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Teixeira RM, Sakamoto IK, Motteran F, Camargo FP, Varesche MBA. Removal of nonylphenol ethoxylate surfactant in batch reactors: emphasis on methanogenic potential and microbial community characterization under optimized conditions. ENVIRONMENTAL TECHNOLOGY 2024; 45:1343-1357. [PMID: 36352347 DOI: 10.1080/09593330.2022.2143287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
ABSTRACTNonylphenol ethoxylate (NPE) is an endocrine-disrupting chemical that has bioaccumulative, persistent and toxic characteristics in different environmental matrices and is difficult to remove in sewage treatment plants. In this study, the effects of the initial concentration of NPE (0.2 ± 0.03 - 3.0 ± 0.02 mg. L-1) and ethanol (73.9 ± 5.0-218.6 ± 10.6 mg. L-1) were investigated using factorial design. Assays were carried out in anaerobic batch reactors, using the Zinder basal medium, yeast extract (200 mg. L-1), vitamin solution and sodium bicarbonate (10% v/v). The optimal conditions were 218.56 mg.L-1 of ethanol and 1596.51 µg.L-1 of NPE, with 92% and 88% of NPE and organic matter removal, respectively, and methane yield (1689.8 ± 59.6 mmol) after 450 h of operation. In this condition, bacteria potentially involved in the degradation of this surfactant were identified in greater relative abundance, such as Acetoanaerobium (1.68%), Smithella (1.52%), Aminivibrio (0.91%), Petrimonas (0.57%) and Enterobacter (0.47%), as well as archaea Methanobacterium and Methanoregula, mainly involved in hydrogenotrophic pathway.
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Affiliation(s)
- Rômulo Mota Teixeira
- Department of Hydraulic Engineering and Sanitation, São Carlos School of Engineering (EESC), University of São Paulo (USP), São Paulo, Brazil
| | - Isabel Kimiko Sakamoto
- Department of Hydraulic Engineering and Sanitation, São Carlos School of Engineering (EESC), University of São Paulo (USP), São Paulo, Brazil
| | - Fabrício Motteran
- Department of Civil and Environmental Engineering, Federal University of Pernambuco, Recife, Brazil
| | - Franciele Pereira Camargo
- Department of Hydraulic Engineering and Sanitation, São Carlos School of Engineering (EESC), University of São Paulo (USP), São Paulo, Brazil
| | - Maria Bernadete Amâncio Varesche
- Department of Hydraulic Engineering and Sanitation, São Carlos School of Engineering (EESC), University of São Paulo (USP), São Paulo, Brazil
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Sahoo RK, Sarkar N, Nembenna S. Intermediates, Isolation and Mechanistic Insights into Zinc Hydride-Catalyzed 1,2-Regioselective Hydrofunctionalization of N-Heteroarenes. Inorg Chem 2023; 62:304-317. [PMID: 36571301 DOI: 10.1021/acs.inorgchem.2c03389] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The conjugated bis-guanidinate-supported zinc hydride [{LZnH}2; L = {(ArHN) (ArN)-C═N-C═(NAr) (NHAr); Ar = 2,6-Et2-C6H3}] (I)-catalyzed highly demanding exclusive 1,2-regioselective hydroboration and hydrosilylation of N-heteroarenes is demonstrated with excellent yields. This protocol is compatible with many pyridines and N-heteroarene derivatives, including electron-donating and -withdrawing substituents. Catalytic intermediates, such as [(LZnH) (4-methylpyridine)] IIA, [(L'ZnH) (4-methylpyridine) IIA', where L' = CH{(CMe) (2,6-Et2C6H3N)}2)], LZn(1,2-DhiQ) (isoquinoline) III, [L'Zn(1,2-DhiQ) (isoquinoline)] III', and LZn(1,2-(3-MeDHQ)) (3-methylquinoline) V, were isolated and thoroughly characterized by NMR, HRMS, and IR analyses. Furthermore, X-ray single-crystal diffraction studies confirmed the molecular structures of compounds IIA', III, and III'. The NMR data proved that the intermediate III or III' reacted with HBpin and gave a selective 1,2-addition hydroborated product. Stoichiometric experiments suggest that V and III independently reacted with silane, yielding selective 1,2-addition of mono- and bis-hydrosilylated products, respectively. Based on the isolation of intermediates and a series of stoichiometric experiments, plausible catalytic cycles were established. Furthermore, the intermolecular chemoselective hydroboration reaction over other reducible functionalities was studied.
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Affiliation(s)
- Rajata Kumar Sahoo
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, Odisha 752 050, India
| | - Nabin Sarkar
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, Odisha 752 050, India
| | - Sharanappa Nembenna
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), Homi Bhabha National Institute (HBNI), Bhubaneswar, Odisha 752 050, India
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Structural basis for coupled ATP-driven electron transfer in the double-cubane cluster protein. Proc Natl Acad Sci U S A 2022; 119:e2203576119. [PMID: 35905315 PMCID: PMC9351452 DOI: 10.1073/pnas.2203576119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Electron transfers coupled to the hydrolysis of ATP allow various metalloenzymes to catalyze reductions at very negative reduction potentials. The double-cubane cluster protein (DCCP) catalyzes the reduction of small molecules, such as acetylene and hydrazine, with electrons provided by its cognate ATP-hydrolyzing reductase (DCCP-R). How ATP-driven electron transfer occurs is not known. To resolve the structural basis for ATP-driven electron transfer, we solved the structures of the DCCP:DCCP-R complex in three different states. The structures show that the DCCP-R homodimer is covalently bridged by a [4Fe4S] cluster that is aligned with the twofold axis of the DCCP homodimer, positioning the [4Fe4S] cluster to enable electron transfer to both double-cubane clusters in the DCCP dimer. DCCP and DCCP-R form stable complexes independent of oxidation state or nucleotides present, and electron transfer requires the hydrolysis of ATP. Electron transfer appears to be additionally driven by modulating the angle between the helices binding the [4Fe4S] cluster. We observed hydrogen bond networks running from the ATP binding site via the [4Fe4S] cluster in DCCP-R to the double-cubane cluster in DCCP, allowing the propagation of conformational changes. Remarkable similarities between the DCCP:DCCP-R complex and the nonhomologous nitrogenases suggest a convergent evolution of catalytic strategies to achieve ATP-driven electron transfers between iron-sulfur clusters.
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Properties and Mechanisms of Flavin-Dependent Monooxygenases and Their Applications in Natural Product Synthesis. Int J Mol Sci 2022; 23:ijms23052622. [PMID: 35269764 PMCID: PMC8910399 DOI: 10.3390/ijms23052622] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/21/2022] [Accepted: 02/25/2022] [Indexed: 11/17/2022] Open
Abstract
Natural products are usually highly complicated organic molecules with special scaffolds, and they are an important resource in medicine. Natural products with complicated structures are produced by enzymes, and this is still a challenging research field, its mechanisms requiring detailed methods for elucidation. Flavin adenine dinucleotide (FAD)-dependent monooxygenases (FMOs) catalyze many oxidation reactions with chemo-, regio-, and stereo-selectivity, and they are involved in the synthesis of many natural products. In this review, we introduce the mechanisms for different FMOs, with the classical FAD (C4a)-hydroperoxide as the major oxidant. We also summarize the difference between FMOs and cytochrome P450 (CYP450) monooxygenases emphasizing the advantages of FMOs and their specificity for substrates. Finally, we present examples of FMO-catalyzed synthesis of natural products. Based on these explanations, this review will expand our knowledge of FMOs as powerful enzymes, as well as implementation of the FMOs as effective tools for biosynthesis.
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Behera D, Thiyagarajan S, Anjalikrishna PK, Suresh CH, Gunanathan C. Ruthenium(II)-Catalyzed Regioselective 1,2-Hydrosilylation of N-Heteroarenes and Tetrel Bonding Mechanism. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01148] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Deepak Behera
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar 752050, India
| | - Subramanian Thiyagarajan
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar 752050, India
| | - Puthannur K. Anjalikrishna
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Cherumuttathu H. Suresh
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Chidambaram Gunanathan
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar 752050, India
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Hollmann F, Opperman DJ, Paul CE. Biocatalytic Reduction Reactions from a Chemist's Perspective. Angew Chem Int Ed Engl 2021; 60:5644-5665. [PMID: 32330347 PMCID: PMC7983917 DOI: 10.1002/anie.202001876] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Indexed: 11/09/2022]
Abstract
Reductions play a key role in organic synthesis, producing chiral products with new functionalities. Enzymes can catalyse such reactions with exquisite stereo-, regio- and chemoselectivity, leading the way to alternative shorter classical synthetic routes towards not only high-added-value compounds but also bulk chemicals. In this review we describe the synthetic state-of-the-art and potential of enzymes that catalyse reductions, ranging from carbonyl, enone and aromatic reductions to reductive aminations.
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Affiliation(s)
- Frank Hollmann
- Department of BiotechnologyDelft University of TechnologyVan der Maasweg 92629 HZDelftThe Netherlands
- Department of BiotechnologyUniversity of the Free State205 Nelson Mandela DriveBloemfontein9300South Africa
| | - Diederik J. Opperman
- Department of BiotechnologyUniversity of the Free State205 Nelson Mandela DriveBloemfontein9300South Africa
| | - Caroline E. Paul
- Department of BiotechnologyDelft University of TechnologyVan der Maasweg 92629 HZDelftThe Netherlands
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Zhang W, Li H, Younes SHH, Gómez de Santos P, Tieves F, Grogan G, Pabst M, Alcalde M, Whitwood AC, Hollmann F. Biocatalytic Aromaticity-Breaking Epoxidation of Naphthalene and Nucleophilic Ring-Opening Reactions. ACS Catal 2021; 11:2644-2649. [PMID: 33763289 PMCID: PMC7976598 DOI: 10.1021/acscatal.0c05588] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/29/2021] [Indexed: 02/06/2023]
Abstract
![]()
Aromatic hydroxylation
reactions catalyzed by heme-thiolate enzymes
proceed via an epoxide intermediate. These aromatic epoxides could
be valuable building blocks for organic synthesis giving access to
a range of chiral trans-disubstituted cyclohexadiene synthons. Here,
we show that naphthalene epoxides generated by fungal peroxygenases
can be subjected to nucleophilic ring opening, yielding non-racemic
trans-disubstituted cyclohexadiene derivates, which in turn can be
used for further chemical transformations. This approach may represent
a promising shortcut for the synthesis of natural products and APIs.
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Affiliation(s)
- Wuyuan Zhang
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin 300308, China
| | - Huanhuan Li
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China
| | - Sabry H. H. Younes
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
- Department of Chemistry, Faculty of Sciences, Sohag University, Sohag 82524, Egypt
| | | | - Florian Tieves
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Gideon Grogan
- York Structural Biology Laboratory, Department of Chemistry, University of York, YO10 5DD York, U.K
| | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
| | - Miguel Alcalde
- Department of Biocatalysis, Institute of Catalysis, CSIC, 28049 Madrid, Spain
| | | | - Frank Hollmann
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, The Netherlands
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8
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Appel L, Willistein M, Dahl C, Ermler U, Boll M. Functional diversity of prokaryotic HdrA(BC) modules: Role in flavin-based electron bifurcation processes and beyond. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148379. [PMID: 33460586 DOI: 10.1016/j.bbabio.2021.148379] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 10/22/2022]
Abstract
In methanogenic archaea, the archetypical complex of heterodisulfide reductase (HdrABC) and hydrogenase (MvhAGD) couples the endergonic reduction of CO2 by H2 to the exergonic reduction of the CoB-S-S-CoM heterodisulfide by H2 via flavin-based electron bifurcation. Presently known enzymes containing HdrA(BC)-like components play key roles in methanogenesis, acetogenesis, respiratory sulfate reduction, lithotrophic reduced sulfur compound oxidation, aromatic compound degradation, fermentations, and probably many further processes. This functional diversity is achieved by a modular architecture of HdrA(BC) enzymes, where a big variety of electron input/output modules may be connected either directly or via adaptor modules to the HdrA(BC) components. Many, but not all HdrA(BC) complexes are proposed to catalyse a flavin-based electron bifurcation/confurcation. Despite the availability of HdrA(BC) crystal structures, fundamental questions of electron transfer and energy coupling processes remain. Here, we address the common properties and functional diversity of HdrA(BC) core modules integrated into electron-transfer machineries of outstanding complexity.
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Affiliation(s)
- Lena Appel
- Fakultät für Biologie - Mikrobiologie, Universität Freiburg, Freiburg, Germany
| | - Max Willistein
- Fakultät für Biologie - Mikrobiologie, Universität Freiburg, Freiburg, Germany
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Ulrich Ermler
- Max-Planck-Institut für Biophysik, Frankfurt, Germany
| | - Matthias Boll
- Fakultät für Biologie - Mikrobiologie, Universität Freiburg, Freiburg, Germany.
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9
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Granatto CF, Grosseli GM, Sakamoto IK, Fadini PS, Varesche MBA. Methanogenic potential of diclofenac and ibuprofen in sanitary sewage using metabolic cosubstrates. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140530. [PMID: 32629260 DOI: 10.1016/j.scitotenv.2020.140530] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Diclofenac (DCF) and ibuprofen (IBU) are widely used anti-inflammatory drugs and are frequently detected in wastewater from Wastewater Treatment Plants and in aquatic environments. In this study, the methanogenic potential (P) of anaerobic sludge subjected to DCF (7.11 ± 0.02 to 44.41 ± 0.05 mg L-1) and IBU (6.11 ± 0.01 to 42.61 ± 0.05 mg L-1), in sanitary sewage, was investigated in batch reactors. Cosubstrates (200 mg L-1 of organic matter) in the form of ethanol, methanol:ethanol and fumarate were tested separately for the removal of drugs. In the DCF assays, P was 6943 ± 121 μmolCH4, 9379 ± 259 μmolCH4, 9897 ± 212 μmolCH4 and 11,530 ± 368 μmolCH4 for control, fumarate, methanol:ethanol and ethanol conditions, respectively. In the IBU assays, under the same conditions, P was 6145 ± 101 μmolCH4, 6947 ± 66 μmolCH4, 8141 ± 191 μmolCH4and 10,583 ± 512 μmolCH4, respectively. Without cosubstrates, drug removal was below 18% for 43.10 ± 0.01 mgDCF L-1 and 43.12 ± 0.03 mgIBU L-1, respectively. Higher P and removal of DCF (28.24 ± 1.10%) and IBU (18.72 ± 1.60%) with ethanol was observed for 43.20 ± 0.01 mgDCF L-1 and 43.42 ± 0.03 mgIBU L-1, respectively. This aspect was better evidenced with DCF due to its molecular structure, a condition that resulted in a higher diversity of bacterial populations. Through the 16S rRNA sequencing, bacteria genera capable of performing aromatic ring cleavage, β-oxidation and oxidation of ethanol and fatty acids were identified. Higher relative abundance (>0.6%) was observed for Smithella, Sulfuricurvum and Synthophus for the Bacteria Domain and Methanosaeta (>79%) for the Archaea Domain. The use of ethanol favored greater mineralization of organic matter and greater methane production, which can directly assist in the metabolic pathways of microorganisms.
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Affiliation(s)
- Caroline F Granatto
- Department of Hydraulics and Sanitation Engineering, São Carlos School of Engineering, University of São Paulo, Ave Trabalhador São-Carlense, No. 400, 13566-590 São Carlos, SP, Brazil..
| | - Guilherme M Grosseli
- Federal University of São Carlos, Washington Luiz Highway, Km 235, 13565-905 São Carlos, SP, Brazil
| | - Isabel K Sakamoto
- Department of Hydraulics and Sanitation Engineering, São Carlos School of Engineering, University of São Paulo, Ave Trabalhador São-Carlense, No. 400, 13566-590 São Carlos, SP, Brazil
| | - Pedro S Fadini
- Federal University of São Carlos, Washington Luiz Highway, Km 235, 13565-905 São Carlos, SP, Brazil
| | - Maria Bernadete A Varesche
- Department of Hydraulics and Sanitation Engineering, São Carlos School of Engineering, University of São Paulo, Ave Trabalhador São-Carlense, No. 400, 13566-590 São Carlos, SP, Brazil..
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10
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Hollmann F, Opperman DJ, Paul CE. Biokatalytische Reduktionen aus der Sicht eines Chemikers. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001876] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Frank Hollmann
- Department of Biotechnology Delft University of Technology Van der Maasweg 9 2629 HZ Delft Niederlande
- Department of Biotechnology University of the Free State 205 Nelson Mandela Drive Bloemfontein 9300 Südafrika
| | - Diederik J. Opperman
- Department of Biotechnology University of the Free State 205 Nelson Mandela Drive Bloemfontein 9300 Südafrika
| | - Caroline E. Paul
- Department of Biotechnology Delft University of Technology Van der Maasweg 9 2629 HZ Delft Niederlande
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Sanchez MLK, Konecny SE, Narehood SM, Reijerse EJ, Lubitz W, Birrell JA, Dyer RB. The Laser-Induced Potential Jump: A Method for Rapid Electron Injection into Oxidoreductase Enzymes. J Phys Chem B 2020; 124:8750-8760. [PMID: 32924491 DOI: 10.1021/acs.jpcb.0c05718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Oxidoreductase enzymes often perform technologically useful chemical transformations using abundant metal cofactors with high efficiency under ambient conditions. The understanding of the catalytic mechanism of these enzymes is, however, highly dependent on the availability of well-characterized and optimized time-resolved analytical techniques. We have developed an approach for rapidly injecting electrons into a catalytic system using a photoactivated nanomaterial in combination with a range of redox mediators to produce a potential jump in solution, which then initiates turnover via electron transfer (ET) to the catalyst. The ET events at the nanomaterial-mediator-catalyst interfaces are, however, highly sensitive to the experimental conditions such as photon flux, relative concentrations of system components, and pH. Here, we present a systematic optimization of these experimental parameters for a specific catalytic system, namely, [FeFe] hydrogenase from Chlamydomonas reinhardtii (CrHydA1). The developed strategies can, however, be applied in the study of a wide variety of oxidoreductase enzymes. Our potential jump system consists of CdSe/CdS core-shell nanorods as a photosensitizer and a series of substituted bipyridinium salts as mediators with redox potentials in the range from -550 to -670 mV (vs SHE). With these components, we screened the effect of pH, mediator concentration, protein concentration, photosensitizer concentration, and photon flux on steady-state photoreduction and hydrogen production as well as ET and potential jump efficiency. By manipulating these experimental conditions, we show the potential of simple modifications to improve the tunability of the potential jump for application to study oxidoreductases.
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Affiliation(s)
- Monica L K Sanchez
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Sara E Konecny
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Sarah M Narehood
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
| | - Edward J Reijerse
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - James A Birrell
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - R Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia 30030, United States
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Irfan RM, Tahir MH, Maqsood M, Lin Y, Bashir T, Iqbal S, Zhao J, Gao L, Haroon M. CoSe as non-noble-metal cocatalyst integrated with heterojunction photosensitizer for inexpensive H2 production under visible light. J Catal 2020. [DOI: 10.1016/j.jcat.2020.07.034] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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13
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Mitschke N, Christoffers J, Wilkes H. A Straightforward Synthesis of Trideuterated α‐Terpinene for Mechanistic Studies. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Nico Mitschke
- Institut für Chemie und Biologie des Meeres (ICBM) Carl von Ossietzky Universität Oldenburg 26111 Oldenburg Germany
| | - Jens Christoffers
- Institut für Chemie Carl von Ossietzky Universität Oldenburg 26111 Oldenburg Germany
| | - Heinz Wilkes
- Institut für Chemie und Biologie des Meeres (ICBM) Carl von Ossietzky Universität Oldenburg 26111 Oldenburg Germany
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Abstract
Tungsten is the heaviest element used in biological systems. It occurs in the active sites of several bacterial or archaeal enzymes and is ligated to an organic cofactor (metallopterin or metal binding pterin; MPT) which is referred to as tungsten cofactor (Wco). Wco-containing enzymes are found in the dimethyl sulfoxide reductase (DMSOR) and the aldehyde:ferredoxin oxidoreductase (AOR) families of MPT-containing enzymes. Some depend on Wco, such as aldehyde oxidoreductases (AORs), class II benzoyl-CoA reductases (BCRs) and acetylene hydratases (AHs), whereas others may incorporate either Wco or molybdenum cofactor (Moco), such as formate dehydrogenases, formylmethanofuran dehydrogenases or nitrate reductases. The obligately tungsten-dependent enzymes catalyze rather unusual reactions such as ones with extremely low-potential electron transfers (AOR, BCR) or an unusual hydration reaction (AH). In recent years, insights into the structure and function of many tungstoenzymes have been obtained. Though specific and unspecific ABC transporter uptake systems have been described for tungstate and molybdate, only little is known about further discriminative steps in Moco and Wco biosynthesis. In bacteria producing Moco- and Wco-containing enzymes simultaneously, paralogous isoforms of the metal insertase MoeA may be specifically involved in the molybdenum- and tungsten-insertion into MPT, and in targeting Moco or Wco to their respective apo-enzymes. Wco-containing enzymes are of emerging biotechnological interest for a number of applications such as the biocatalytic reduction of CO2, carboxylic acids and aromatic compounds, or the conversion of acetylene to acetaldehyde.
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Enhanced photocatalytic H 2 production under visible light on composite photocatalyst (CdS/NiSe nanorods) synthesized in aqueous solution. J Colloid Interface Sci 2019; 557:1-9. [PMID: 31505332 DOI: 10.1016/j.jcis.2019.09.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/02/2019] [Accepted: 09/03/2019] [Indexed: 11/20/2022]
Abstract
Cocatalysts play a critical role in the activity and stability of photocatalytic systems. Currently, efficient cocatalysts mainly comprise of expensive noble metals. Herein we report a composite photocatalyst consisting of CdS nanorods (NRs) and noble-metal-free cocatalyst NiSe, which efficiently enhances the hydrogen production activity of CdS NRs under visible light. NiSe was synthesized through a facile aqueous solution method and CdS/NiSe NRs composites were prepared by in situ deposition of NiSe on CdS NRs. This provides increased contact between cocatalyst and photosensitizer leading to enhanced electron transfer at the interface of NiSe and CdS. The current photocatalytic system gave the highest hydrogen evolution rate of 340 µmol h-1 under optimal conditions. The enhanced stability of the system was observed for 30 h of irradiation resulting in 14 mmol of hydrogen evolution. The highest AQY of 12% was observed using the 420 nm monochromatic light. In addition, CdS/NiSe NRs showed significant higher H2 evolution rate than that of 1.0 wt% loaded CdS/Pt NRs proving NiSe as highly efficient cocatalyst. Photoluminescence spectra and the photocurrent response were used to confirm the efficient charge transfer at the interface of NiSe and CdS nanorods. The work presented here demonstrates the successful use of an inexpensive, non-noble-metal cocatalyst for enhanced photocatalytic hydrogen production.
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Anselmann SEL, Löffler C, Stärk HJ, Jehmlich N, von Bergen M, Brüls T, Boll M. The class II benzoyl-coenzyme A reductase complex from the sulfate-reducing Desulfosarcina cetonica. Environ Microbiol 2019; 21:4241-4252. [PMID: 31430028 DOI: 10.1111/1462-2920.14784] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/06/2019] [Accepted: 08/18/2019] [Indexed: 12/17/2022]
Abstract
Benzoyl-CoA reductases (BCRs) catalyse a key reaction in the anaerobic degradation pathways of monocyclic aromatic substrates, the dearomatization of benzoyl-CoA (BzCoA) to cyclohexa-1,5-diene-1-carboxyl-CoA (1,5-dienoyl-CoA) at the negative redox potential limit of diffusible enzymatic substrate/product couples (E°' = -622 mV). A 1-MDa class II BCR complex composed of the BamBCDEGHI subunits has so far only been isolated from the Fe(III)-respiring Geobacter metallireducens. It is supposed to drive endergonic benzene ring reduction at an active site W-pterin cofactor by flavin-based electron bifurcation. Here, we identified multiple copies of putative genes encoding the structural components of a class II BCR in sulfate reducing, Fe(III)-respiring and syntrophic bacteria. A soluble 950 kDa Bam[(BC)2 DEFGHI]2 complex was isolated from extracts of Desulfosarcina cetonica cells grown with benzoate/sulfate. Metal and cofactor analyses together with the identification of conserved binding motifs gave rise to 4 W-pterins, two selenocysteines, six flavin adenine dinucleotides, four Zn, and 48 FeS clusters. The complex exhibited 1,5-dienoyl-CoA-, NADPH- and ferredoxin-dependent oxidoreductase activities. Our results indicate that high-molecular class II BCR metalloenzyme machineries are remarkably conserved in strictly anaerobic bacteria with regard to subunit architecture and cofactor content, but their subcellular localization and electron acceptor preference may differ as a result of adaptations to variable energy metabolisms.
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Affiliation(s)
| | - Claudia Löffler
- Faculty of Biology - Microbiology, University of Freiburg, 79104, Freiburg, Germany
| | - Hans-Joachim Stärk
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, 04318, Leipzig, Germany
| | - Nico Jehmlich
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research - UFZ, 04318, Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research - UFZ, 04318, Leipzig, Germany.,Faculty of Life Sciences, Institute of Biochemistry, University of Leipzig, Brüderstr. 34, 04103, Leipzig, Germany
| | - Thomas Brüls
- CEA, DRF, IBFJ, Genoscope, Evry, France.,CNRS-UMR8030, Université d'Evry Val d'Essonne and Université Paris-Saclay, Evry, France
| | - Matthias Boll
- Faculty of Biology - Microbiology, University of Freiburg, 79104, Freiburg, Germany
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Pacheco-Sánchez D, Rama-Garda R, Marín P, Martirani-Von Abercron SM, Marqués S. Occurrence and diversity of the oxidative hydroxyhydroquinone pathway for the anaerobic degradation of aromatic compounds in nitrate-reducing bacteria. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:525-537. [PMID: 30884168 DOI: 10.1111/1758-2229.12752] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 03/13/2019] [Indexed: 06/09/2023]
Abstract
The nitrate-reducing betaproteobacteria Azoarcus anaerobius and Thauera aromatica AR-1 use an oxidative mechanism to anaerobically degrade resorcinol and 3,5-dihydroxybenzoate (3,5-DHB), respectively, rendering hydroxyhydroquinone as intermediate. The first pathway step is performed by a dimethylsulphoxide-reductase family hydroxylase. The gene cluster coding for the pathway is homologous in these strains. Only these two Rhodocyclales are known to follow this anaerobic pathway, and nothing is known about its distribution in prokaryotes. To determine the relevance and diversity of this strategy in nature, we enriched for bacteria able to oxidize resorcinol or 3,5-DHB under denitrifying conditions. Nitrate-reducing bacteria able to degrade these compounds were present in soil, aquifer and marine sediments. We were able to isolate a number of strains with this capacity from soil and aquifer samples. Amplicon libraries of rehL, the gene encoding the first step of this pathway, showed an overall low diversity, most sequences clustering with either pathway enzyme. Isolates belonging to the Beta- and Gammaproteobacteria able to grow on these substrates revealed rehL homologues only in strains belonging to Thauera and Azoarcus. Analysis of sequenced genomes in the databases detected the presence of highly similar clusters in two additional betaproteobacteria and in the gammaproteobacterium Sedimenticola selenatireducens, although anaerobic growth on a dihydroxyaromatic could only be confirmed in Thauera chlorobenzoica 3CB-1. The presence of mobile elements in the flanking sequences of some of the clusters suggested events of horizontal gene transfer, probably contributing to expand the pathway to a broader host range within the Proteobacteria.
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Affiliation(s)
- Daniel Pacheco-Sánchez
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, Profesor Albareda 1, E-18008, Granada, Spain
| | - Ramón Rama-Garda
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, Profesor Albareda 1, E-18008, Granada, Spain
| | - Patricia Marín
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, Profesor Albareda 1, E-18008, Granada, Spain
| | - Sophie-Marie Martirani-Von Abercron
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, Profesor Albareda 1, E-18008, Granada, Spain
| | - Silvia Marqués
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, Profesor Albareda 1, E-18008, Granada, Spain
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19
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Geiger RA, Junghare M, Mergelsberg M, Ebenau‐Jehle C, Jesenofsky VJ, Jehmlich N, von Bergen M, Schink B, Boll M. Enzymes involved in phthalate degradation in sulphate‐reducing bacteria. Environ Microbiol 2019; 21:3601-3612. [DOI: 10.1111/1462-2920.14681] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/03/2019] [Accepted: 05/11/2019] [Indexed: 12/31/2022]
Affiliation(s)
| | - Madan Junghare
- Department of Biology, Microbial EcologyUniversity of Konstanz, 78457 Constance Germany
| | - Mario Mergelsberg
- Faculty of Biology–MicrobiologyUniversity of Freiburg, 79104 Freiburg Germany
| | | | | | - Nico Jehmlich
- Department of Molecular Systems BiologyHelmholtz Centre for Environmental Research UFZ 04318 Leipzig Germany
| | - Martin von Bergen
- Department of Molecular Systems BiologyHelmholtz Centre for Environmental Research UFZ 04318 Leipzig Germany
- Institute of Biochemistry, Faculty of Life SciencesUniversity of Leipzig Brüderstr. 34, 04103 Leipzig Germany
| | - Bernhard Schink
- Department of Biology, Microbial EcologyUniversity of Konstanz, 78457 Constance Germany
| | - Matthias Boll
- Faculty of Biology–MicrobiologyUniversity of Freiburg, 79104 Freiburg Germany
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20
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Abstract
The family Geobacteraceae, with its only valid genus Geobacter, comprises deltaproteobacteria ubiquitous in soil, sediments, and subsurface environments where metal reduction is an active process. Research for almost three decades has provided novel insights into environmental processes and biogeochemical reactions not previously known to be carried out by microorganisms. At the heart of the environmental roles played by Geobacter bacteria is their ability to integrate redox pathways and regulatory checkpoints that maximize growth efficiency with electron donors derived from the decomposition of organic matter while respiring metal oxides, particularly the often abundant oxides of ferric iron. This metabolic specialization is complemented by versatile metabolic reactions, respiratory chains, and sensory networks that allow specific members to adaptively respond to environmental cues to integrate organic and inorganic contaminants in their oxidative and reductive metabolism, respectively. Thus, Geobacteraceae are important members of the microbial communities that degrade hydrocarbon contaminants under iron-reducing conditions and that contribute, directly or indirectly, to the reduction of radionuclides, toxic metals, and oxidized species of nitrogen. Their ability to produce conductive pili as nanowires for discharging respiratory electrons to solid-phase electron acceptors and radionuclides, or for wiring cells in current-harvesting biofilms highlights the unique physiological traits that make these organisms attractive biological platforms for bioremediation, bioenergy, and bioelectronics application. Here we review some of the most notable physiological features described in Geobacter species since the first model representatives were recovered in pure culture. We provide a historical account of the environmental research that has set the foundation for numerous physiological studies and the laboratory tools that had provided novel insights into the role of Geobacter in the functioning of microbial communities from pristine and contaminated environments. We pay particular attention to latest research, both basic and applied, that has served to expand the field into new directions and to advance interdisciplinary knowledge. The electrifying physiology of Geobacter, it seems, is alive and well 30 years on.
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Low potential enzymatic hydride transfer via highly cooperative and inversely functionalized flavin cofactors. Nat Commun 2019; 10:2074. [PMID: 31061390 PMCID: PMC6502838 DOI: 10.1038/s41467-019-10078-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/12/2019] [Indexed: 02/01/2023] Open
Abstract
Hydride transfers play a crucial role in a multitude of biological redox reactions and are mediated by flavin, deazaflavin or nicotinamide adenine dinucleotide cofactors at standard redox potentials ranging from 0 to –340 mV. 2-Naphthoyl-CoA reductase, a key enzyme of oxygen-independent bacterial naphthalene degradation, uses a low-potential one-electron donor for the two-electron dearomatization of its substrate below the redox limit of known biological hydride transfer processes at E°’ = −493 mV. Here we demonstrate by X-ray structural analyses, QM/MM computational studies, and multiple spectroscopy/activity based titrations that highly cooperative electron transfer (n = 3) from a low-potential one-electron (FAD) to a two-electron (FMN) transferring flavin cofactor is the key to overcome the resonance stabilized aromatic system by hydride transfer in a highly hydrophobic pocket. The results evidence how the protein environment inversely functionalizes two flavins to switch from low-potential one-electron to hydride transfer at the thermodynamic limit of flavin redox chemistry. The reduction of 2-naphtoyl-CoA to 5,6 dihydro-2-naphtoyl-CoA by 2-naphtoyl-CoA reductase is below the negative redox limit usually encountered in biological hydride transfer. Here, via X-ray crystallography and spectroscopic analysis, the authors elucidated the mechanism behind this.
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22
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One-megadalton metalloenzyme complex in Geobacter metallireducens involved in benzene ring reduction beyond the biological redox window. Proc Natl Acad Sci U S A 2019; 116:2259-2264. [PMID: 30674680 DOI: 10.1073/pnas.1819636116] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Reversible biological electron transfer usually occurs between redox couples at standard redox potentials ranging from +0.8 to -0.5 V. Dearomatizing benzoyl-CoA reductases (BCRs), key enzymes of the globally relevant microbial degradation of aromatic compounds at anoxic sites, catalyze a biological Birch reduction beyond the negative limit of this redox window. The structurally characterized BamBC subunits of class II BCRs accomplish benzene ring reduction at an active-site tungsten cofactor; however, the mechanism and components involved in the energetic coupling of endergonic benzene ring reduction have remained hypothetical. We present a 1-MDa, membrane-associated, Bam[(BC)2DEFGHI]2 complex from the anaerobic bacterium Geobacter metallireducens harboring 4 tungsten, 4 zinc, 2 selenocysteines, 6 FAD, and >50 FeS cofactors. The results suggest that class II BCRs catalyze electron transfer to the aromatic ring, yielding a cyclic 1,5-dienoyl-CoA via two flavin-based electron bifurcation events. This work expands our knowledge of energetic couplings in biology by high-molecular-mass electron bifurcating machineries.
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DbdR, a New Member of the LysR Family of Transcriptional Regulators, Coordinately Controls Four Promoters in the Thauera aromatica AR-1 3,5-Dihydroxybenzoate Anaerobic Degradation Pathway. Appl Environ Microbiol 2019; 85:AEM.02295-18. [PMID: 30389770 DOI: 10.1128/aem.02295-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 10/24/2018] [Indexed: 12/27/2022] Open
Abstract
The facultative anaerobe Thauera aromatica strain AR-1 uses 3,5-dihydroxybenzoate (3,5-DHB) as a sole carbon and energy source under anoxic conditions using an unusual oxidative strategy to overcome aromatic ring stability. A 25-kb gene cluster organized in four main operons encodes the anaerobic degradation pathway for this aromatic. The dbdR gene coding for a LysR-type transcriptional regulator (LTTR), which is present at the foremost end of the cluster, is required for anaerobic growth on 3,5-DHB and for the expression of the main pathway operons. A model structure of DbdR showed conserved key residues for effector binding with its closest relative TsaR for p-toluenesulfonate degradation. We found that DbdR controlled expression of three promoters upstream from the operons coding for the three main steps of the pathway. While one of them (P orf20 ) was only active in the presence of 3,5-DHB, the other two (P dbhL and P orf18 ) showed moderate basal levels that were further induced in the presence of the pathway substrate, which needed be converted to hydroxyhydroquinone to activate transcription. Both basal and induced activities were strictly dependent on DbdR, which was also required for transcription from its own promoter. DbdR basal expression was moderately high and, unlike most LTTR, increased 2-fold in response to the presence of the effector. DbdR was found to be a tetramer in solution, producing a single retardation complex in binding assays with the three enzymatic promoters, consistent with its tetrameric structure. The three promoters had a conserved organization with a clear putative primary (regulatory) binding site and a putative secondary (activating) binding site positioned at the expected distances from the transcription start site. In contrast, two protein-DNA complexes were observed for the P dbdR promoter, which also showed significant sequence divergence from those of the three other promoters. Taken together, our results show that a single LTTR coordinately controls expression of the entire 3,5-DHB anaerobic degradation pathway in Thauera aromatica AR-1, allowing a fast and optimized response to the presence of the aromatic.IMPORTANCE Thauera aromatica AR-1 is a facultative anaerobe that is able to use 3,5-dihydroxybenzoat (3,5-DHB) as the sole carbon and energy source in a process that is dependent on nitrate respiration. We have shown that a single LysR-type regulator with unusual properties, DbdR, controls the expression of the pathway in response to the presence of the substrate; unlike other regulators of the family, DbdR does not repress but activates its own synthesis and is able to bind and activate three promoters directing the synthesis of the pathway enzymes. The promoter architecture is conserved among the three promoters but deviates from that of typical LTTR-dependent promoters. The substrate must be metabolized to an intermediate compound to activate transcription, which requires basal enzyme levels to always be present. The regulatory network present in this strain is designed to allow basal expression of the enzymatic machinery, which would rapidly metabolize the substrate when exposed to it, thus rendering the effector molecule. Once activated, the regulator induces the synthesis of the entire pathway through a positive feedback, increasing expression from all the target promoters to allow maximum growth.
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24
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Motteran F, Nadai BM, Braga JK, Silva EL, Varesche MBA. Metabolic routes involved in the removal of linear alkylbenzene sulfonate (LAS) employing linear alcohol ethoxylated and ethanol as co-substrates in enlarged scale fluidized bed reactor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 640-641:1411-1423. [PMID: 30021307 DOI: 10.1016/j.scitotenv.2018.05.375] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/28/2018] [Accepted: 05/30/2018] [Indexed: 06/08/2023]
Abstract
In this study, the microbial community characterization and metabolic pathway identification involved in the linear alkylbenzene sulfonated (LAS) degradation from commercial laundry wastewater in a fluidized bed reactor (FBR) on an increased scale were performed using the Illumina MiSeq platform. Ethanol and non-ionic surfactant (LAE, Genapol C-100) were used as co-substrates. The FBR was operated in five operational phases: (I) synthetic substrate for inoculation; (II) 7.9 ± 4.7 mg/L LAS and 11.7 ± 6.9 mg/L LAE; (III) 19.4 ± 12.9 mg/L LAS, 19.6 ± 9.2 mg/L LAE and 205 mg/L ethanol; (IV) 25.9 ± 11 mg/L LAS, 19.5 ± 9.1 mg/L LAE and 205 mg/L ethanol and (V) 43.9 ± 18 mg/L LAS, 25 ± 9.8 mg/L LAE and 205 mg/L ethanol. At all operation phases, organic matter was removed from 40.4 to 85.1% and LAS removal was from 24.7 to 56%. Sulfate-reducing bacteria (SRB) were identified in the biofilm of FBR in all operational phases. Although the LAS promoted a toxic effect on the microbiota, this effect can be reduced when using biodegradable co-substrates, such as ethanol and LAE, which was observed in Phase IV. In this phase, there was a greater microbial diversity (Shannon index) and higher microorganism richness (Chao 1 index), both for the Domain Bacteria, and for the Domain Archaea.
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Affiliation(s)
- Fabricio Motteran
- Department of Hydraulics and Sanitation, School of Engineering of São Carlos, University of São Paulo, Av. Trabalhador Sãocarlense, 400, 13566-590 São Carlos, SP, Brazil.
| | - Bianca Marques Nadai
- Department of Hydraulics and Sanitation, School of Engineering of São Carlos, University of São Paulo, Av. Trabalhador Sãocarlense, 400, 13566-590 São Carlos, SP, Brazil
| | - Juliana Kawanishi Braga
- Department of Hydraulics and Sanitation, School of Engineering of São Carlos, University of São Paulo, Av. Trabalhador Sãocarlense, 400, 13566-590 São Carlos, SP, Brazil
| | - Edson Luiz Silva
- Department of Chemical Engineering, Federal University of São Carlos, Rod. Washington Luiz, Km 235, SP 310, 13565-905 São Carlos, SP, Brazil
| | - Maria Bernadete Amâncio Varesche
- Department of Hydraulics and Sanitation, School of Engineering of São Carlos, University of São Paulo, Av. Trabalhador Sãocarlense, 400, 13566-590 São Carlos, SP, Brazil.
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Qian HX, Liao RZ. QM/MM Study of Tungsten-Dependent Benzoyl-Coenzyme A Reductase: Rationalization of Regioselectivity and Predication of W vs Mo Selectivity. Inorg Chem 2018; 57:10667-10678. [DOI: 10.1021/acs.inorgchem.8b01328] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hui-Xia Qian
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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26
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Willistein M, Haas J, Fuchs J, Estelmann S, Ferlaino S, Müller M, Lüdeke S, Boll M. Enantioselective Enzymatic Naphthoyl Ring Reduction. Chemistry 2018; 24:12505-12508. [PMID: 29932261 DOI: 10.1002/chem.201802683] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Indexed: 01/10/2023]
Abstract
Birch reductions of aromatic hydrocarbons by means of single-electron-transfer steps depend on alkali metals, ammonia, and cryogenic reaction conditions. In contrast, 2-naphthoyl-coenzyme A (2-NCoA) and 5,6-dihydro-2-NCoA (5,6-DHNCoA) reductases catalyze two two-electron reductions of the naphthoyl-ring system to tetrahydronaphthoyl-CoA at ambient temperature. Using a number of substrate analogues, we provide evidence for a Meisenheimer complex-analogous intermediate during 2-NCoA reduction, whereas the subsequent reduction of 5,6-dihydro-2-NCoA is suggested to proceed via an unprecedented cationic transition state. Using vibrational circular dichroism (VCD) spectroscopy, we demonstrate that both enzymatic reductions are highly stereoselective in D2 O, providing an enantioselective pathway to products inaccessible by Birch reduction. Moreover, we demonstrate the power of VCD spectroscopy to determine the absolute configuration of isotopically engendered alicyclic stereocenters.
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Affiliation(s)
- Max Willistein
- Institute of Biology, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
| | - Julian Haas
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
| | - Jonathan Fuchs
- Institute of Biology, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
| | - Sebastian Estelmann
- Institute of Biology, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
| | - Sascha Ferlaino
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
| | - Michael Müller
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
| | - Steffen Lüdeke
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
| | - Matthias Boll
- Institute of Biology, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
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27
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Tiedt O, Fuchs J, Eisenreich W, Boll M. A catalytically versatile benzoyl-CoA reductase, key enzyme in the degradation of methyl- and halobenzoates in denitrifying bacteria. J Biol Chem 2018; 293:10264-10274. [PMID: 29769313 DOI: 10.1074/jbc.ra118.003329] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/15/2018] [Indexed: 12/22/2022] Open
Abstract
Class I benzoyl-CoA (BzCoA) reductases (BCRs) are key enzymes in the anaerobic degradation of aromatic compounds. They catalyze the ATP-dependent reduction of the central BzCoA intermediate and analogues of it to conjugated cyclic 1,5-dienoyl-CoAs probably by a radical-based, Birch-like reduction mechanism. Discovered in 1995, the enzyme from the denitrifying bacterium Thauera aromatica (BCRTar) has so far remained the only isolated and biochemically accessible BCR, mainly because BCRs are extremely labile, and their heterologous production has largely failed so far. Here, we describe a platform for the heterologous expression of the four structural genes encoding a designated 3-methylbenzoyl-CoA reductase from the related denitrifying species Thauera chlorobenzoica (MBRTcl) in Escherichia coli This reductase represents the prototype of a distinct subclass of ATP-dependent BCRs that were proposed to be involved in the degradation of methyl-substituted BzCoA analogues. The recombinant MBRTcl had an αβγδ-subunit architecture, contained three low-potential [4Fe-4S] clusters, and was highly oxygen-labile. It catalyzed the ATP-dependent reductive dearomatization of BzCoA with 2.3-2.8 ATPs hydrolyzed per two electrons transferred and preferentially dearomatized methyl- and chloro-substituted analogues in meta- and para-positions. NMR analyses revealed that 3-methylbenzoyl-CoA is regioselectively reduced to 3-methyl-1,5-dienoyl-CoA. The unprecedented reductive dechlorination of 4-chloro-BzCoA to BzCoA probably via HCl elimination from a reduced intermediate allowed for the previously unreported growth of T. chlorobenzoica on 4-chlorobenzoate. The heterologous expression platform established in this work enables the production, isolation, and characterization of bacterial and archaeal BCR and BCR-like radical enzymes, for many of which the function has remained unknown.
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Affiliation(s)
- Oliver Tiedt
- From the Fakultät für Biologie-Mikrobiologie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany and
| | - Jonathan Fuchs
- From the Fakultät für Biologie-Mikrobiologie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany and
| | - Wolfgang Eisenreich
- Lehrstuhl für Biochemie, Technische Universität München, 85747 Garching, Germany
| | - Matthias Boll
- From the Fakultät für Biologie-Mikrobiologie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany and
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28
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Culka M, Huwiler SG, Boll M, Ullmann GM. Breaking Benzene Aromaticity-Computational Insights into the Mechanism of the Tungsten-Containing Benzoyl-CoA Reductase. J Am Chem Soc 2017; 139:14488-14500. [PMID: 28918628 DOI: 10.1021/jacs.7b07012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatic compounds are environmental pollutants with toxic and carcinogenic properties. Despite the stability of aromatic rings, bacteria are able to degrade the aromatic compounds into simple metabolites and use them as growth substrates under oxic or even under anoxic conditions. In anaerobic microorganisms, most monocyclic aromatic growth substrates are converted to the central intermediate benzoyl-coenzyme A, which is enzymatically reduced to cyclohexa-1,5-dienoyl-CoA. The strictly anaerobic bacterium Geobacter metallireducens uses the class II benzoyl-CoA reductase complex for this reaction. The catalytic BamB subunit of this complex harbors an active site tungsten-bis-pyranopterin cofactor with the metal being coordinated by five protein/cofactor-derived sulfur atoms and a sixth, so far unknown, ligand. Although BamB has been biochemically and structurally characterized, its mechanism still remains elusive. Here we use continuum electrostatic and QM/MM calculations to model benzoyl-CoA reduction by BamB. We aim to elucidate the identity of the sixth ligand of the active-site tungsten ion together with the interplay of the electron and proton transfer events during the aromatic ring reduction. On the basis of our calculations, we propose that benzoyl-CoA reduction is initiated by a hydrogen atom transfer from a W(IV) species with an aqua ligand, yielding W(V)-[OH-] and a substrate radical intermediate. In the next step, a proton-assisted second electron transfer takes place with a conserved active-site histidine serving as the second proton donor. Interestingly, our calculations suggest that the electron for the second reduction step is taken from the pyranopterin cofactors rather than from the tungsten ion. The resulting cationic radical, which is distributed over both pyranopterins, is stabilized by conserved anionic amino acid residues. The stepwise mechanism of the reduction shows similarities to the Birch reduction known from organic chemistry. However, the strict coupling of protons and electrons allows the reaction to proceed under milder conditions.
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Affiliation(s)
- Martin Culka
- Computational Biochemistry, University of Bayreuth , Universitätsstrasse 30, NW I, 95447 Bayreuth, Germany
| | - Simona G Huwiler
- Microbiology, Faculty of Biology, University of Freiburg , Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Matthias Boll
- Microbiology, Faculty of Biology, University of Freiburg , Schänzlestrasse 1, 79104 Freiburg, Germany
| | - G Matthias Ullmann
- Computational Biochemistry, University of Bayreuth , Universitätsstrasse 30, NW I, 95447 Bayreuth, Germany
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29
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Mergelsberg M, Willistein M, Meyer H, Stärk HJ, Bechtel DF, Pierik AJ, Boll M. Phthaloyl-coenzyme A decarboxylase from Thauera chlorobenzoica: the prenylated flavin-, K + - and Fe 2+ -dependent key enzyme of anaerobic phthalate degradation. Environ Microbiol 2017; 19:3734-3744. [PMID: 28752942 DOI: 10.1111/1462-2920.13875] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/14/2017] [Accepted: 07/24/2017] [Indexed: 10/19/2022]
Abstract
The degradation of the industrially produced and environmentally relevant phthalate esters by microorganisms is initiated by the hydrolysis to alcohols and phthalate (1,2-dicarboxybenzene). In the absence of oxygen the further degradation of phthalate proceeds via activation to phthaloyl-CoA followed by decarboxylation to benzoyl-CoA. Here, we report on the first purification and characterization of a phthaloyl-CoA decarboxylase (PCD) from the denitrifying Thauera chlorobenzoica. Hexameric PCD belongs to the UbiD-family of (de)carboxylases and contains prenylated FMN (prFMN), K+ and, unlike other UbiD-like enzymes, Fe2+ as cofactors. The latter is suggested to be involved in oxygen-independent electron-transfer during oxidative prFMN maturation. Either oxidation to the Fe3+ -state in air or removal of K+ by desalting resulted in >92% loss of both, prFMN and decarboxylation activity suggesting the presence of an active site prFMN/Fe2+ /K+ -complex in PCD. The PCD-catalysed reaction was essentially irreversible: neither carboxylation of benzoyl-CoA in the presence of 2 M bicarbonate, nor an isotope exchange of phthaloyl-CoA with 13 C-bicarbonate was observed. PCD differs in many aspects from prFMN-containing UbiD-like decarboxylases and serves as a biochemically accessible model for the large number of UbiD-like (de)carboxylases that play key roles in the anaerobic degradation of environmentally relevant aromatic pollutants.
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Affiliation(s)
- Mario Mergelsberg
- Faculty of Biology, Department of Microbiology, University of Freiburg, Freiburg, Germany
| | - Max Willistein
- Faculty of Biology, Department of Microbiology, University of Freiburg, Freiburg, Germany
| | - Heike Meyer
- Faculty of Biology, Department of Microbiology, University of Freiburg, Freiburg, Germany
| | - Hans-Joachim Stärk
- Department of Analytics, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | | | - Antonio J Pierik
- Department of Chemistry, TU Kaiserslautern, Kaiserslautern, Germany
| | - Matthias Boll
- Faculty of Biology, Department of Microbiology, University of Freiburg, Freiburg, Germany
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The Azoarcus anaerobius 1,3-Dihydroxybenzene (Resorcinol) Anaerobic Degradation Pathway Is Controlled by the Coordinated Activity of Two Enhancer-Binding Proteins. Appl Environ Microbiol 2017; 83:AEM.03042-16. [PMID: 28258136 DOI: 10.1128/aem.03042-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 02/22/2017] [Indexed: 11/20/2022] Open
Abstract
The anaerobic resorcinol degradation pathway in Azoarcus anaerobius is unique in that it uses an oxidative rather than a reductive strategy to overcome the aromatic ring stability in degradation of this compound, in a process that is dependent on nitrate respiration. We show that the pathway is organized in five transcriptional units, three of which are inducible by the presence of the substrate. Three σ54-dependent promoters located upstream from the three operons coding for the main pathway enzymes were identified, which shared a similar structure with conserved upstream activating sequences (UASs) located at 103 to 111 bp from the transcription start site. Expression of the pathway is controlled by the bacterial enhancer-binding proteins (bEBPs) RedR1 and RedR2, two homologous regulators that, despite their high sequence identity (97%), have nonredundant functions: RedR2, the master regulator which also controls RedR1 expression, is itself able to promote transcription from two of the promoters, while RedR1 activity is strictly dependent on the presence of RedR2. The two regulators were shown to interact with each other, suggesting that the natural mode of activation is by forming heterodimers, which become active in the presence of the substrate after its metabolization to hydroxybenzoquinone through the pathway enzymes. The model structure of the N-terminal domain of the proteins is composed of tandem GAF and PAS motifs; the possible mechanisms controlling the activity of the regulators are discussed.IMPORTANCEAzoarcus anaerobius is a strict anaerobe that is able to use 1,3-dihydroxybenzene as the sole carbon source in a process that is dependent on nitrate respiration. We have shown that expression of the pathway is controlled by two regulators of almost identical sequences: the bEBPs RedR1 and RedR2, which share 97% identity. These regulators control three promoters with similar structure. Despite their sequence identity, the two bEBPs are not redundant and are both required for maximum pathway expression. In fact, the two proteins function as heterodimers and require activation by the pathway intermediate hydroxyhydroquinone. The structure of the domain sensing the activation signal resembles that of regulators that are known to interact with other proteins.
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Lin CI, McCarty RM, Liu HW. The Enzymology of Organic Transformations: A Survey of Name Reactions in Biological Systems. Angew Chem Int Ed Engl 2017; 56:3446-3489. [PMID: 27505692 PMCID: PMC5477795 DOI: 10.1002/anie.201603291] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Indexed: 01/05/2023]
Abstract
Chemical reactions that are named in honor of their true, or at least perceived, discoverers are known as "name reactions". This Review is a collection of biological representatives of named chemical reactions. Emphasis is placed on reaction types and catalytic mechanisms that showcase both the chemical diversity in natural product biosynthesis as well as the parallels with synthetic organic chemistry. An attempt has been made, whenever possible, to describe the enzymatic mechanisms of catalysis within the context of their synthetic counterparts and to discuss the mechanistic hypotheses for those reactions that are currently active areas of investigation. This Review has been categorized by reaction type, for example condensation, nucleophilic addition, reduction and oxidation, substitution, carboxylation, radical-mediated, and rearrangements, which are subdivided by name reactions.
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Affiliation(s)
- Chia-I Lin
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, and Department of Chemistry, University of Texas at Austin, Austin, TX, 78731, USA
| | - Reid M McCarty
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, and Department of Chemistry, University of Texas at Austin, Austin, TX, 78731, USA
| | - Hung-Wen Liu
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, and Department of Chemistry, University of Texas at Austin, Austin, TX, 78731, USA
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Zanello P. The competition between chemistry and biology in assembling iron–sulfur derivatives. Molecular structures and electrochemistry. Part V. {[Fe4S4](SCysγ)4} proteins. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2016.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Lin C, McCarty RM, Liu H. Die Enzymologie organischer Umwandlungen: Namensreaktionen in biologischen Systemen. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201603291] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Chia‐I. Lin
- Division of Chemical Biology and Medicinal Chemistry College of Pharmacy, and Department of Chemistry University of Texas at Austin Austin TX 78731 USA
| | - Reid M. McCarty
- Division of Chemical Biology and Medicinal Chemistry College of Pharmacy, and Department of Chemistry University of Texas at Austin Austin TX 78731 USA
| | - Hung‐wen Liu
- Division of Chemical Biology and Medicinal Chemistry College of Pharmacy, and Department of Chemistry University of Texas at Austin Austin TX 78731 USA
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Chen H, Jiang D, Sun Z, Irfan RM, Zhang L, Du P. Cobalt nitride as an efficient cocatalyst on CdS nanorods for enhanced photocatalytic hydrogen production in water. Catal Sci Technol 2017. [DOI: 10.1039/c7cy00046d] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Noble-metal-free cobalt nitride (Co3N) can be used as a novel cocatalyst on CdS nanorods for photocatalytic H2production in water under visible light irradiation.
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Affiliation(s)
- Huanlin Chen
- Key Laboratory of Materials for Energy Conversion
- Chinese Academy of Sciences
- Department of Materials Science and Engineering
- and the Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- University of Science and Technology of China
| | - Daochuan Jiang
- Key Laboratory of Materials for Energy Conversion
- Chinese Academy of Sciences
- Department of Materials Science and Engineering
- and the Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- University of Science and Technology of China
| | - Zijun Sun
- Key Laboratory of Materials for Energy Conversion
- Chinese Academy of Sciences
- Department of Materials Science and Engineering
- and the Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- University of Science and Technology of China
| | - Rana Muhammad Irfan
- Key Laboratory of Materials for Energy Conversion
- Chinese Academy of Sciences
- Department of Materials Science and Engineering
- and the Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- University of Science and Technology of China
| | - Lei Zhang
- Key Laboratory of Materials for Energy Conversion
- Chinese Academy of Sciences
- Department of Materials Science and Engineering
- and the Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- University of Science and Technology of China
| | - Pingwu Du
- Key Laboratory of Materials for Energy Conversion
- Chinese Academy of Sciences
- Department of Materials Science and Engineering
- and the Collaborative Innovation Center of Chemistry for Energy Materials (iChEM)
- University of Science and Technology of China
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Jiang D, Irfan RM, Sun Z, Lu D, Du P. Synergistic Effect of a Molecular Cocatalyst and a Heterojunction in a 1 D Semiconductor Photocatalyst for Robust and Highly Efficient Solar Hydrogen Production. CHEMSUSCHEM 2016; 9:3084-3092. [PMID: 27730758 DOI: 10.1002/cssc.201600871] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Indexed: 06/06/2023]
Abstract
Photocatalytic production of hydrogen by water splitting is a promising pathway for the conversion of solar energy into chemical energy. However, the photocatalytic conversion efficiency is often limited by the sluggish transfer of the photogenerated charge carriers, charge recombination, and subsequent slow catalytic reactions. Herein, we report a highly active noble-metal-free photocatalytic system for hydrogen production in water. The system contains a water-soluble nickel complex as a molecular cocatalyst and zinc sulfide on 1D cadmium sulfide as the heterojunction photocatalyst. The complex can efficiently transport photogenerated electrons and holes over a heterojunction photocatalyst to hamper charge recombination, leading to highly improved catalytic efficiency and durability of a heterojunction photocatalyst- molecular cocatalyst system. The results show that under optimal conditions, the average apparent quantum yield was approximately 58.3 % after 7 h of irradiation with monochromatic 420 nm light. In contrast, the value is only 16.8 % if the molecular cocatalyst is absent. Such a remarkable performance in a molecular cocatalyst-based photocatalytic system without any noble metal loading has, to the best of our knowledge, not been reported to date.
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Affiliation(s)
- Daochuan Jiang
- Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, 96 Jinzhai Road, 230026, Hefei, Anhui Province, P.R. China
| | - Rana Muhammad Irfan
- Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, 96 Jinzhai Road, 230026, Hefei, Anhui Province, P.R. China
| | - Zijun Sun
- Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, 96 Jinzhai Road, 230026, Hefei, Anhui Province, P.R. China
| | - Dapeng Lu
- Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, 96 Jinzhai Road, 230026, Hefei, Anhui Province, P.R. China
| | - Pingwu Du
- Key Laboratory of Materials for Energy Conversion, Chinese Academy of Sciences, Department of Materials Science and Engineering, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, 96 Jinzhai Road, 230026, Hefei, Anhui Province, P.R. China
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Schmid G, Auerbach H, Pierik AJ, Schünemann V, Boll M. ATP-Dependent Electron Activation Module of Benzoyl-Coenzyme A Reductase from the Hyperthermophilic Archaeon Ferroglobus placidus. Biochemistry 2016; 55:5578-5586. [PMID: 27597116 DOI: 10.1021/acs.biochem.6b00729] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The class I benzoyl-coenzyme A (BzCoA) reductases (BCRs) are key enzymes in the anaerobic degradation of aromatic compounds that catalyze the ATP-dependent dearomatization of their substrate to a cyclic dienoyl-CoA. The phylogenetically distinct Thauera- and Azoarcus-type BCR subclasses are iron-sulfur enzymes and consist of an ATP-hydrolyzing electron activation module and a BzCoA reduction module. More than 20 years after their initial identification, all biochemical information about class I BCRs derives from studies of the wild-type enzyme from the denitrifying bacterium Thauera aromatica (BCRTaro). Here, we describe the first heterologous production and purification of the ATP-hydrolyzing, electron-activating module of an Azoarcus-type BCR from the hyperthermophilic archaeon Ferroglobus placidus, BzdPQFpla. The Fe content, UV/vis spectroscopic, and Mössbauer spectroscopic properties of the 57Fe-enriched enzyme clearly identified a [4Fe-4S]+/2+ cluster with a redox potential (E°') of -376 mV as a cofactor. ATP hydrolysis is required to overcome a redox barrier of ∼250 mV for stoichiometric electron transfer from the [4Fe-4S]+ cluster to the substrate benzene ring (E°'BzCoA/dienoyl-CoA = -622 mV). BzdPQFpla exhibited ATPase activity (15 nmol min-1 mg-1; Km = 270 μM) at 75 °C, which was relatively stable in air in contrast to BCRTaro. The results obtained revealed high levels of functional and molecular similarity between Azoarcus-type BCRs and the homologous ATP-dependent activator components of 2-hydroxyacyl-CoA dehydratases involved in amino acid fermentations. Insights into the diversity and evolution of ATP-dependent electron-activating modules for catalytic or stoichiometric low-potential electron transfer processes are presented.
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Affiliation(s)
- Georg Schmid
- Fakultät für Biologie-Mikrobiologie, Institut für Biologie II, Albert-Ludwigs-Universität Freiburg , D-79104 Freiburg, Germany
| | - Hendrik Auerbach
- Fachbereich Physik, TU Kaiserslautern , 67663 Kaiserslautern, Germany
| | - Antonio J Pierik
- Fachbereich Chemie, TU Kaiserslautern , 67663 Kaiserslautern, Germany
| | - Volker Schünemann
- Fachbereich Physik, TU Kaiserslautern , 67663 Kaiserslautern, Germany
| | - Matthias Boll
- Fakultät für Biologie-Mikrobiologie, Institut für Biologie II, Albert-Ludwigs-Universität Freiburg , D-79104 Freiburg, Germany
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Jeong J, Park S, Chang S. Iridium-catalyzed selective 1,2-hydrosilylation of N-heterocycles. Chem Sci 2016; 7:5362-5370. [PMID: 30155189 PMCID: PMC6020754 DOI: 10.1039/c6sc01037g] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 04/26/2016] [Indexed: 01/05/2023] Open
Abstract
A silylene-bridged Ir dimer in situ generated from [Ir(coe)2Cl]2 and Et2SiH2 was found to catalyze the hydrosilylation of N-heteroaromatics to furnish dearomatized azacyclic products with high activity (up to 1000 TONs), excellent selectivity, and good functional group tolerance. The substrate scope was highly broad, including (iso)quinolines, substituted pyridines, pyrimidines, pyrazines, deazapurines, triazines, and benzimidazoles. Mechanistic studies such as a kinetic profile, rate-order assessment, and investigation of the electronic substituent effects on the initial rates were performed to access the detailed pathways. One pathway is proposed to involve an intramolecular insertion of the C[double bond, length as m-dash]N moiety of the substrates into the Ir-H bond of a resting species to form an Ir-amido silyl intermediate, followed by reductive elimination. The synthetic utility was proven by successful application to cinchona alkaloids, and facile post-synthetic transformations of the 1,2-dihydroquinoline products.
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Affiliation(s)
- Jinseong Jeong
- Department of Chemistry , Korea Advanced Institute of Science & Technology (KAIST) , Daejeon 305-701 , South Korea . ; .,Center for Catalytic Hydrocarbon Functionalizations , Institute for Basic Science (IBS) , Daejeon 305-701 , South Korea
| | - Sehoon Park
- Department of Chemistry , Korea Advanced Institute of Science & Technology (KAIST) , Daejeon 305-701 , South Korea . ; .,Center for Catalytic Hydrocarbon Functionalizations , Institute for Basic Science (IBS) , Daejeon 305-701 , South Korea
| | - Sukbok Chang
- Department of Chemistry , Korea Advanced Institute of Science & Technology (KAIST) , Daejeon 305-701 , South Korea . ; .,Center for Catalytic Hydrocarbon Functionalizations , Institute for Basic Science (IBS) , Daejeon 305-701 , South Korea
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Boll M, Kung JW, Ermler U, Martins BM, Buckel W. Fermentative Cyclohexane Carboxylate Formation in Syntrophus aciditrophicus. J Mol Microbiol Biotechnol 2016; 26:165-79. [PMID: 26959729 DOI: 10.1159/000440881] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Short-chain fatty acids such as acetic, propionic, butyric or lactic acids are typical primary fermentation products in the anaerobic feeding chain. Fifteen years ago, a novel fermentation type was discovered in the obligately anaerobic Deltaproteobacterium Syntrophus aciditrophicus. During fermentative growth with crotonate and/or benzoate, acetate is formed in the oxidative branch and cyclohexane carboxylate in the reductive branch. In both cases cyclohexa-1,5-diene-1-carboxyl-CoA (Ch1,5CoA) is a central intermediate that is either formed by a class II benzoyl-CoA reductase (fermentation of benzoate) or by reverse reactions of the benzoyl-CoA degradation pathway (fermentation of crotonate). Here, we summarize the current knowledge of the enzymology involved in fermentations yielding cyclohexane carboxylate as an excreted product. The characteristic enzymes involved are two acyl-CoA dehydrogenases specifically acting on Ch1,5CoA and cyclohex-1-ene-1-carboxyl-CoA. Both enzymes are also employed during the syntrophic growth of S. aciditrophicus with cyclohexane carboxylate as the carbon source in coculture with a methanogen. An investigation of anabolic pathways in S. aciditrophicus revealed a rather unusual pathway for glutamate synthesis involving a Re-citrate synthase. Future work has to address the unresolved question concerning which components are involved in reoxidation of the NADH formed in the oxidative branch of the unique cyclohexane carboxylate fermentation pathway in S. aciditrophicus.
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Affiliation(s)
- Matthias Boll
- Mikrobiologie, Fakultx00E4;t fx00FC;r Biologie, Albert-Ludwigs-Universitx00E4;t Freiburg, Freiburg, Germany
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Meckenstock RU, Boll M, Mouttaki H, Koelschbach JS, Cunha Tarouco P, Weyrauch P, Dong X, Himmelberg AM. Anaerobic Degradation of Benzene and Polycyclic Aromatic Hydrocarbons. J Mol Microbiol Biotechnol 2016; 26:92-118. [DOI: 10.1159/000441358] [Citation(s) in RCA: 180] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Aromatic hydrocarbons such as benzene and polycyclic aromatic hydrocarbons (PAHs) are very slowly degraded without molecular oxygen. Here, we review the recent advances in the elucidation of the first known degradation pathways of these environmental hazards. Anaerobic degradation of benzene and PAHs has been successfully documented in the environment by metabolite analysis, compound-specific isotope analysis and microcosm studies. Subsequently, also enrichments and pure cultures were obtained that anaerobically degrade benzene, naphthalene or methylnaphthalene, and even phenanthrene, the largest PAH currently known to be degradable under anoxic conditions. Although such cultures grow very slowly, with doubling times of around 2 weeks, and produce only very little biomass in batch cultures, successful proteogenomic, transcriptomic and biochemical studies revealed novel degradation pathways with exciting biochemical reactions such as for example the carboxylation of naphthalene or the ATP-independent reduction of naphthoyl-coenzyme A. The elucidation of the first anaerobic degradation pathways of naphthalene and methylnaphthalene at the genetic and biochemical level now opens the door to studying the anaerobic metabolism and ecology of anaerobic PAH degraders. This will contribute to assessing the fate of one of the most important contaminant classes in anoxic sediments and aquifers.
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Boll M, Einsle O, Ermler U, Kroneck PMH, Ullmann GM. Structure and Function of the Unusual Tungsten Enzymes Acetylene Hydratase and Class II Benzoyl-Coenzyme A Reductase. J Mol Microbiol Biotechnol 2016; 26:119-37. [PMID: 26959374 DOI: 10.1159/000440805] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In biology, tungsten (W) is exclusively found in microbial enzymes bound to a bis-pyranopterin cofactor (bis-WPT). Previously known W enzymes catalyze redox oxo/hydroxyl transfer reactions by directly coordinating their substrates or products to the metal. They comprise the W-containing formate/formylmethanofuran dehydrogenases belonging to the dimethyl sulfoxide reductase (DMSOR) family and the aldehyde:ferredoxin oxidoreductase (AOR) families, which form a separate enzyme family within the Mo/W enzymes. In the last decade, initial insights into the structure and function of two unprecedented W enzymes were obtained: the acetaldehyde forming acetylene hydratase (ACH) belongs to the DMSOR and the class II benzoyl-coenzyme A (CoA) reductase (BCR) to the AOR family. The latter catalyzes the reductive dearomatization of benzoyl-CoA to a cyclic diene. Both are key enzymes in the degradation of acetylene (ACH) or aromatic compounds (BCR) in strictly anaerobic bacteria. They are unusual in either catalyzing a nonredox reaction (ACH) or a redox reaction without coordinating the substrate or product to the metal (BCR). In organic chemical synthesis, analogous reactions require totally nonphysiological conditions depending on Hg2+ (acetylene hydration) or alkali metals (benzene ring reduction). The structural insights obtained pave the way for biological or biomimetic approaches to basic reactions in organic chemistry.
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Affiliation(s)
- Matthias Boll
- Fakultx00E4;t fx00FC;r Biologie/Mikrobiologie, Institut fx00FC;r Biochemie, Albert-Ludwigs-Universitx00E4;t Freiburg, Freiburg, Germany
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41
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Rabus R, Boll M, Golding B, Wilkes H. Anaerobic Degradation of p-Alkylated Benzoates and Toluenes. J Mol Microbiol Biotechnol 2016; 26:63-75. [PMID: 26960059 DOI: 10.1159/000441144] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The anaerobic degradation of 4-alkylbenzoates and 4-alkyltoluenes is to date a rarely reported microbial capacity. The newly isolated Alphaproteobacterium Magnetospirillum sp. strain pMbN1 represents the first pure culture demonstrated to degrade 4-methylbenzoate completely to CO2 in a process coupled to denitrification. Differential proteogenomic studies in conjunction with targeted metabolite analyses and enzyme activity measurements elucidated a specific 4-methylbenzoyl-coenzyme A (CoA) pathway in this bacterium alongside the classical central benzoyl-CoA pathway. Whilst these two pathways are analogous, in the former the p-methyl group is retained and its 4-methylbenzoyl-CoA reductase (MbrCBAD) is phylogenetically distinct from the archetypical class I benzoyl-CoA reductase (BcrCBAD). Subsequent global regulatory studies on strain pMbN1 grown with binary or ternary substrate mixtures revealed benzoate to repress the anaerobic utilization of 4-methylbenzoate and succinate. The shared nutritional property of betaproteobacterial 'Aromatoleum aromaticum' pCyN1 and Thauera sp. strain pCyN2 is the anaerobic degradation of the plant-derived hydrocarbon p-cymene (4-isopropyltoluene) coupled to denitrification. Notably, the two strains employ two different peripheral pathways for the conversion of p-cymene to 4-isopropylbenzoyl-CoA as the possible first common intermediate. In 'A. aromaticum' pCyN1 a putative p-cymene dehydrogenase (CmdABC) is proposed to hydroxylate the benzylic methyl group, which is subsequently further oxidized to the CoA-thioester. In contrast, Thauera sp. strain pCyN2 employs a reaction sequence analogous to the known anaerobic toluene pathway, involving a distinct branching (4-isopropylbenzyl)succinate synthase (IbsABCDEF).
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Affiliation(s)
- Ralf Rabus
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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Weinert T, Huwiler SG, Kung JW, Weidenweber S, Hellwig P, Stärk HJ, Biskup T, Weber S, Cotelesage JJH, George GN, Ermler U, Boll M. Structural basis of enzymatic benzene ring reduction. Nat Chem Biol 2015; 11:586-91. [PMID: 26120796 DOI: 10.1038/nchembio.1849] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 05/15/2015] [Indexed: 12/19/2022]
Abstract
In chemical synthesis, the widely used Birch reduction of aromatic compounds to cyclic dienes requires alkali metals in ammonia as extremely low-potential electron donors. An analogous reaction is catalyzed by benzoyl-coenzyme A reductases (BCRs) that have a key role in the globally important bacterial degradation of aromatic compounds at anoxic sites. Because of the lack of structural information, the catalytic mechanism of enzymatic benzene ring reduction remained obscure. Here, we present the structural characterization of a dearomatizing BCR containing an unprecedented tungsten cofactor that transfers electrons to the benzene ring in an aprotic cavity. Substrate binding induces proton transfer from the bulk solvent to the active site by expelling a Zn(2+) that is crucial for active site encapsulation. Our results shed light on the structural basis of an electron transfer process at the negative redox potential limit in biology. They open the door for biological or biomimetic alternatives to a basic chemical synthetic tool.
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Affiliation(s)
| | - Simona G Huwiler
- Microbiology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Johannes W Kung
- Microbiology, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Petra Hellwig
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, Chimie de la Matière Complexe, Université de Strasbourg-CNRS, Strasbourg, France
| | - Hans-Joachim Stärk
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research UFZ, Leipzig, Germany
| | - Till Biskup
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
| | - Stefan Weber
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
| | - Julien J H Cotelesage
- 1] Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. [2] Canadian Light Source, Saskatoon, Saskatchewan, Canada
| | - Graham N George
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Ulrich Ermler
- Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Matthias Boll
- Microbiology, Faculty of Biology, University of Freiburg, Freiburg, Germany
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Schmid G, René SB, Boll M. Enzymes of the benzoyl-coenzyme A degradation pathway in the hyperthermophilic archaeon Ferroglobus placidus. Environ Microbiol 2015; 17:3289-300. [PMID: 25630364 DOI: 10.1111/1462-2920.12785] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 12/28/2022]
Abstract
The Fe(III)-respiring Ferroglobus placidus is the only known archaeon and hyperthermophile for which a complete degradation of aromatic substrates to CO2 has been reported. Recent genome and transcriptome analyses proposed a benzoyl-coenzyme A (CoA) degradation pathway similar to that found in the phototrophic Rhodopseudomonas palustris, which involves a cyclohex-1-ene-1-carboxyl-CoA (1-enoyl-CoA) forming, ATP-dependent key enzyme benzoyl-CoA reductase (BCR). In this work, we demonstrate, by first in vitro studies, that benzoyl-CoA is ATP-dependently reduced by two electrons to cyclohexa-1,5-dienoyl-CoA (1,5-dienoyl-CoA), which is further degraded by hydration to 6-hydroxycyclohex-1-ene-1-carboxyl-CoA (6-OH-1-enoyl-CoA); upon addition of NAD(+) , the latter was subsequently converted to β-oxidation intermediates. The four candidate genes of BCR were heterologously expressed, and the enriched, oxygen-sensitive enzyme catalysed the two-electron reduction of benzoyl-CoA to 1,5-dienoyl-CoA. A gene previously assigned to a 2,3-didehydropimeloyl-CoA hydratase was heterologously expressed and shown to act as a typical 1,5-dienoyl-CoA hydratase that does not accept 1-enoyl-CoA. A gene previously assigned to a 1-enoyl-CoA hydratase was heterologously expressed and identified to code for a bifunctional crotonase/3-OH-butyryl-CoA dehydrogenase. In summary, the results consistently provide biochemical evidence that F. placidus and probably other archaea predominantly degrade aromatics via the Thauera/Azoarcus type and not or only to a minor extent via the predicted R. palustris-type benzoyl-CoA degradation pathway.
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Affiliation(s)
- Georg Schmid
- Microbiology, Faculty of Biology, University of Freiburg, Schänzlestr. 1, Freiburg, 79104, Germany
| | - Sandra Bosch René
- Microbiology, Faculty of Biology, University of Freiburg, Schänzlestr. 1, Freiburg, 79104, Germany
| | - Matthias Boll
- Microbiology, Faculty of Biology, University of Freiburg, Schänzlestr. 1, Freiburg, 79104, Germany
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Schmidt A, Frensch M, Schleheck D, Schink B, Müller N. Degradation of acetaldehyde and its precursors by Pelobacter carbinolicus and P. acetylenicus. PLoS One 2014; 9:e115902. [PMID: 25536080 PMCID: PMC4275255 DOI: 10.1371/journal.pone.0115902] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/27/2014] [Indexed: 11/19/2022] Open
Abstract
Pelobacter carbinolicus and P. acetylenicus oxidize ethanol in syntrophic cooperation with methanogens. Cocultures with Methanospirillum hungatei served as model systems for the elucidation of syntrophic ethanol oxidation previously done with the lost “Methanobacillus omelianskii” coculture. During growth on ethanol, both Pelobacter species exhibited NAD+-dependent alcohol dehydrogenase activity. Two different acetaldehyde-oxidizing activities were found: a benzyl viologen-reducing enzyme forming acetate, and a NAD+-reducing enzyme forming acetyl-CoA. Both species synthesized ATP from acetyl-CoA via acetyl phosphate. Comparative 2D-PAGE of ethanol-grown P. carbinolicus revealed enhanced expression of tungsten-dependent acetaldehyde: ferredoxin oxidoreductases and formate dehydrogenase. Tungsten limitation resulted in slower growth and the expression of a molybdenum-dependent isoenzyme. Putative comproportionating hydrogenases and formate dehydrogenase were expressed constitutively and are probably involved in interspecies electron transfer. In ethanol-grown cocultures, the maximum hydrogen partial pressure was about 1,000 Pa (1 mM) while 2 mM formate was produced. The redox potentials of hydrogen and formate released during ethanol oxidation were calculated to be EH2 = -358±12 mV and EHCOOH = -366±19 mV, respectively. Hydrogen and formate formation and degradation further proved that both carriers contributed to interspecies electron transfer. The maximum Gibbs free energy that the Pelobacter species could exploit during growth on ethanol was −35 to −28 kJ per mol ethanol. Both species could be cultivated axenically on acetaldehyde, yielding energy from its disproportionation to ethanol and acetate. Syntrophic cocultures grown on acetoin revealed a two-phase degradation: first acetoin degradation to acetate and ethanol without involvement of the methanogenic partner, and subsequent syntrophic ethanol oxidation. Protein expression and activity patterns of both Pelobacter spp. grown with the named substrates were highly similar suggesting that both share the same steps in ethanol and acetalydehyde metabolism. The early assumption that acetaldehyde is a central intermediate in Pelobacter metabolism was now proven biochemically.
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Affiliation(s)
- Alexander Schmidt
- Department of Biology, University of Konstanz, D-78457, Konstanz, Germany
| | - Marco Frensch
- Department of Biology, University of Konstanz, D-78457, Konstanz, Germany
| | - David Schleheck
- Department of Biology, University of Konstanz, D-78457, Konstanz, Germany
| | - Bernhard Schink
- Department of Biology, University of Konstanz, D-78457, Konstanz, Germany
| | - Nicolai Müller
- Department of Biology, University of Konstanz, D-78457, Konstanz, Germany
- * E-mail:
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Estelmann S, Blank I, Feldmann A, Boll M. Two distinct old yellow enzymes are involved in naphthyl ring reduction during anaerobic naphthalene degradation. Mol Microbiol 2014; 95:162-72. [PMID: 25424741 DOI: 10.1111/mmi.12875] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2014] [Indexed: 11/29/2022]
Abstract
The 2-naphthoyl-coenzyme A (NCoA) reductase (NCR) is so far the only characterized enzyme involved in the anaerobic degradation of the environmentally relevant polycyclic aromatic hydrocarbons. The old yellow enzyme (OYE) family member apparently reduced the nonactivated naphthyl ring to 5,6,7,8-tetrahydro-2-napthoyl-CoA (THNCoA). In this work, the candidate genes of three NCRs from the sulphate-reducing, naphthalene-degrading N47 and NaphS2 cultures were expressed in Escherichia coli. The isolated products contained flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN) a [4Fe-4S] cluster and catalyzed only the two-electron reduction of NCoA to 5,6-dihydro-2-naphthoyl-CoA (5,6-DHNCoA) at a very negative E°' = -493 mV. All NCRs exhibited high NCoA-forming DHNCoA oxidase activities that are proposed to be involved in oxygen-detoxification during naphthalene degradation. Extracts of N47 and NaphS2 catalyzed the reduction of 5,6-DHNCoA to THNCoA. Genes putatively coding for 5,6-DHNCR from N47 and NaphS2 were heterologously expressed in E. coli. The enriched enzyme products specifically catalyzed the reduction of 5,6-DHNCoA to THNCoA at E°' = -375 mV. With the three NCRs and two 5,6-DHNCRs, five OYEs have been characterized that are involved in the reduction of the nonsubstituted naphthyl-ring system; these unprecedented enzymatic reactions expand our knowledge of the functional diversity of OYE.
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Affiliation(s)
- Sebastian Estelmann
- Microbiology, Faculty of Biology, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
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Buckel W, Kung JW, Boll M. The benzoyl-coenzyme a reductase and 2-hydroxyacyl-coenzyme a dehydratase radical enzyme family. Chembiochem 2014; 15:2188-94. [PMID: 25204868 DOI: 10.1002/cbic.201402270] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Wolfgang Buckel
- Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität Marburg, Karl-von-Frisch-Strasse 8, 35043 Marburg (Germany)
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Porter AW, Young LY. Benzoyl-CoA, a universal biomarker for anaerobic degradation of aromatic compounds. ADVANCES IN APPLIED MICROBIOLOGY 2014; 88:167-203. [PMID: 24767428 DOI: 10.1016/b978-0-12-800260-5.00005-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Aromatic compounds are a major component of the global carbon pool and include a diverse range of compounds such as humic acid, lignin, amino acids, and industrial contaminants. Due to the prevalence of aromatic compounds in the environment, aerobic and anaerobic microorganisms have evolved mechanisms by which to metabolize that available carbon. Less well understood are the anaerobic pathways. We now know that anaerobic metabolism of a variety of monoaromatic compounds can be initiated in a number of different ways, and a key metabolite for these pathways is benzoyl-CoA. Chemicals can have different upstream anaerobic degradation pathways yet can still be assessed by targeting the downstream benzoyl-CoA pathway. In this pathway, we propose that the ring opening hydrolase, encoded by the bamA gene, is especially useful because, in contrast to the benzoyl-CoA reductase, it is detected under a number of respiratory settings, including denitrifying, iron-reducing, sulfate-reducing, and fermentative conditions, and has a wide distribution in the environment. This review examines the bamA gene in enrichment cultures and environmental DNA extracts to consider whether it can be used as a biomarker for anaerobic aromatic degradation. Given the number of potential upstream inputs from natural and man-made monoaromatic compounds, the benzoyl-CoA pathway and the bamA gene in particular may play an important role in the global carbon cycle that has thus far been overlooked.
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Affiliation(s)
- Abigail W Porter
- Department of Environmental Science, School of Biological and Environmental Sciences, Rutgers University, New Brunswick, New Jersey, USA.
| | - Lily Y Young
- Department of Environmental Science, School of Biological and Environmental Sciences, Rutgers University, New Brunswick, New Jersey, USA
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Siegert M, Yates M, Call DF, Zhu X, Spormann A, Logan BE. Comparison of Nonprecious Metal Cathode Materials for Methane Production by Electromethanogenesis. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2014; 2:910-917. [PMID: 24741468 PMCID: PMC3982937 DOI: 10.1021/sc400520x] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/23/2014] [Indexed: 05/12/2023]
Abstract
In methanogenic microbial electrolysis cells (MMCs), CO2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials: plain graphite blocks, graphite blocks coated with carbon black or carbon black containing metals (platinum, stainless steel or nickel) or insoluble minerals (ferrihydrite, magnetite, iron sulfide, or molybdenum disulfide), and carbon fiber brushes. Assuming a stoichiometric ratio of hydrogen (abiotic):methane (biotic) of 4:1, methane production with platinum could be explained solely by hydrogen production. For most other materials, however, abiotic hydrogen production rates were insufficient to explain methane production. At -600 mV, platinum on carbon black had the highest abiotic hydrogen gas formation rate (1600 ± 200 nmol cm-3 d-1) and the highest biotic methane production rate (250 ± 90 nmol cm-3 d-1). At -550 mV, plain graphite (76 nmol cm-3 d-1) performed similarly to platinum (73 nmol cm-3 d-1). Coulombic recoveries, based on the measured current and evolved gas, were initially greater than 100% for all materials except platinum, suggesting that cathodic corrosion also contributed to electromethanogenic gas production.
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Affiliation(s)
- Michael Siegert
- Department
of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Matthew
D. Yates
- Department
of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Douglas F. Call
- Department
of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department
of Civil and Environmental Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Xiuping Zhu
- Department
of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alfred Spormann
- Department
of Civil and Environmental Engineering and Department of Chemical Engineering, Stanford
University, Stanford, California 94305, United States
| | - Bruce E. Logan
- Department
of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- E-mail: . Phone: +1 814-863-7908. Fax: +1 814-863-7304
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Pushie MJ, Cotelesage JJ, George GN. Molybdenum and tungsten oxygen transferases – structural and functional diversity within a common active site motif. Metallomics 2014; 6:15-24. [DOI: 10.1039/c3mt00177f] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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