mbnT2 or by using its own MB-OB3b to extract copper from MB-SB2. Transcription of mbnT2 is mediated by the N-terminal signaling domain of MbnT2 together with an extracytoplasmic function sigma factor and an anti-sigma factor encoded by mbnI2 and mbnR2, respectively. Deletion of mbnI2R2 or excision of the N-terminal region of MbnT2 abolished induction of mbnT2. However, copper uptake from MB-SB2 was still observed in M. trichosporium OB3b mutants that were defective in MbnT2 induction/function, suggesting another mechanism for uptake copper-loaded MB-SB2. Additional deletion of MB-OB3b synthesis genes in the M. trichosporium OB3b mutants defective in MbnT2 induction/function disrupted their ability to take up copper in the presence of MB-SB2, indicating a role of MB-OB3b in copper extraction from MB-SB2.
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12
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Rushworth DD, Christl I, Kumar N, Hoffmann K, Kretzschmar R, Lehmann MF, Schenkeveld WDC, Kraemer SM. Copper mobilisation from Cu sulphide minerals by methanobactin: Effect of pH, oxygen and natural organic matter. GEOBIOLOGY 2022; 20:690-706. [PMID: 35716154 PMCID: PMC9544142 DOI: 10.1111/gbi.12505] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 05/03/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Aerobic methane oxidation (MOx) depends critically on the availability of copper (Cu) as a crucial component of the metal centre of particulate methane monooxygenase, one of the main enzymes involved in MOx. Some methanotrophs have developed Cu acquisition strategies, in which they exude Cu-binding ligands termed chalkophores under conditions of low Cu availability. A well-characterised chalkophore is methanobactin (mb), exuded by the microaerophilic methanotroph Methylosinus trichosporium OB3b. Aerobic methanotrophs generally reside close to environmental oxic-anoxic interfaces, where the formation of Cu sulphide phases can aggravate the limitation of bioavailable Cu due to their low solubility. The reactivity of chalkophores towards such Cu sulphide mineral phases has not yet been investigated. In this study, a combination of dissolution experiments and equilibrium modelling was used to examine the dissolution and solubility of bulk and nanoparticulate Cu sulphide minerals in the presence of mb as influenced by pH, oxygen and natural organic matter. In general, we show that mb is effective at increasing the dissolved Cu concentrations in the presence of a variety of Cu sulphide phases that may potentially limit Cu bioavailability. More Cu was mobilised per mole of mb from Cu sulphide nanoparticles compared with well-crystalline bulk covellite (CuS). In general, the efficacy of mb at mobilising Cu from Cu sulphides is pH-dependent. At lower pH, e.g. pH 5, mb was ineffective at solubilizing Cu. The presence of mb increased dissolved Cu concentrations between pH 7 and 8.5, where the solubility of all Cu sulphides is generally low, both in the presence and absence of oxygen. These results suggest that chalkophore-promoted Cu mobilisation from sulphide phases is an effective extracellular mechanism for increasing dissolved Cu concentrations at oxic-anoxic interfaces, particularly in the neutral to slightly alkaline pH range. This suggests that aerobic methanotrophs may be able to fulfil their Cu requirements via the exudation of mb in natural environments where the bioavailability of Cu is constrained by very stable Cu sulphide phases.
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Affiliation(s)
- Danielle D. Rushworth
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaViennaAustria
| | - Iso Christl
- Soil ChemistryInstitute of Biogeochemistry and Pollutant Dynamics, ETHZurichSwitzerland
| | - Naresh Kumar
- Soil Chemistry and Chemical Soil Quality, Environmental SciencesWageningen UniversityWageningenThe Netherlands
| | - Kevin Hoffmann
- Soil ChemistryInstitute of Biogeochemistry and Pollutant Dynamics, ETHZurichSwitzerland
| | - Ruben Kretzschmar
- Soil ChemistryInstitute of Biogeochemistry and Pollutant Dynamics, ETHZurichSwitzerland
| | - Moritz F. Lehmann
- Department of Environmental GeosciencesUniversity of BaselBaselSwitzerland
| | - Walter D. C. Schenkeveld
- Soil Chemistry and Chemical Soil Quality, Environmental SciencesWageningen UniversityWageningenThe Netherlands
| | - Stephan M. Kraemer
- Centre for Microbiology and Environmental Systems ScienceUniversity of ViennaViennaAustria
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13
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Jia-Ying X, Xue-Chun L, Li-Rui S, Jia-Yu Z, Chun-Gu X. Simple and rapid detection of calcium peroxide in flour based on methanobactin peroxidase-like activity. Food Chem 2022; 378:132041. [PMID: 35042104 DOI: 10.1016/j.foodchem.2022.132041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/18/2021] [Accepted: 01/01/2022] [Indexed: 11/26/2022]
Abstract
Calcium peroxide is forbidden to be added to flour as brightener in many countries. A rapid and sensitive spectrophotometric method for the detection of calcium peroxide in flour was proposed. Methanobactin (Mb), a copper-binding small peptide of methanotrophs with excellent peroxidase-like activity, has been successfully applied for H2O2-mediated co-oxidation between phenol and 4-aminoantipyrine to give a colored product that can be detected at 505 nm. When the concentration of Mb-Cu was 6.5 × 10-6 mol/L, the detection temperature was 50 ℃, and the detection time was 5 min, the linear range for quantification of calcium peroxide concentration was observed between 0.4 and 10.0 mg/L with R2 = 0.99397. The limit of detection was 0.027 mg/L (3.34 mg/kg flour) and the average recovery of standard addition was 99.6%-100.5%. Mb was very stable and still maintained catalytic activity even at 50 ℃ in acidic medium, which gave the proposed method has simple process and rapid detection speed.
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Affiliation(s)
- Xin Jia-Ying
- Harbin University of Commerce, Key Laboratory of Food Science and Engineering, Harbin 150076, People's Republic of China; State Key Laboratory of Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China.
| | - Lu Xue-Chun
- Harbin University of Commerce, Key Laboratory of Food Science and Engineering, Harbin 150076, People's Republic of China
| | - Sun Li-Rui
- Harbin University of Commerce, Key Laboratory of Food Science and Engineering, Harbin 150076, People's Republic of China
| | - Zhang Jia-Yu
- Harbin University of Commerce, Key Laboratory of Food Science and Engineering, Harbin 150076, People's Republic of China
| | - Xia Chun-Gu
- State Key Laboratory of Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China
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14
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Roskova Z, Skarohlid R, McGachy L. Siderophores: an alternative bioremediation strategy? THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 819:153144. [PMID: 35038542 DOI: 10.1016/j.scitotenv.2022.153144] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 05/15/2023]
Abstract
Siderophores are small molecular weight iron scavengers that are mainly produced by bacteria, fungi, and plants. Recently, they have attracted increasing attention because of their potential role in environmental bioremediation. Although siderophores are generally considered to exhibit high specificity for iron, they have also been reported to bind to various metal and metalloid ions. This unique ability allows siderophores to solubilise and mobilise heavy metals and metalloids from soil, thereby facilitating their bioremediation. In addition, because of their redox nature, they can mediate the production of reactive oxygen species (ROS), and thus promote the biodegradation of organic contaminants. The aim of this review is to summarise the existing knowledge on the developed strategies of siderophore-assisted bioremediation of metals, metalloids, and organic contaminants. Additionally, this review also includes the biosynthesis and classification of microbial and plant siderophores.
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Affiliation(s)
- Zuzana Roskova
- Department of Environmental Chemistry, University of Chemistry and Technology Prague, Technická 5, 16628 Prague, Czech Republic
| | - Radek Skarohlid
- Department of Environmental Chemistry, University of Chemistry and Technology Prague, Technická 5, 16628 Prague, Czech Republic
| | - Lenka McGachy
- Department of Environmental Chemistry, University of Chemistry and Technology Prague, Technická 5, 16628 Prague, Czech Republic.
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15
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Cu2+ induced Regulation and construction of FAD-Mb/Cu-Mb@AuNPs Bi-functional mimetic enzyme and application in glucose visualization detection. Microchem J 2022. [DOI: 10.1016/j.microc.2022.107207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Liu H, Ding S, Lu Q, Jian Y, Wei G, Yuan Z. a Versatile Schiff Base Chemosensor for the Determination of Trace Co 2+, Ni 2+, Cu 2+, and Zn 2+ in the Water and Its Bioimaging Applications. ACS OMEGA 2022; 7:7585-7594. [PMID: 35284732 PMCID: PMC8908528 DOI: 10.1021/acsomega.1c05960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
In this work, a simple and versatile Schiff base chemosensor (L) was developed for the detection of four adjacent row 4 metal ions (Co2+, Ni2+, Cu2+, and Zn2+) through colorimetric or fluorescent analyses. L could recognize the target ions in solutions containing a wide range of other cations and anions. The recognition mechanisms were verified with a Job's plot, HR-MS assays, and 1H NMR titration experiments. Then, L was employed to develop colorimetric test strips and TLC plates for Co2+. Meanwhile, L was capable of quantitatively measuring the amount of target ions in tap water and river water samples. Notably, L was used for imaging Zn2+ in HepG2 cells, zebrafish, and tumor-bearing mice, which demonstrated its potential biological applications. Therefore, L can probably serve as a versatile tool for the detection of the target metal ions in environmental and biological applications.
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Affiliation(s)
- Hongmei Liu
- Key
Laboratory of Basic Pharmacology of Ministry of Education and Joint
International Research Laboratory of Ethnomedicine of Ministry of
Education, Zunyi, Guizhou Province 563000, China
- School
of Pharmacy, Zunyi Medical University, Zunyi, Guizhou Province 563000, China
- Guizhou
International Scientific and Technological Cooperation Base for Medical
Photo-Theranostics Technology and Innovative Drug Development, Zunyi, Guizhou Province 563000, China
- Key
Laboratory of Biocatalysis and Chiral Drug Synthesis of Guizhou Province, Zunyi, Guizhou Province 563000, China
- Generic
Drug Research Center of Guizhou Province, Zunyi, Guizhou Province 563000, China
| | - Shangli Ding
- Key
Laboratory of Basic Pharmacology of Ministry of Education and Joint
International Research Laboratory of Ethnomedicine of Ministry of
Education, Zunyi, Guizhou Province 563000, China
- School
of Pharmacy, Zunyi Medical University, Zunyi, Guizhou Province 563000, China
- Guizhou
International Scientific and Technological Cooperation Base for Medical
Photo-Theranostics Technology and Innovative Drug Development, Zunyi, Guizhou Province 563000, China
- Key
Laboratory of Biocatalysis and Chiral Drug Synthesis of Guizhou Province, Zunyi, Guizhou Province 563000, China
- Generic
Drug Research Center of Guizhou Province, Zunyi, Guizhou Province 563000, China
| | - Quan Lu
- Key
Laboratory of Basic Pharmacology of Ministry of Education and Joint
International Research Laboratory of Ethnomedicine of Ministry of
Education, Zunyi, Guizhou Province 563000, China
- School
of Pharmacy, Zunyi Medical University, Zunyi, Guizhou Province 563000, China
- Guizhou
International Scientific and Technological Cooperation Base for Medical
Photo-Theranostics Technology and Innovative Drug Development, Zunyi, Guizhou Province 563000, China
- Key
Laboratory of Biocatalysis and Chiral Drug Synthesis of Guizhou Province, Zunyi, Guizhou Province 563000, China
- Generic
Drug Research Center of Guizhou Province, Zunyi, Guizhou Province 563000, China
| | - Yue Jian
- Key
Laboratory of Basic Pharmacology of Ministry of Education and Joint
International Research Laboratory of Ethnomedicine of Ministry of
Education, Zunyi, Guizhou Province 563000, China
- School
of Pharmacy, Zunyi Medical University, Zunyi, Guizhou Province 563000, China
- Guizhou
International Scientific and Technological Cooperation Base for Medical
Photo-Theranostics Technology and Innovative Drug Development, Zunyi, Guizhou Province 563000, China
- Key
Laboratory of Biocatalysis and Chiral Drug Synthesis of Guizhou Province, Zunyi, Guizhou Province 563000, China
- Generic
Drug Research Center of Guizhou Province, Zunyi, Guizhou Province 563000, China
| | - Gang Wei
- Commonwealth
Scientific and Industrial Research Organization Manufacturing, Lindfield, New South Wales 2070, Australia
| | - Zeli Yuan
- Key
Laboratory of Basic Pharmacology of Ministry of Education and Joint
International Research Laboratory of Ethnomedicine of Ministry of
Education, Zunyi, Guizhou Province 563000, China
- School
of Pharmacy, Zunyi Medical University, Zunyi, Guizhou Province 563000, China
- Guizhou
International Scientific and Technological Cooperation Base for Medical
Photo-Theranostics Technology and Innovative Drug Development, Zunyi, Guizhou Province 563000, China
- Key
Laboratory of Biocatalysis and Chiral Drug Synthesis of Guizhou Province, Zunyi, Guizhou Province 563000, China
- Generic
Drug Research Center of Guizhou Province, Zunyi, Guizhou Province 563000, China
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17
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Dou C, Long Z, Li S, Zhou D, Jin Y, Zhang L, Zhang X, Zheng Y, Li L, Zhu X, Liu Z, He S, Yan W, Yang L, Xiong J, Fu X, Qi S, Ren H, Chen S, Dai L, Wang B, Cheng W. Crystal structure and catalytic mechanism of the MbnBC holoenzyme required for methanobactin biosynthesis. Cell Res 2022; 32:302-314. [PMID: 35110668 PMCID: PMC8888699 DOI: 10.1038/s41422-022-00620-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/12/2022] [Indexed: 02/08/2023] Open
Abstract
Methanobactins (Mbns) are a family of copper-binding peptides involved in copper uptake by methanotrophs, and are potential therapeutic agents for treating diseases characterized by disordered copper accumulation. Mbns are produced via modification of MbnA precursor peptides at cysteine residues catalyzed by the core biosynthetic machinery containing MbnB, an iron-dependent enzyme, and MbnC. However, mechanistic details underlying the catalysis of the MbnBC holoenzyme remain unclear. Here, we present crystal structures of MbnABC complexes from two distinct species, revealing that the leader peptide of the substrate MbnA binds MbnC for recruitment of the MbnBC holoenzyme, while the core peptide of MbnA resides in the catalytic cavity created by the MbnB-MbnC interaction which harbors a unique tri-iron cluster. Ligation of the substrate sulfhydryl group to the tri-iron center achieves a dioxygen-dependent reaction for oxazolone-thioamide installation. Structural analysis of the MbnABC complexes together with functional investigation of MbnB variants identified a conserved catalytic aspartate residue as a general base required for MbnBC-mediated MbnA modification. Together, our study reveals the similar architecture and function of MbnBC complexes from different species, demonstrating an evolutionarily conserved catalytic mechanism of the MbnBC holoenzymes.
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Affiliation(s)
- Chao Dou
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Zhaolin Long
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Shoujie Li
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Dan Zhou
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Ying Jin
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Li Zhang
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Xuan Zhang
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, China
| | - Yanhui Zheng
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Lin Li
- National Institute of Biological Sciences, NIBS, Beijing, China
| | - Xiaofeng Zhu
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China.,College of Life Science, Sichuan University, Chengdu, Sichuan, China
| | - Zheng Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing Key Laboratory for Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Siyu He
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Weizhu Yan
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Lulu Yang
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Jie Xiong
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Xianghui Fu
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Shiqian Qi
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Haiyan Ren
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - She Chen
- National Institute of Biological Sciences, NIBS, Beijing, China
| | - Lunzhi Dai
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Binju Wang
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, China
| | - Wei Cheng
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China.
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18
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MbnC is not required for the formation of the N-terminal oxazolone in the methanobactin from Methylosinus trichosporium OB3b. Appl Environ Microbiol 2021; 88:e0184121. [PMID: 34731053 PMCID: PMC8788703 DOI: 10.1128/aem.01841-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methanobactins (MBs) are ribosomally synthesized and post-translationally modified peptides (RiPPs) produced by methanotrophs for copper uptake. The post-translational modification that define MBs is the formation of two heterocyclic groups with associated thioamines from X-Cys dipeptide sequences. Both heterocyclic groups in the MB from Methylosinus trichosporium OB3b (MB-OB3b) are oxazolone groups. The precursor gene for MB-OB3b, mbnA, which is part of a gene cluster that contains both annotated and unannotated genes. One of those unannotated genes, mbnC, is found in all MB operons, and in conjunction with mbnB, is reported to be involved in the formation of both heterocyclic groups in all MBs. To determine the function of mbnC, a deletion mutation was constructed in M. trichosporium OB3b, and the MB produced from the ΔmbnC mutant was purified and structurally characterized by UV-visible absorption spectroscopy, mass spectrometry and solution NMR spectroscopy. MB-OB3b from ΔmbnC was missing the C-terminal Met and also found to contain a Pro and a Cys in place of the pyrrolidiny-oxazolone-thioamide group. These results demonstrate MbnC is required for the formation of the C-terminal pyrrolidinyl-oxazolone-thioamide group from the Pro-Cys dipeptide, but not for the formation of the N-terminal 3-methylbutanol-oxazolone-thioamide group from the N-terminal dipeptide Leu-Cys. IMPORTANCE A number of environmental and medical applications have been proposed for MBs, including bioremediation of toxic metals, nanoparticle formation, as well as for the treatment of copper- and iron-related diseases. However, before MBs can be modified and optimized for any specific application, the biosynthetic pathway for MB production must be defined. The discovery that mbnC is involved in the formation of the C-terminal oxazolone group with associated thioamide but not for the formation of the N-terminal oxazolone group with associated thioamide in M. trichosporium OB3b suggests the enzymes responsible for post-translational modification(s) of the two oxazolone groups are not identical.
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19
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Two TonB-dependent transporters in Methylosinus trichosporium OB3b are responsible for uptake of different forms of methanobactin and are involved in the canonical 'copper switch'. Appl Environ Microbiol 2021; 88:e0179321. [PMID: 34669437 DOI: 10.1128/aem.01793-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Copper is an important component of methanotrophic physiology as it controls the expression and activity of alternative forms of methane monooxygenase (MMO). To collect copper, some methanotrophs secrete a chalkophore or copper-binding compound called methanobactin (MB). MB is a ribosomally synthesized post-translationally modified polypeptide (RiPP) that, after binding copper, is collected by MbnT, a TonB-dependent transporter (TBDT). Structurally different forms of MB have been characterized, and here we show that different forms of MB are collected by specific TBDTs. Further, we report that in the model methanotroph, Methylosinus trichosporium OB3b, expression of the TBDT required for uptake of a different MB made by Methylocystis sp. strain SB2 (MB-SB2), is induced in the presence of MB-SB2, suggesting that methanotrophs have developed specific machinery and regulatory systems to actively take up MB from other methanotrophs for copper collection. Moreover, the canonical "copper-switch" in Ms. trichosporium OB3b that controls expression of alternative MMOs is apparent if one of the two TBDTs required for MB-OB3b and MB-SB2 uptake is knocked out, but is disrupted if both TBDTs are knocked out. These data indicate that MB uptake, including the uptake of exogenous MB, plays an important role in the copper switch in M. trichosporium OB3b and thus overall activity. Based on these data, we propose a revised model for the "copper-switch" in this methanotroph that involves MB uptake. IMPORTANCE In this study, we demonstrate that different TonB-dependent transporters (TBDTs) in the model methanotroph Methylosinus trichosporium OB3b are responsible for uptake of either endogenous MB or exogenous MB. Interestingly, the presence of exogenous MB induces expression of its specific TBDT in M. trichosporium OB3b, suggesting that this methanotroph is able to actively take up MB produced by others. This work contributes to our understanding of how microbes collect and compete for copper, and also helps inform how such uptake coordinates the expression of different forms of methane monooxygenase. Such studies are likely to be very important to develop a better understanding of methanotrophic interactions via synthesis and secretion of secondary metabolites such as methanobactin and thus provide additional means whereby these microbes can be manipulated for a variety of environmental and industrial purposes.
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20
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Eckert P, Johs A, Semrau JD, DiSpirito AA, Richardson J, Sarangi R, Herndon E, Gu B, Pierce EM. Spectroscopic and computational investigations of organometallic complexation of group 12 transition metals by methanobactins from Methylocystis sp. SB2. J Inorg Biochem 2021; 223:111496. [PMID: 34271330 PMCID: PMC10569158 DOI: 10.1016/j.jinorgbio.2021.111496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/17/2021] [Accepted: 05/26/2021] [Indexed: 12/30/2022]
Abstract
Methanotrophic bacteria catalyze the aerobic oxidation of methane to methanol using Cu-containing enzymes, thereby exerting a modulating influence on the global methane cycle. To facilitate the acquisition of Cu ions, some methanotrophic bacteria secrete small modified peptides known as "methanobactins," which strongly bind Cu and function as an extracellular Cu recruitment relay, analogous to siderophores and Fe. In addition to Cu, methanobactins form complexes with other late transition metals, including the Group 12 transition metals Zn, Cd, and Hg, although the interplay among solution-phase configurations, metal interactions, and the spectroscopic signatures of methanobactin-metal complexes remains ambiguous. In this study, the complexation of Zn, Cd, and Hg by methanobactin from Methylocystis sp. strain SB2 was studied using a combination of absorbance, fluorescence, extended x-ray absorption fine structure (EXAFS) spectroscopy, and time-dependent density functional theory (TD-DFT) calculations. We report changes in sample absorbance and fluorescence spectral dynamics, which occur on a wide range of experimental timescales and characterize a clear stoichiometric complexation dependence. Mercury L3-edge EXAFS and TD-DFT calculations suggest a linear model for HgS coordination, and TD-DFT suggests a tetrahedral model for Zn2+ and Cd2+. We observed an enhancement in the fluorescence of methanobactin upon interaction with transition metals and propose a mechanism of complexation-hindered isomerization drawing inspiration from the wild-type Green Fluorescent Protein active site. Collectively, our results represent the first combined computational and experimental spectroscopy study of methanobactins and shed new light on molecular interactions and dynamics that characterize complexes of methanobactins with Group 12 transition metals.
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Affiliation(s)
- Peter Eckert
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - Alexander Johs
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Jeremy D Semrau
- Civil & Environmental Engineering, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Jocelyn Richardson
- Structural Molecular Biology Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94306, USA
| | - Ritimukta Sarangi
- Structural Molecular Biology Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94306, USA
| | - Elizabeth Herndon
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Baohua Gu
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Eric M Pierce
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
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21
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Fasae KD, Abolaji AO, Faloye TR, Odunsi AY, Oyetayo BO, Enya JI, Rotimi JA, Akinyemi RO, Whitworth AJ, Aschner M. Metallobiology and therapeutic chelation of biometals (copper, zinc and iron) in Alzheimer's disease: Limitations, and current and future perspectives. J Trace Elem Med Biol 2021; 67:126779. [PMID: 34034029 DOI: 10.1016/j.jtemb.2021.126779] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 04/03/2021] [Accepted: 05/10/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is the most prevalent cause of cognitive impairment and dementia worldwide. The pathobiology of the disease has been studied in the form of several hypotheses, ranging from oxidative stress, amyloid-beta (Aβ) aggregation, accumulation of tau forming neurofibrillary tangles (NFT) through metal dysregulation and homeostasis, dysfunction of the cholinergic system, and to inflammatory and autophagic mechanism. However, none of these hypotheses has led to confirmed diagnostics or approved cure for the disease. OBJECTIVE This review is aimed as a basic and an encyclopedic short course into metals in AD and discusses the advances in chelation strategies and developments adopted in the treatment of the disease. Since there is accumulating evidence of the role of both biometal dyshomeostasis (iron (Fe), copper (Cu), and zinc (Zn)) and metal-amyloid interactions that lead to the pathogenesis of AD, this review focuses on unraveling therapeutic chelation strategies that have been considered in the treatment of the disease, aiming to sequester free and protein-bound metal ions and reducing cerebral metal burden. Promising compounds possessing chemically modified moieties evolving as multi-target ligands used as anti-AD drug candidates are also covered. RESULTS AND CONCLUSION Several multidirectional and multifaceted studies on metal chelation therapeutics show the need for improved synthesis, screening, and analysis of compounds to be able to effectively present chelating anti-AD drugs. Most drug candidates studied have limitations in their physicochemical properties; some enhance redistribution of metal ions, while others indirectly activate signaling pathways in AD. The metal chelation process in vivo still needs to be established and the design of potential anti-AD compounds that bi-functionally sequester metal ions as well as inhibit the Aβ aggregation by competing with the metal ions and reducing metal-induced oxidative damage and neurotoxicity may signal a bright end in chelation-based therapeutics of AD.
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Affiliation(s)
- Kehinde D Fasae
- Department of Biochemistry, Molecular Drug Metabolism and Toxicology Unit, College of Medicine, University of Ibadan, Nigeria
| | - Amos O Abolaji
- Department of Biochemistry, Molecular Drug Metabolism and Toxicology Unit, College of Medicine, University of Ibadan, Nigeria.
| | - Tolulope R Faloye
- Department of Biochemistry, Molecular Drug Metabolism and Toxicology Unit, College of Medicine, University of Ibadan, Nigeria
| | - Atinuke Y Odunsi
- Department of Biochemistry, Molecular Drug Metabolism and Toxicology Unit, College of Medicine, University of Ibadan, Nigeria
| | - Bolaji O Oyetayo
- Department of Pharmacology and Therapeutics, Neuropharmacology Unit, College of Medicine, University of Ibadan, Nigeria
| | - Joseph I Enya
- Department of Anatomy, University of Ilorin, Kwara State, Nigeria
| | - Joshua A Rotimi
- Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Rufus O Akinyemi
- Neuroscience and Ageing Research Unit, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria
| | | | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA.
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22
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Karthikeyan OP, Smith TJ, Dandare SU, Parwin KS, Singh H, Loh HX, Cunningham MR, Williams PN, Nichol T, Subramanian A, Ramasamy K, Kumaresan D. Metal(loid) speciation and transformation by aerobic methanotrophs. MICROBIOME 2021; 9:156. [PMID: 34229757 PMCID: PMC8262016 DOI: 10.1186/s40168-021-01112-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/09/2021] [Indexed: 05/06/2023]
Abstract
Manufacturing and resource industries are the key drivers for economic growth with a huge environmental cost (e.g. discharge of industrial effluents and post-mining substrates). Pollutants from waste streams, either organic or inorganic (e.g. heavy metals), are prone to interact with their physical environment that not only affects the ecosystem health but also the livelihood of local communities. Unlike organic pollutants, heavy metals or trace metals (e.g. chromium, mercury) are non-biodegradable, bioaccumulate through food-web interactions and are likely to have a long-term impact on ecosystem health. Microorganisms provide varied ecosystem services including climate regulation, purification of groundwater, rehabilitation of contaminated sites by detoxifying pollutants. Recent studies have highlighted the potential of methanotrophs, a group of bacteria that can use methane as a sole carbon and energy source, to transform toxic metal (loids) such as chromium, mercury and selenium. In this review, we synthesise recent advances in the role of essential metals (e.g. copper) for methanotroph activity, uptake mechanisms alongside their potential to transform toxic heavy metal (loids). Case studies are presented on chromium, selenium and mercury pollution from the tanneries, coal burning and artisanal gold mining, respectively, which are particular problems in the developing economy that we propose may be suitable for remediation by methanotrophs. Video Abstract.
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Affiliation(s)
- Obulisamy Parthiba Karthikeyan
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
- Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI USA
- Department of Engineering Technology, College of Technology, University of Houston, Houston, TX USA
| | - Thomas J. Smith
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK
| | - Shamsudeen Umar Dandare
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
| | - Kamaludeen Sara Parwin
- Department of Environmental Sciences, Tamil Nadu Agricultural University, Coimbatore, India
| | - Heetasmin Singh
- Department of Chemistry, University of Guyana, Georgetown, Guyana
| | - Hui Xin Loh
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
| | - Mark R Cunningham
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
| | - Paul Nicholas Williams
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
| | - Tim Nichol
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK
| | | | | | - Deepak Kumaresan
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
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23
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Abstract
Methanobactins (MBs) are small (<1,300-Da) posttranslationally modified copper-binding peptides and represent the extracellular component of a copper acquisition system in some methanotrophs. Interestingly, MBs can bind a range of metal ions, with some being reduced after binding, e.g., Cu2+ reduced to Cu+. Other metal ions, however, are bound but not reduced, e.g., K+. The source of electrons for selective metal ion reduction has been speculated to be water but never empirically shown. Here, using H218O, we show that when MBs from Methylocystis sp. strain SB2 (MB-SB2) and Methylosinus trichosporium OB3b (MB-OB3) were incubated in the presence of either Au3+, Cu2, or Ag+, 18,18O2 and free protons were released. No 18,18O2 production was observed in the presence of either MB-SB2 or MB-OB3b alone, gold alone, copper alone, or silver alone or when K+ or Mo2+ was incubated with MB-SB2. In contrast to MB-OB3b, MB-SB2 binds Fe3+ with an N2S2 coordination and will also reduce Fe3+ to Fe2+. Iron reduction was also found to be coupled to the oxidation of 2H2O and the generation of O2. MB-SB2 will also couple Hg2+, Ni2+, and Co2+ reduction to the oxidation of 2H2O and the generation of O2, but MB-OB3b will not, ostensibly as MB-OB3b binds but does not reduce these metal ions. To determine if the O2 generated during metal ion reduction by MB could be coupled to methane oxidation, 13CH4 oxidation by Methylosinus trichosporium OB3b was monitored under anoxic conditions. The results demonstrate that O2 generation from metal ion reduction by MB-OB3b can support methane oxidation. IMPORTANCE The discovery that MB will couple the oxidation of H2O to metal ion reduction and the release of O2 suggests that methanotrophs expressing MB may be able to maintain their activity under hypoxic/anoxic conditions through the “self-generation” of dioxygen required for the initial oxidation of methane to methanol. Such an ability may be an important factor in enabling methanotrophs to not only colonize the oxic-anoxic interface where methane concentrations are highest but also tolerate significant temporal fluctuations of this interface. Given that genomic surveys often show evidence of aerobic methanotrophs within anoxic zones, the ability to express MB (and thereby generate dioxygen) may be an important parameter in facilitating their ability to remove methane, a potent greenhouse gas, before it enters the atmosphere.
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24
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Semrau JD, DiSpirito AA, Obulisamy PK, Kang-Yun CS. Methanobactin from methanotrophs: genetics, structure, function and potential applications. FEMS Microbiol Lett 2020; 367:5804726. [PMID: 32166327 DOI: 10.1093/femsle/fnaa045] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022] Open
Abstract
Aerobic methane-oxidizing bacteria of the Alphaproteobacteria have been found to express a novel ribosomally synthesized post-translationally modified polypeptide (RiPP) termed methanobactin (MB). The primary function of MB in these microbes appears to be for copper uptake, but MB has been shown to have multiple capabilities, including oxidase, superoxide dismutase and hydrogen peroxide reductase activities, the ability to detoxify mercury species, as well as acting as an antimicrobial agent. Herein, we describe the diversity of known MBs as well as the genetics underlying MB biosynthesis. We further propose based on bioinformatics analyses that some methanotrophs may produce novel forms of MB that have yet to be characterized. We also discuss recent findings documenting that MBs play an important role in controlling copper availability to the broader microbial community, and as a result can strongly affect the activity of microbes that require copper for important enzymatic transformations, e.g. conversion of nitrous oxide to dinitrogen. Finally, we describe procedures for the detection/purification of MB, as well as potential medical and industrial applications of this intriguing RiPP.
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Affiliation(s)
- Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA 48109-2125
| | - Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA 50011
| | | | - Christina S Kang-Yun
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA 48109-2125
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25
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Naizabekov S, Lee EY. Genome-Scale Metabolic Model Reconstruction and in Silico Investigations of Methane Metabolism in Methylosinus trichosporium OB3b. Microorganisms 2020; 8:microorganisms8030437. [PMID: 32244934 PMCID: PMC7144005 DOI: 10.3390/microorganisms8030437] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 01/09/2023] Open
Abstract
Methylosinus trichosporium OB3b is an obligate aerobic methane-utilizing alpha-proteobacterium. Since its isolation, M. trichosporium OB3b has been established as a model organism to study methane metabolism in type II methanotrophs. M. trichosporium OB3b utilizes soluble and particulate methane monooxygenase (sMMO and pMMO respectively) for methane oxidation. While the source of electrons is known for sMMO, there is less consensus regarding electron donor to pMMO. To investigate this and other questions regarding methane metabolism, the genome-scale metabolic model for M. trichosporium OB3b (model ID: iMsOB3b) was reconstructed. The model accurately predicted oxygen: methane molar uptake ratios and specific growth rates on nitrate-supplemented medium with methane as carbon and energy source. The redox-arm mechanism which links methane oxidation with complex I of electron transport chain has been found to be the most optimal mode of electron transfer. The model was also qualitatively validated on ammonium-supplemented medium indicating its potential to accurately predict methane metabolism in different environmental conditions. Finally, in silico investigations regarding flux distribution in central carbon metabolism of M. trichosporium OB3b were performed. Overall, iMsOB3b can be used as an organism-specific knowledgebase and a platform for hypothesis-driven theoretical investigations of methane metabolism.
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26
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Hofmann M, Retamal-Morales G, Tischler D. Metal binding ability of microbial natural metal chelators and potential applications. Nat Prod Rep 2020; 37:1262-1283. [DOI: 10.1039/c9np00058e] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Metallophores can chelate many different metal and metalloid ions next to iron, make them valuable for many applications.
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Affiliation(s)
- Marika Hofmann
- Institute of Biosciences
- Chemistry and Physics Faculty
- TU Bergakademie Freiberg
- 09599 Freiberg
- Germany
| | - Gerardo Retamal-Morales
- Laboratorio de Microbiología Básica y Aplicada
- Facultad de Química y Biología
- Universidad de Santiago de Chile
- Santiago
- Chile
| | - Dirk Tischler
- Microbial Biotechnology
- Ruhr-Universität Bochum
- 44780 Bochum
- Germany
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27
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Abstract
Chalkophores are bacterial natural products that chelate and transport extracellular copper. The diisonitrile natural product SF2768 was first isolated from a Streptomyces species as an antifungal antibiotic and has more recently been characterized as a bacterial chalkophore and potential virulence factor. Herein, we report a modular synthesis of SF2768 and related acyclic analogues, allowing assignment of syn-stereochemistry across the central lactol ring. The copper-binding properties of these diisonitriles have also been studied.
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Affiliation(s)
- Yao Xu
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Derek S. Tan
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
- Tri-Institutional Research Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
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28
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Einer C, Leitzinger C, Lichtmannegger J, Eberhagen C, Rieder T, Borchard S, Wimmer R, Denk G, Popper B, Neff F, Polishchuk EV, Polishchuk RS, Hauck SM, von Toerne C, Müller JC, Karst U, Baral BS, DiSpirito AA, Kremer AE, Semrau J, Weiss KH, Hohenester S, Zischka H. A High-Calorie Diet Aggravates Mitochondrial Dysfunction and Triggers Severe Liver Damage in Wilson Disease Rats. Cell Mol Gastroenterol Hepatol 2018; 7:571-596. [PMID: 30586623 PMCID: PMC6407159 DOI: 10.1016/j.jcmgh.2018.12.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 12/13/2018] [Accepted: 12/13/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS In Wilson disease, ATP7B mutations impair copper excretion into bile. Hepatic copper accumulation may induce mild to moderate chronic liver damage or even acute liver failure. Etiologic factors for this heterogeneous phenotype remain enigmatic. Liver steatosis is a frequent finding in Wilson disease patients, suggesting that impaired copper homeostasis is linked with liver steatosis. Hepatic mitochondrial function is affected negatively both by copper overload and steatosis. Therefore, we addressed the question of whether a steatosis-promoting high-calorie diet aggravates liver damage in Wilson disease via amplified mitochondrial damage. METHODS Control Atp7b+/- and Wilson disease Atp7b-/- rats were fed either a high-calorie diet (HCD) or a normal diet. Copper chelation using the high-affinity peptide methanobactin was used in HCD-fed Atp7b-/- rats to test for therapeutic reversal of mitochondrial copper damage. RESULTS In comparison with a normal diet, HCD feeding of Atp7b-/- rats resulted in a markedly earlier onset of clinically apparent hepatic injury. Strongly increased mitochondrial copper accumulation was observed in HCD-fed Atp7b-/- rats, correlating with severe liver injury. Mitochondria presented with massive structural damage, increased H2O2 emergence, and dysfunctional adenosine triphosphate production. Hepatocellular injury presumably was augmented as a result of oxidative stress. Reduction of mitochondrial copper by methanobactin significantly reduced mitochondrial impairment and ameliorated liver damage. CONCLUSIONS A high-calorie diet severely aggravates hepatic mitochondrial and hepatocellular damage in Wilson disease rats, causing an earlier onset of the disease and enhanced disease progression.
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Affiliation(s)
- Claudia Einer
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany; Department of Medicine II, University Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Christin Leitzinger
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Josef Lichtmannegger
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Carola Eberhagen
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Tamara Rieder
- Institute of Toxicology and Environmental Hygiene, Technical University Munich, Munich, Germany
| | - Sabine Borchard
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Ralf Wimmer
- Department of Medicine II, University Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Gerald Denk
- Department of Medicine II, University Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Bastian Popper
- Department of Anatomy and Cell Biology, Biomedical Center, Ludwig-Maximilians-University, Planegg-Martinsried, Germany; Core Facility Animal Models, Biomedical Center, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Frauke Neff
- Institute of Pathology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | | | | | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Christine von Toerne
- Research Unit Protein Science, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | | | - Uwe Karst
- Institute of Inorganic and Analytical Chemistry, University of Münster, Münster, Germany
| | - Bipin S Baral
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa
| | - Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa
| | - Andreas E Kremer
- Department of Medicine I, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Jeremy Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan
| | - Karl Heinz Weiss
- Department of Gastroenterology, Internal Medicine IV, University Hospital Heidelberg, Heidelberg, Germany
| | - Simon Hohenester
- Department of Medicine II, University Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Hans Zischka
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany; Institute of Toxicology and Environmental Hygiene, Technical University Munich, Munich, Germany.
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29
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Jia-Ying X, Chun-Yu L, Shuai Z, Yan W, Wei Z, Chun-Gu X. Cu-induced assembly of methanobactin-modified gold nanoparticles and its peroxidase mimic activity. IET Nanobiotechnol 2018; 12:915-921. [PMID: 30247130 DOI: 10.1049/iet-nbt.2018.0069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methanobactin (Mb) is a small copper-chelating molecule that functions as an agent for copper acquisition, uptake and copper-containing methane monooxygenase catalysis in methane-oxidising bacteria. The UV-visible spectral and fluorescence spectral suggested that Mb/Cu coordination complex as a monomer (Mb-Cu), dimmer (Mb2-Cu) and tetramer (Mb4-Cu) could be obtained at different ratios of Mb to Cu (II). The kinetics of the oxidation of hydroquinone with hydrogen peroxide catalysed by the different Mb/Cu coordination complex were investigated. The results suggested that Mb2-Cu coordination form has highest catalytic capacity. Further, Mb-modified gold nanoparticles (AuNPs) were obtained by ligand exchange and assembled into two- and three-D nanocluster structure by metal-organic coordination as driving force. It has been found that AuNPs increased the catalytic activity of Mb2-Cu on AuNPs. The more significant catalytic activity was exhibited by the nanocluster assembly with multi-catalytic centres. This may be attributed to the multivalent collaborative characteristics of the catalytic active centres in the nanocluster network assembly. The assembly of Mb-modified AuNPs can act as excellent nanoenzyme models for imitating peroxidase.
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Affiliation(s)
- Xin Jia-Ying
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China.
| | - Li Chun-Yu
- Key Laboratory for Food Science and Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China
| | - Zhang Shuai
- Key Laboratory for Food Science and Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China
| | - Wang Yan
- Key Laboratory for Food Science and Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China
| | - Zhang Wei
- Key Laboratory for Food Science and Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China
| | - Xia Chun-Gu
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China
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30
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Abstract
Copper-binding metallophores, or chalkophores, play a role in microbial copper homeostasis that is analogous to that of siderophores in iron homeostasis. The best-studied chalkophores are members of the methanobactin (Mbn) family-ribosomally produced, posttranslationally modified natural products first identified as copper chelators responsible for copper uptake in methane-oxidizing bacteria. To date, Mbns have been characterized exclusively in those species, but there is genomic evidence for their production in a much wider range of bacteria. This review addresses the current state of knowledge regarding the function, biosynthesis, transport, and regulation of Mbns. While the roles of several proteins in these processes are supported by substantial genetic and biochemical evidence, key aspects of Mbn manufacture, handling, and regulation remain unclear. In addition, other natural products that have been proposed to mediate copper uptake as well as metallophores that have biologically relevant roles involving copper binding, but not copper uptake, are discussed.
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Affiliation(s)
- Grace E Kenney
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA; ,
| | - Amy C Rosenzweig
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA; ,
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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31
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Kenney GE, Rosenzweig AC. Methanobactins: Maintaining copper homeostasis in methanotrophs and beyond. J Biol Chem 2018; 293:4606-4615. [PMID: 29348173 PMCID: PMC5880147 DOI: 10.1074/jbc.tm117.000185] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Methanobactins (Mbns) are ribosomally produced, post-translationally modified natural products that bind copper with high affinity and specificity. Originally identified in methanotrophic bacteria, which have a high need for copper, operons encoding these compounds have also been found in many non-methanotrophic bacteria. The proteins responsible for Mbn biosynthesis include several novel enzymes. Mbn transport involves export through a multidrug efflux pump and re-internalization via a TonB-dependent transporter. Release of copper from Mbn and the molecular basis for copper regulation of Mbn production remain to be elucidated. Future work is likely to result in the identification of new enzymatic chemistry, opportunities for bioengineering and drug targeting of copper metabolism, and an expanded understanding of microbial metal homeostasis.
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Affiliation(s)
- Grace E Kenney
- Departments of Molecular Biosciences, Evanston, Illinois 60208
| | - Amy C Rosenzweig
- Departments of Molecular Biosciences, Evanston, Illinois 60208; Chemistry, Northwestern University, Evanston, Illinois 60208.
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32
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Abstract
Aerobic methanotrophs have long been known to play a critical role in the global carbon cycle, being capable of converting methane to biomass and carbon dioxide. Interestingly, these microbes exhibit great sensitivity to copper and rare-earth elements, with the expression of key genes involved in the central pathway of methane oxidation controlled by the availability of these metals. That is, these microbes have a "copper switch" that controls the expression of alternative methane monooxygenases and a "rare-earth element switch" that controls the expression of alternative methanol dehydrogenases. Further, it has been recently shown that some methanotrophs can detoxify inorganic mercury and demethylate methylmercury; this finding is remarkable, as the canonical organomercurial lyase does not exist in these methanotrophs, indicating that a novel mechanism is involved in methylmercury demethylation. Here, we review recent findings on methanotrophic interactions with metals, with a particular focus on these metal switches and the mechanisms used by methanotrophs to bind and sequester metals.
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33
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Wang L, Zhu M, Zhang Q, Zhang X, Yang P, Liu Z, Deng Y, Zhu Y, Huang X, Han L, Li S, He J. Diisonitrile Natural Product SF2768 Functions As a Chalkophore That Mediates Copper Acquisition in Streptomyces thioluteus. ACS Chem Biol 2017; 12:3067-3075. [PMID: 29131568 DOI: 10.1021/acschembio.7b00897] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A nonribosomal peptide synthetase (NRPS) gene cluster (sfa) was identified in Streptomyces thioluteus to direct the biosynthesis of the diisonitrile antibiotic SF2768. Its biosynthetic pathway was reasonably proposed based on bioinformatics analysis, metabolic profiles of mutants, and the elucidation of the intermediate and shunt product structures. Bioinformatics-based alignment found a putative ATP-binding cassette (ABC) transporter related to iron import within the biosynthetic gene cluster, which implied that the product might be a siderophore. However, characterization of the metal-binding properties by high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), metal-ligand titration, thin-layer chromatography (TLC), and chrome azurol S (CAS) assays revealed that the final product SF2768 and its diisonitrile derivatives specifically bind copper, rather than iron, to form stable complexes. Inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed that the intracellular cupric content of S. thioluteus significantly increased upon incubation with the copper-SF2768 complex, direct evidence for the copper acquisition function of SF2768. Further in vivo functional characterization of the transport elements for the copper-SF2768 complexes not only confirmed the chalkophore identity of the compound but also gave initial clues into the copper uptake mechanism of this nonmethanotrophic microorganism.
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Affiliation(s)
- Lijuan Wang
- National
Key Laboratory of Agricultural Microbiology, College of Life Science
and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Mengyi Zhu
- National
Key Laboratory of Agricultural Microbiology, College of Life Science
and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qingbo Zhang
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, RNAM
Center for Marine Microbiology, Guangdong Key Laboratory of Marine
Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People’s Republic of China
| | - Xu Zhang
- National
Key Laboratory of Agricultural Microbiology, College of Life Science
and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Panlei Yang
- National
Key Laboratory of Agricultural Microbiology, College of Life Science
and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zihui Liu
- State
Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Yun Deng
- National
Key Laboratory of Agricultural Microbiology, College of Life Science
and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yiguang Zhu
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, RNAM
Center for Marine Microbiology, Guangdong Key Laboratory of Marine
Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People’s Republic of China
| | - Xueshi Huang
- Institute
of Microbial Pharmaceuticals, College of Life and Health Sciences, Northeastern University, Shenyang 110819, China
| | - Li Han
- Institute
of Microbial Pharmaceuticals, College of Life and Health Sciences, Northeastern University, Shenyang 110819, China
| | - Shengqing Li
- State
Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Jing He
- National
Key Laboratory of Agricultural Microbiology, College of Life Science
and Technology, Huazhong Agricultural University, Wuhan 430070, China
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McCabe JW, Vangala R, Angel LA. Binding Selectivity of Methanobactin from Methylosinus trichosporium OB3b for Copper(I), Silver(I), Zinc(II), Nickel(II), Cobalt(II), Manganese(II), Lead(II), and Iron(II). JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2588-2601. [PMID: 28856622 DOI: 10.1007/s13361-017-1778-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/03/2017] [Accepted: 08/04/2017] [Indexed: 05/22/2023]
Abstract
Methanobactin (Mb) from Methylosinus trichosporium OB3b is a member of a class of metal binding peptides identified in methanotrophic bacteria. Mb will selectively bind and reduce Cu(II) to Cu(I), and is thought to mediate the acquisition of the copper cofactor for the enzyme methane monooxygenase. These copper chelating properties of Mb make it potentially useful as a chelating agent for treatment of diseases where copper plays a role including Wilson's disease, cancers, and neurodegenerative diseases. Utilizing traveling wave ion mobility-mass spectrometry (TWIMS), the competition for the Mb copper binding site from Ag(I), Pb(II), Co(II), Fe(II), Mn(II), Ni(II), and Zn(II) has been determined by a series of metal ion titrations, pH titrations, and metal ion displacement titrations. The TWIMS analyses allowed for the explicit identification and quantification of all the individual Mb species present during the titrations and measured their collision cross-sections and collision-induced dissociation patterns. The results showed Ag(I) and Ni(II) could irreversibly bind to Mb and not be effectively displaced by Cu(I), whereas Ag(I) could also partially displace Cu(I) from the Mb complex. At pH ≈ 6.5, the Mb binding selectivity follows the order Ag(I)≈Cu(I)>Ni(II)≈Zn(II)>Co(II)>>Mn(II)≈Pb(II)>Fe(II), and at pH 7.5 to 10.4 the order is Ag(I)>Cu(I)>Ni(II)>Co(II)>Zn(II)>Mn(II)≈Pb(II)>Fe(II). Breakdown curves of the disulfide reduced Cu(I) and Ag(I) complexes showed a correlation existed between their relative stability and their compact folded structure indicated by their CCS. Fluorescence spectroscopy, which allowed the determination of the binding constant, compared well with the TWIMS analyses, with the exception of the Ni(II) complex. Graphical abstract ᅟ.
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Affiliation(s)
- Jacob W McCabe
- Department of Chemistry, Texas A&M University-Commerce, Commerce, TX, 75428, USA
| | - Rajpal Vangala
- Department of Chemistry, Texas A&M University-Commerce, Commerce, TX, 75428, USA
| | - Laurence A Angel
- Department of Chemistry, Texas A&M University-Commerce, Commerce, TX, 75428, USA.
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Abstract
Methanobactins (Mbns) are ribosomally produced, post-translationally modified peptide (RiPP) natural products that bind copper with high affinity using nitrogen-containing heterocycles and thioamide groups. In some methanotrophic bacteria, Mbns are secreted under conditions of copper starvation and then re-internalized as a copper source for the enzyme particulate methane monooxygenase (pMMO). Genome mining studies have led to the identification and classification of operons encoding the Mbn precursor peptide (MbnA) as well as a number of putative transport, regulatory, and biosynthetic proteins. These Mbn operons are present in non-methanotrophic bacteria as well, suggesting a broader role in and perhaps beyond copper acquisition. Genetic and biochemical studies indicate that specific operon-encoded proteins are involved in Mbn transport and provide insight into copper-responsive gene regulation in methanotrophs. Mbn biosynthesis is not yet understood, but combined analysis of Mbn structures, MbnA sequences, and operon content represents a powerful approach to elucidating the roles of specific biosynthetic enzymes. Future work will likely lead to the discovery of unique pathways for natural product biosynthesis and new mechanisms of microbial metal homeostasis.
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Affiliation(s)
- Laura M K Dassama
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
| | - Grace E Kenney
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
| | - Amy C Rosenzweig
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA. and Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
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36
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Šimek M, Elhottová D, Mench M, Giagnoni L, Nannipieri P, Renella G. Greenhouse gas emissions from a Cu-contaminated soil remediated by in situ stabilization and phytomanaged by a mixed stand of poplar, willows, and false indigo-bush. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2017; 19:976-984. [PMID: 28165773 DOI: 10.1080/15226514.2016.1267706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Phytomanagement of trace element-contaminated soils can reduce soil toxicity and restore soil ecological functions, including the soil gas exchange with the atmosphere. We studied the emission rate of the greenhouse gases (GHGs) CO2, CH4, and N2O; the potential CH4 oxidation; denitrification enzyme activity (DEA), and glucose mineralization of a Cu-contaminated soil amended with dolomitic limestone and compost, alone or in combination, after a 2-year phytomanagement with a mixed stand of Populus nigra, Salix viminalis, S. caprea, and Amorpha fruticosa. Soil microbial biomass and microbial community composition after analysis of the phospholipid fatty acids (PLFA) profile were determined. Phytomanagement significantly reduced Cu availability and soil toxicity, increased soil microbial biomass and glucose mineralization capacity, changed the composition of soil microbial communities, and increased the CO2 and N2O emission rates and DEA. Despite such increases, microbial communities were evolving toward less GHG emission per unit of microbial biomass than in untreated soils. Overall, the aided phytostabilization option would allow methanotrophic populations to establish in the remediated soils due to decreased soil toxicity and increased nutrient availability.
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Affiliation(s)
- M Šimek
- a Institute of Soil Biology , Biology Centre CAS , České Budějovice , Czech Republic
- b Faculty of Science , University of South Bohemia , České Budějovice , Czech Republic
| | - D Elhottová
- a Institute of Soil Biology , Biology Centre CAS , České Budějovice , Czech Republic
| | - M Mench
- c BIOGECO, INRA , University of Bordeaux , Pessac , France
| | - L Giagnoni
- d Department of Agrifood Production and Environmental Sciences , University of Florence , Florence , Italy
| | - P Nannipieri
- d Department of Agrifood Production and Environmental Sciences , University of Florence , Florence , Italy
| | - G Renella
- d Department of Agrifood Production and Environmental Sciences , University of Florence , Florence , Italy
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Xin JY, Fan HC, Ji SF, Wang Y, Xia CG. Methanobactin-mediated synthesis of bimetallic Au-Pd/Al 2O 3 toward an efficient catalyst for glucose oxidation. IET Nanobiotechnol 2017; 11:512-516. [PMID: 28745282 PMCID: PMC8676664 DOI: 10.1049/iet-nbt.2016.0168] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/07/2016] [Accepted: 11/22/2016] [Indexed: 11/19/2022] Open
Abstract
A green bioreductive approach with methanobactin was adopted to fabricate bimetallic Au-Pd/Al2O3 catalysts for solvent-free oxidation of glucose to gluconic acid with H2O2 at atmospheric pressure. The catalyst was characterised by diffuse reflectance UV-vis spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction techniques to understand synergistic interactions between Au and Pd. Effects of Au to Pd molar ratio on the catalytic activity of Au-Pd/Al2O3 were investigated. The Au-Pd/Al2O3 catalyst with Au/Pd molar ratio of 0.8:0.2 exhibited excellent catalytic performance. With the catalyst, the oxidation activities of glucose to gluconic acid 2856 mmol min-1 g-1 and selectivity 99.6% were attained at 323 K with H2O2. The results indicated the activity and selectivity was affected by the ratio of Au/Pd on the Al2O3. The formation of Au0.8Pd0.2/Al2O3 was favourable for the catalytic reaction.
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Affiliation(s)
- Jia-Ying Xin
- State Key Laboratory for Oxo Synthesis & Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China.
| | - Hong-Chen Fan
- Key Laboratory for Food Science & Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China
| | - Sheng-Fu Ji
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Yan Wang
- Key Laboratory for Food Science & Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China
| | - Chun-Gu Xia
- State Key Laboratory for Oxo Synthesis & Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China
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An Aminotransferase Is Responsible for the Deamination of the N-Terminal Leucine and Required for Formation of Oxazolone Ring A in Methanobactin of Methylosinus trichosporium OB3b. Appl Environ Microbiol 2016; 83:AEM.02619-16. [PMID: 27795312 DOI: 10.1128/aem.02619-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 10/14/2016] [Indexed: 01/27/2023] Open
Abstract
Gene expression in methanotrophs has been shown to be affected by the availability of a variety of metals, most notably copper-regulating expression of alternative forms of methane monooxygenase. A copper-binding compound, or chalkophore, called methanobactin plays a key role in copper uptake in methanotrophs. Methanobactin is a ribosomally synthesized and posttranslationally modified peptide (RiPP) with two heterocyclic rings with an associated thioamide for each ring, formed from X-Cys dipeptide sequences that bind copper. The gene coding for the precursor polypeptide of methanobactin, mbnA, is part of a gene cluster, but the role of other genes in methanobactin biosynthesis is unclear. To begin to elucidate the function of these genes, we constructed an unmarked deletion of mbnABCMN in Methylosinus trichosporium OB3b and then homologously expressed mbnABCM using a broad-host-range cloning vector to determine the function of mbnN, annotated as coding for an aminotransferase. Methanobactin produced by this strain was found to be substantially different from wild-type methanobactin in that the C-terminal methionine was missing and only one of the two oxazolone rings was formed. Rather, in place of the N-terminal 3-methylbutanoyl-oxazolone-thioamide group, a leucine and a thioamide-containing glycine (Gly-Ψ) were found, indicating that MbnN is used for deamination of the N-terminal leucine of methanobactin and that this posttranslational modification is critical for closure of the N-terminal oxazolone ring in M. trichosporium OB3b. These studies provide new insights into methanobactin biosynthesis and also provide a platform for understanding the function of other genes in the methanobactin gene cluster. IMPORTANCE Methanotrophs, microbes that play a critical role in the carbon cycle, are influenced by copper, with gene expression and enzyme activity changing as copper levels change. Methanotrophs produce a copper-binding compound, or chalkophore, called methanobactin for copper uptake, and methanobactin plays a key role in controlling methanotrophic activity. Methanobactin has also been shown to be effective in the treatment of Wilson disease, an autosomal recessive disorder where the human body cannot correctly assimilate copper. It is important to characterize the methanobactin biosynthesis pathway to understand how methanotrophs respond to their environment as well as to optimize the use of methanobactin for the treatment of copper-related diseases such as Wilson disease. Here we show that mbnN, encoding an aminotransferase, is involved in the deamination of the N-terminal leucine and necessary for the formation of one but not both of the heterocyclic rings in methanobactin that are responsible for copper binding.
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Abstract
Methanotrophic bacteria use methane, a potent greenhouse gas, as their primary source of carbon and energy. The first step in methane metabolism is its oxidation to methanol. In almost all methanotrophs, this chemically challenging reaction is catalyzed by particulate methane monooxygenase (pMMO), a copper-dependent integral membrane enzyme. Methanotrophs acquire copper (Cu) for pMMO by secreting a small ribosomally produced, posttranslationally modified natural product called methanobactin (Mbn). Mbn chelates Cu with high affinity, and the Cu-loaded form (CuMbn) is reinternalized into the cell via an active transport process. Bioinformatic and gene regulation studies suggest that two proteins might play a role in CuMbn handling: the TonB-dependent transporter MbnT and the periplasmic binding protein MbnE. Disruption of the gene that encodes MbnT abolishes CuMbn uptake, as reported previously, and expression of MbnT in Escherichia coli confers the ability to take up CuMbn. Biophysical studies of MbnT and MbnE reveal specific interactions with CuMbn, and a crystal structure of apo MbnE is consistent with MbnE's proposed role as a periplasmic CuMbn transporter. Notably, MbnT and MbnE exhibit different levels of discrimination between cognate and noncognate CuMbns. These findings provide evidence for CuMbn-protein interactions and begin to elucidate the molecular mechanisms of its recognition and transport.
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Lichtmannegger J, Leitzinger C, Wimmer R, Schmitt S, Schulz S, Kabiri Y, Eberhagen C, Rieder T, Janik D, Neff F, Straub BK, Schirmacher P, DiSpirito AA, Bandow N, Baral BS, Flatley A, Kremmer E, Denk G, Reiter FP, Hohenester S, Eckardt-Schupp F, Dencher NA, Adamski J, Sauer V, Niemietz C, Schmidt HHJ, Merle U, Gotthardt DN, Kroemer G, Weiss KH, Zischka H. Methanobactin reverses acute liver failure in a rat model of Wilson disease. J Clin Invest 2016; 126:2721-35. [PMID: 27322060 DOI: 10.1172/jci85226] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 04/12/2016] [Indexed: 12/15/2022] Open
Abstract
In Wilson disease (WD), functional loss of ATPase copper-transporting β (ATP7B) impairs biliary copper excretion, leading to excessive copper accumulation in the liver and fulminant hepatitis. Current US Food and Drug Administration- and European Medicines Agency-approved pharmacological treatments usually fail to restore copper homeostasis in patients with WD who have progressed to acute liver failure, leaving liver transplantation as the only viable treatment option. Here, we investigated the therapeutic utility of methanobactin (MB), a peptide produced by Methylosinus trichosporium OB3b, which has an exceptionally high affinity for copper. We demonstrated that ATP7B-deficient rats recapitulate WD-associated phenotypes, including hepatic copper accumulation, liver damage, and mitochondrial impairment. Short-term treatment of these rats with MB efficiently reversed mitochondrial impairment and liver damage in the acute stages of liver copper accumulation compared with that seen in untreated ATP7B-deficient rats. This beneficial effect was associated with depletion of copper from hepatocyte mitochondria. Moreover, MB treatment prevented hepatocyte death, subsequent liver failure, and death in the rodent model. These results suggest that MB has potential as a therapeutic agent for the treatment of acute WD.
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DiSpirito AA, Semrau JD, Murrell JC, Gallagher WH, Dennison C, Vuilleumier S. Methanobactin and the Link between Copper and Bacterial Methane Oxidation. Microbiol Mol Biol Rev 2016; 80:387-409. [PMID: 26984926 PMCID: PMC4867365 DOI: 10.1128/mmbr.00058-15] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Methanobactins (mbs) are low-molecular-mass (<1,200 Da) copper-binding peptides, or chalkophores, produced by many methane-oxidizing bacteria (methanotrophs). These molecules exhibit similarities to certain iron-binding siderophores but are expressed and secreted in response to copper limitation. Structurally, mbs are characterized by a pair of heterocyclic rings with associated thioamide groups that form the copper coordination site. One of the rings is always an oxazolone and the second ring an oxazolone, an imidazolone, or a pyrazinedione moiety. The mb molecule originates from a peptide precursor that undergoes a series of posttranslational modifications, including (i) ring formation, (ii) cleavage of a leader peptide sequence, and (iii) in some cases, addition of a sulfate group. Functionally, mbs represent the extracellular component of a copper acquisition system. Consistent with this role in copper acquisition, mbs have a high affinity for copper ions. Following binding, mbs rapidly reduce Cu(2+) to Cu(1+). In addition to binding copper, mbs will bind most transition metals and near-transition metals and protect the host methanotroph as well as other bacteria from toxic metals. Several other physiological functions have been assigned to mbs, based primarily on their redox and metal-binding properties. In this review, we examine the current state of knowledge of this novel type of metal-binding peptide. We also explore its potential applications, how mbs may alter the bioavailability of multiple metals, and the many roles mbs may play in the physiology of methanotrophs.
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Affiliation(s)
- Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - J Colin Murrell
- Earth and Life Systems Alliance, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
| | - Warren H Gallagher
- Department of Chemistry, University of Wisconsin-Eau Claire, Eau Claire, Wisconsin, USA
| | - Christopher Dennison
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Stéphane Vuilleumier
- Department of Microbiology, Genomics and the Environment, UMR 7156 UNISTRA-CNRS, Université de Strasbourg, Strasbourg, France
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Lindgren J, Moyer A, Schweitzer MH, Sjövall P, Uvdal P, Nilsson DE, Heimdal J, Engdahl A, Gren JA, Schultz BP, Kear BP. Interpreting melanin-based coloration through deep time: a critical review. Proc Biol Sci 2016; 282:20150614. [PMID: 26290071 DOI: 10.1098/rspb.2015.0614] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Colour, derived primarily from melanin and/or carotenoid pigments, is integral to many aspects of behaviour in living vertebrates, including social signalling, sexual display and crypsis. Thus, identifying biochromes in extinct animals can shed light on the acquisition and evolution of these biological traits. Both eumelanin and melanin-containing cellular organelles (melanosomes) are preserved in fossils, but recognizing traces of ancient melanin-based coloration is fraught with interpretative ambiguity, especially when observations are based on morphological evidence alone. Assigning microbodies (or, more often reported, their 'mouldic impressions') as melanosome traces without adequately excluding a bacterial origin is also problematic because microbes are pervasive and intimately involved in organismal degradation. Additionally, some forms synthesize melanin. In this review, we survey both vertebrate and microbial melanization, and explore the conflicts influencing assessment of microbodies preserved in association with ancient animal soft tissues. We discuss the types of data used to interpret fossil melanosomes and evaluate whether these are sufficient for definitive diagnosis. Finally, we outline an integrated morphological and geochemical approach for detecting endogenous pigment remains and associated microstructures in multimillion-year-old fossils.
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Affiliation(s)
- Johan Lindgren
- Department of Geology, Lund University, 223 62 Lund, Sweden
| | - Alison Moyer
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Mary H Schweitzer
- Department of Geology, Lund University, 223 62 Lund, Sweden Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA
| | - Peter Sjövall
- SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces, 501 15 Borås, Sweden
| | - Per Uvdal
- MAX-IV laboratory, Lund University, 221 00 Lund, Sweden Chemical Physics, Department of Chemistry, Lund University, 221 00 Lund, Sweden
| | - Dan E Nilsson
- Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Jimmy Heimdal
- MAX-IV laboratory, Lund University, 221 00 Lund, Sweden
| | | | - Johan A Gren
- Department of Geology, Lund University, 223 62 Lund, Sweden
| | | | - Benjamin P Kear
- Museum of Evolution, Uppsala University, 752 36 Uppsala, Sweden Palaeobiology Programme, Department of Earth Sciences, Uppsala University, 752 36 Uppsala, Sweden
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44
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Schweitzer MH, Lindgren J, Moyer AE. Melanosomes and ancient coloration re-examined: A response to Vinther 2015 (DOI 10.1002/bies.201500018). Bioessays 2015; 37:1174-83. [PMID: 26434749 DOI: 10.1002/bies.201500061] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Round to elongate microbodies associated with fossil vertebrate soft tissues were interpreted as microbial traces until 2008, when they were re-described as remnant melanosomes - intracellular, pigment-containing eukaryotic organelles. Since then, multiple claims for melanosome preservation and inferences of organismal color, behavior, and physiology have been advanced, based upon the shape and size of these microstructures. Here, we re-examine evidence for ancient melanosomes in light of information reviewed in Vinther (2015), and literature regarding the preservation potential of microorganisms and their exopolymeric secretions. We: (i) address statements in Vinther's recent (2015) review that are incorrect or which misrepresent published data; (ii) discuss the need for caution in interpreting "voids" and microbodies associated with degraded fossil soft tissues; (iii) present evidence that microorganisms are in many cases an equally parsimonious source for these "voids" as are remnant melanosomes; and (iv) suggest methods/criteria for differentiating melanosomes from microbial traces in the fossil record.
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Affiliation(s)
- Mary H Schweitzer
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,North Carolina Museum of Natural Sciences, Raleigh, NC, USA.,Department of Geology, Lund University, Lund, Sweden
| | | | - Alison E Moyer
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
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45
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Cerium regulates expression of alternative methanol dehydrogenases in Methylosinus trichosporium OB3b. Appl Environ Microbiol 2015; 81:7546-52. [PMID: 26296730 DOI: 10.1128/aem.02542-15] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 08/15/2015] [Indexed: 12/25/2022] Open
Abstract
Methanotrophs have multiple methane monooxygenases that are well known to be regulated by copper, i.e., a "copper switch." At low copper/biomass ratios the soluble methane monooxygenase (sMMO) is expressed while expression and activity of the particulate methane monooxygenase (pMMO) increases with increasing availability of copper. In many methanotrophs there are also multiple methanol dehydrogenases (MeDHs), one based on Mxa and another based on Xox. Mxa-MeDH is known to have calcium in its active site, while Xox-MeDHs have been shown to have rare earth elements in their active site. We show here that the expression levels of Mxa-MeDH and Xox-MeDH in Methylosinus trichosporium OB3b significantly decreased and increased, respectively, when grown in the presence of cerium but the absence of copper compared to the absence of both metals. Expression of sMMO and pMMO was not affected. In the presence of copper, the effect of cerium on gene expression was less significant, i.e., expression of Mxa-MeDH in the presence of copper and cerium was slightly lower than in the presence of copper alone, but Xox-MeDH was again found to increase significantly. As expected, the addition of copper caused sMMO and pMMO expression levels to significantly decrease and increase, respectively, but the simultaneous addition of cerium had no discernible effect on MMO expression. As a result, it appears Mxa-MeDH can be uncoupled from methane oxidation by sMMO in M. trichosporium OB3b but not from pMMO.
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Wang Z, Lv X, Chen Y, Liu D, Xu X, Palmore GTR, Hurt RH. Crumpled graphene nanoreactors. NANOSCALE 2015; 7:10267-10278. [PMID: 25992964 DOI: 10.1039/c5nr00963d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nanoreactors are material structures that provide engineered internal cavities that create unique confined nanoscale environments for chemical reactions. Crumpled graphene nanoparticles or "nanosacks" may serve as nanoreactors when filled with reactive or catalytic particles and engineered for a specific chemical function. This article explores the behavior of crumpled graphene nanoreactors containing nanoscale ZnO, Ag, Ni, Cu, Fe, or TiO2 particles, either alone or in combination, in a series of case studies designed to reveal their fundamental behaviors. The first case study shows that ZnO nanoparticles undergo rapid dissolution inside the nanoreactor cavity accompanied by diffusive release of soluble products to surrounding aqueous media through the irregular folded shell. This behavior demonstrates the open nature of the sack structure, which facilitates rapid small-molecule exchange between inside and outside that is a requirement for nanoreactor function. In a case study on copper and silver nanoparticles, encapsulation in graphene nanoreactors is shown in some cases to enhance their oxidation rate in aqueous media, which is attributed to electron transfer from the metal core to graphene that bypasses surface oxides and allows reduction of molecular oxygen on the high-area graphene shell. Nanoreactors also allow particle-particle electron transfer interactions that are mediated by the connecting conductive graphene, which give rise to novel behaviors such as galvanic protection of Ag nanoparticles in Ag/Ni-filled nanoreactors, and the photochemical control of Ag-ion release in Ag/TiO2-filled nanoreactors. It is also shown that internal graphene structures within the sacks provide pockets that reduce particle mobility and inhibit particle sintering during thermal treatment. Finally, these novel behaviors are used to suggest and demonstrate several potential applications for graphene nanoreactors in catalysts, controlled release, and environmental remediation.
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Affiliation(s)
- Zhongying Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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Choi D, Alshahrani AA, Vytla Y, Deeconda M, Serna VJ, Saenz RF, Angel LA. Redox activity and multiple copper(I) coordination of 2His-2Cys oligopeptide. JOURNAL OF MASS SPECTROMETRY : JMS 2015; 50:316-25. [PMID: 25800013 DOI: 10.1002/jms.3530] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 05/07/2023]
Abstract
Copper binding motifs with their molecular mechanisms of selective copper(I) recognition are essential molecules for acquiring copper ions, trafficking copper to specific locations and controlling the potentially damaging redox activities of copper in biochemical processes. The redox activity and multiple Cu(I) binding of an analog methanobactin peptide-2 (amb2) with the sequence acetyl-His1-Cys2-Tyr3-Pro4-His5-Cys6 was investigated using ion mobility-mass spectrometry (IM-MS) and UV-Vis spectrophotometry analyses. The Cu(II) titration of amb2 showed oxidation of amb2 via the formation of intra- and intermolecular Cys-Cys disulfide bridges and the multiple Cu(I) coordination by unoxidized amb2 or the partially oxidized dimer and trimer of amb2. The principal product of these reactions was [amb2 + 3Cu(I)](+) which probably coordinates the three Cu(I) ions via two bridging thiolate groups of Cys2 and Cys6 and the δN6 of the imidazole groups of His6, as determined by geometry optimized structures at the B3LYP/LanL2DZ level of theory. The products observed by IM-MS showed direct correlation to spectral changes associated with disulfide bond formation in the UV-Vis spectrophotometric study. The results show that IM-MS analysis is a powerful technique for unambiguously determining the major ion species produced during the redox and metal binding chemistry of oligopeptides.
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Affiliation(s)
- DongWon Choi
- Department of Biology and Environmental Sciences, Texas A&M University-Commerce, TX, 75428, USA
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Methanobactin from Methylocystis sp. strain SB2 affects gene expression and methane monooxygenase activity in Methylosinus trichosporium OB3b. Appl Environ Microbiol 2015; 81:2466-73. [PMID: 25616801 DOI: 10.1128/aem.03981-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methanotrophs can express a cytoplasmic (soluble) methane monooxygenase (sMMO) or membrane-bound (particulate) methane monooxygenase (pMMO). Expression of these MMOs is strongly regulated by the availability of copper. Many methanotrophs have been found to synthesize a novel compound, methanobactin (Mb), that is responsible for the uptake of copper, and methanobactin produced by Methylosinus trichosporium OB3b plays a key role in controlling expression of MMO genes in this strain. As all known forms of methanobactin are structurally similar, it was hypothesized that methanobactin from one methanotroph may alter gene expression in another. When Methylosinus trichosporium OB3b was grown in the presence of 1 μM CuCl2, expression of mmoX, encoding a subunit of the hydroxylase component of sMMO, was very low. mmoX expression increased, however, when methanobactin from Methylocystis sp. strain SB2 (SB2-Mb) was added, as did whole-cell sMMO activity, but there was no significant change in the amount of copper associated with M. trichosporium OB3b. If M. trichosporium OB3b was grown in the absence of CuCl2, the mmoX expression level was high but decreased by several orders of magnitude if copper prebound to SB2-Mb (Cu-SB2-Mb) was added, and biomass-associated copper was increased. Exposure of Methylosinus trichosporium OB3b to SB2-Mb had no effect on expression of mbnA, encoding the polypeptide precursor of methanobactin in either the presence or absence of CuCl2. mbnA expression, however, was reduced when Cu-SB2-Mb was added in both the absence and presence of CuCl2. These data suggest that methanobactin acts as a general signaling molecule in methanotrophs and that methanobactin "piracy" may be commonplace.
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Methanobactin-mediated synthesis of gold nanoparticles supported over Al2O3 toward an efficient catalyst for glucose oxidation. Int J Mol Sci 2014; 15:21603-20. [PMID: 25429424 PMCID: PMC4284666 DOI: 10.3390/ijms151221603] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 10/27/2014] [Accepted: 11/04/2014] [Indexed: 11/16/2022] Open
Abstract
Methanobactin (Mb) is a copper-binding peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and reduce Au(III) to Au(0). In this paper, Au/Al2O3 catalysts prepared by a novel incipient wetness-Mb-mediated bioreduction method were used for glucose oxidation. The catalysts were characterized, and the analysis revealed that very small gold nanoparticles with a particle size <4 nm were prepared by the incipient wetness-Mb-mediated bioreduction method, even at 1.0% Au loading (w/w). The influence of Au loading, calcination temperature and calcination time on the specific activity of Au/Al2O3 catalysts was systematically investigated. Experimental results showed that decomposing the Mb molecules properly by calcinations can enhance the specific activity of Au/Al2O3 catalysts, though they acted as reductant and protective agents during the catalyst preparation. Au/Al2O3 catalysts synthesized by the method exhibited optimum specific activity under operational synthesis conditions of Au loading of 1.0 wt % and calcined at 450 °C for 2 h. The catalysts were reused eight times, without a significant decrease in specific activity. To our knowledge, this is the first attempt at the preparation of Au/Al2O3 catalysts by Mb-mediated in situ synthesis of gold nanoparticles.
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