1
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Sutherland‐Smith AJ, Carbone V, Schofield LR, Cronin B, Duin EC, Ronimus RS. The crystal structure of methanogen McrD, a methyl-coenzyme M reductase-associated protein. FEBS Open Bio 2024; 14:1222-1229. [PMID: 38877345 PMCID: PMC11301259 DOI: 10.1002/2211-5463.13848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 05/16/2024] [Accepted: 06/06/2024] [Indexed: 06/16/2024] Open
Abstract
Methyl-coenzyme M reductase (MCR) is a multi-subunit (α2β2γ2) enzyme responsible for methane formation via its unique F430 cofactor. The genes responsible for producing MCR (mcrA, mcrB and mcrG) are typically colocated with two other highly conserved genes mcrC and mcrD. We present here the high-resolution crystal structure for McrD from a human gut methanogen Methanomassiliicoccus luminyensis strain B10. The structure reveals that McrD comprises a ferredoxin-like domain assembled into an α + β barrel-like dimer with conformational flexibility exhibited by a functional loop. The description of the M. luminyensis McrD crystal structure contributes to our understanding of this key conserved methanogen protein typically responsible for promoting MCR activity and the production of methane, a greenhouse gas.
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Affiliation(s)
| | | | | | - Bryan Cronin
- Department of Chemistry and BiochemistryAuburn UniversityALUSA
| | - Evert C. Duin
- Department of Chemistry and BiochemistryAuburn UniversityALUSA
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2
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Byerly-Duke J, VanVeller B. Thioimidate Solutions to Thioamide Problems during Thionopeptide Deprotection. Org Lett 2024; 26:1452-1457. [PMID: 38341867 PMCID: PMC11031844 DOI: 10.1021/acs.orglett.4c00035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2024]
Abstract
Thioamides have structural and chemical similarity to peptide bonds, offering valuable insights when probing peptide backbone interactions, but are prone to side reactions during solid-phase peptide synthesis (SPPS). Thioimidates have been demonstrated to be effective protecting groups for thioamides during peptide elongation. We further demonstrate how thioimidates can assist thioamides through the most yield-crippling step of thionopeptide deprotection, allowing for the first isolation of an important benchmark α-helical peptide that had previously eluded synthesis and isolation.
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Affiliation(s)
- Jacob Byerly-Duke
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Brett VanVeller
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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3
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Gagsteiger J, Jahn S, Heidinger L, Gericke L, Andexer JN, Friedrich T, Loenarz C, Layer G. A Cobalamin-Dependent Radical SAM Enzyme Catalyzes the Unique C α -Methylation of Glutamine in Methyl-Coenzyme M Reductase. Angew Chem Int Ed Engl 2022; 61:e202204198. [PMID: 35638156 PMCID: PMC9401015 DOI: 10.1002/anie.202204198] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Indexed: 12/22/2022]
Abstract
Methyl‐coenzyme M reductase, which is responsible for the production of the greenhouse gas methane during biological methane formation, carries several unique posttranslational amino acid modifications, including a 2‐(S)‐methylglutamine. The enzyme responsible for the Cα‐methylation of this glutamine is not known. Herein, we identify and characterize a cobalamin‐dependent radical SAM enzyme as the glutamine C‐methyltransferase. The recombinant protein from Methanoculleus thermophilus binds cobalamin in a base‐off, His‐off conformation and contains a single [4Fe‐4S] cluster. The cobalamin cofactor cycles between the methyl‐cob(III)alamin, cob(II)alamin and cob(I)alamin states during catalysis and produces methylated substrate, 5′‐deoxyadenosine and S‐adenosyl‐l‐homocysteine in a 1 : 1 : 1 ratio. The newly identified glutamine C‐methyltransferase belongs to the class B radical SAM methyltransferases known to catalyze challenging methylation reactions of sp3‐hybridized carbon atoms.
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Affiliation(s)
- Jana Gagsteiger
- Institut für Pharmazeutische Wissenschaften, Pharmazeutische Biologie, Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Str. 19, 79104, Freiburg, Germany
| | - Sören Jahn
- Institut für Pharmazeutische Wissenschaften, Pharmazeutische und Medizinische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 25, 79104, Freiburg, Germany
| | - Lorenz Heidinger
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Lukas Gericke
- Institut für Pharmazeutische Wissenschaften, Pharmazeutische und Medizinische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 25, 79104, Freiburg, Germany
| | - Jennifer N Andexer
- Institut für Pharmazeutische Wissenschaften, Pharmazeutische und Medizinische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 25, 79104, Freiburg, Germany
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Christoph Loenarz
- Institut für Pharmazeutische Wissenschaften, Pharmazeutische und Medizinische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 25, 79104, Freiburg, Germany
| | - Gunhild Layer
- Institut für Pharmazeutische Wissenschaften, Pharmazeutische Biologie, Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Str. 19, 79104, Freiburg, Germany
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4
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Gagsteiger J, Jahn S, Heidinger L, Gericke L, Andexer JN, Friedrich T, Loenarz C, Layer G. A Cobalamin‐Dependent Radical SAM Enzyme Catalyzes the Unique Cα‐Methylation of Glutamine in Methyl‐Coenzyme M Reductase. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202204198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jana Gagsteiger
- Albert-Ludwigs-Universität Freiburg, Fakultät für Chemie und Pharmazie Institut für Pharmazeutische Wissenschaften, Pharmazeutische Biologie GERMANY
| | - Sören Jahn
- Albert-Ludwigs-Universität Freiburg, Fakultät für Chemie und Pharmazie Institut für Pharmazeutische Wissenschaften, Pharmazeutische und Medizinische Chemie GERMANY
| | - Lorenz Heidinger
- Albert-Ludwigs-Universität Freiburg Institut für Biochemie GERMANY
| | - Lukas Gericke
- Albert-Ludwigs-Universität Freiburg, Fakultät für Chemie und Pharmazie Institut für Pharmazeutische Wissenschaften, Pharmazeutische und Medizinische Chemie GERMANY
| | - Jennifer N. Andexer
- Albert-Ludwigs-Universität Freiburg, Fakultät für Chemie und Pharmazie Institut für Pharmazeutische Wissenschaften, Pharmazeutische und Medizinische Chemie GERMANY
| | - Thorsten Friedrich
- Albert-Ludwigs-Universität Freiburg, Fakultät für Chemie und Pharmazie Institut für Biochemie GERMANY
| | - Christoph Loenarz
- Albert-Ludwigs-Universität Freiburg, Fakultät für Chemie und Pharmazie Institut für Pharmazeutische Wissenschaften, Pharmazeutische und Medizinische Chemie GERMANY
| | - Gunhild Layer
- Albert-Ludwigs-Universität Freiburg, Fakultät für Chemie und Pharmazie Institut für Pharmazeutische Wissenschaften, Pharmazeutische Biologie Stefan-Meier-Str. 19 79104 Freiburg GERMANY
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5
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Lemaire O, Wagner T. A Structural View of Alkyl-Coenzyme M Reductases, the First Step of Alkane Anaerobic Oxidation Catalyzed by Archaea. Biochemistry 2022; 61:805-821. [PMID: 35500274 PMCID: PMC9118554 DOI: 10.1021/acs.biochem.2c00135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/14/2022] [Indexed: 11/28/2022]
Abstract
Microbial anaerobic oxidation of alkanes intrigues the scientific community by way of its impact on the global carbon cycle, and its biotechnological applications. Archaea are proposed to degrade short- and long-chain alkanes to CO2 by reversing methanogenesis, a theoretically reversible process. The pathway would start with alkane activation, an endergonic step catalyzed by methyl-coenzyme M reductase (MCR) homologues that would generate alkyl-thiols carried by coenzyme M. While the methane-generating MCR found in methanogens has been well characterized, the enzymatic activity of the putative alkane-fixing counterparts has not been validated so far. Such an absence of biochemical investigations contrasts with the current explosion of metagenomics data, which draws new potential alkane-oxidizing pathways in various archaeal phyla. Therefore, validating the physiological function of these putative alkane-fixing machines and investigating how their structures, catalytic mechanisms, and cofactors vary depending on the targeted alkane have become urgent needs. The first structural insights into the methane- and ethane-capturing MCRs highlighted unsuspected differences and proposed some explanations for their substrate specificity. This Perspective reviews the current physiological, biochemical, and structural knowledge of alkyl-CoM reductases and offers fresh ideas about the expected mechanistic and chemical differences among members of this broad family. We conclude with the challenges of the investigation of these particular enzymes, which might one day generate biofuels for our modern society.
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Affiliation(s)
- Olivier
N. Lemaire
- Max Planck Institute for
Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany
| | - Tristan Wagner
- Max Planck Institute for
Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany
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6
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Gendron A, Allen KD. Overview of Diverse Methyl/Alkyl-Coenzyme M Reductases and Considerations for Their Potential Heterologous Expression. Front Microbiol 2022; 13:867342. [PMID: 35547147 PMCID: PMC9081873 DOI: 10.3389/fmicb.2022.867342] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/01/2022] [Indexed: 12/02/2022] Open
Abstract
Methyl-coenzyme M reductase (MCR) is an archaeal enzyme that catalyzes the final step of methanogenesis and the first step in the anaerobic oxidation of methane, the energy metabolisms of methanogens and anaerobic methanotrophs (ANME), respectively. Variants of MCR, known as alkyl-coenzyme M reductases, are involved in the anaerobic oxidation of short-chain alkanes including ethane, propane, and butane as well as the catabolism of long-chain alkanes from oil reservoirs. MCR is a dimer of heterotrimers (encoded by mcrABG) and requires the nickel-containing tetrapyrrole prosthetic group known as coenzyme F430. MCR houses a series of unusual post-translational modifications within its active site whose identities vary depending on the organism and whose functions remain unclear. Methanogenic MCRs are encoded in a highly conserved mcrBDCGA gene cluster, which encodes two accessory proteins, McrD and McrC, that are believed to be involved in the assembly and activation of MCR, respectively. The requirement of a unique and complex coenzyme, various unusual post-translational modifications, and many remaining questions surrounding assembly and activation of MCR largely limit in vitro experiments to native enzymes with recombinant methods only recently appearing. Production of MCRs in a heterologous host is an important step toward developing optimized biocatalytic systems for methane production as well as for bioconversion of methane and other alkanes into value-added compounds. This review will first summarize MCR catalysis and structure, followed by a discussion of advances and challenges related to the production of diverse MCRs in a heterologous host.
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Affiliation(s)
| | - Kylie D. Allen
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
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7
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Crystallographic snapshots of a B 12-dependent radical SAM methyltransferase. Nature 2022; 602:336-342. [PMID: 35110733 PMCID: PMC8828468 DOI: 10.1038/s41586-021-04355-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 12/15/2021] [Indexed: 01/01/2023]
Abstract
By catalysing the microbial formation of methane, methyl-coenzyme M reductase has a central role in the global levels of this greenhouse gas1,2. The activity of methyl-coenzyme M reductase is profoundly affected by several unique post-translational modifications3–6, such as a unique C-methylation reaction catalysed by methanogenesis marker protein 10 (Mmp10), a radical S-adenosyl-l-methionine (SAM) enzyme7,8. Here we report the spectroscopic investigation and atomic resolution structure of Mmp10 from Methanosarcina acetivorans, a unique B12 (cobalamin)-dependent radical SAM enzyme9. The structure of Mmp10 reveals a unique enzyme architecture with four metallic centres and critical structural features involved in the control of catalysis. In addition, the structure of the enzyme–substrate complex offers a glimpse into a B12-dependent radical SAM enzyme in a precatalytic state. By combining electron paramagnetic resonance spectroscopy, structural biology and biochemistry, our study illuminates the mechanism by which the emerging superfamily of B12-dependent radical SAM enzymes catalyse chemically challenging alkylation reactions and identifies distinctive active site rearrangements to provide a structural rationale for the dual use of the SAM cofactor for radical and nucleophilic chemistry. Structural and spectroscopic studies show how a B12-dependent radical SAM enzyme catalyses unique and challenging alkylation chemistry, including protein post-translational modification required for methane biosynthesis.
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8
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Lampkin BJ, VanVeller B. Hydrogen Bond and Geometry Effects of Thioamide Backbone Modifications. J Org Chem 2021; 86:18287-18291. [PMID: 34851645 DOI: 10.1021/acs.joc.1c02373] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Thioamide substitution of backbone peptide bonds can probe interactions along the main chain of proteins. Despite theoretical predictions of the enhanced hydrogen bonding propensities of thioamides, previous studies often do not consider the geometric constraints imposed by folded peptide secondary structure. This work addresses drawbacks in previous studies that ignored the geometry dependence and local dielectric properties of thioamide hydrogen bonding and identifies cases where thioamides may be either stronger or weaker hydrogen-bonding partners than amides.
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Affiliation(s)
- Bryan J Lampkin
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Brett VanVeller
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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9
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Liu A, Krushnamurthy PH, Subramanya KS, Mitchell DA, Mahanta N. Enzymatic thioamidation of peptide backbones. Methods Enzymol 2021; 656:459-494. [PMID: 34325795 DOI: 10.1016/bs.mie.2021.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Thioamides are found in a few natural products and two known protein assemblies: the Escherichia coli ribosome and methyl-coenzyme M reductase (MCR) from methane-metabolizing archaea. Compared to an amide, thioamides alter the physical and chemical properties of peptide backbones, including the conformation dynamics, proteolytic stability, hydrogen-bonding capabilities, and possibly reactivity of a protein when installed. Recently, there has been significant progress in elucidating enzymatic post-translational thioamide installation, with most work leveraging the archaeal MCR-modifying enzymes. This chapter describes the protocols used for the in vitro enzymatic thioamidation of MCR-derived peptides, including polypeptide overexpression, purification, reaction reconstitution, and mass spectrometry-based product analysis. In addition, we highlight the protocols used for the biochemical, kinetics, and binding studies using recombinant enzymes obtained heterologously from E. coli. We anticipate that these methods will serve to guide future studies on peptide post-translational thioamidation, as well as other peptide backbone modifications using a parallel workflow.
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Affiliation(s)
- Andi Liu
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, United States; Department of Microbiology, University of Illinois, Urbana, IL, United States
| | - P H Krushnamurthy
- Department of Chemistry, Indian Institute of Technology Dharwad, Dharwad, Karnataka, India
| | - K S Subramanya
- Department of Chemistry, Indian Institute of Technology Dharwad, Dharwad, Karnataka, India
| | - Douglas A Mitchell
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, United States; Department of Microbiology, University of Illinois, Urbana, IL, United States; Department of Chemistry, University of Illinois, Urbana, IL, United States
| | - Nilkamal Mahanta
- Department of Chemistry, Indian Institute of Technology Dharwad, Dharwad, Karnataka, India.
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10
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Fiore KE, Phan HAT, Robkis DM, Walters CR, Petersson EJ. Incorporating thioamides into proteins by native chemical ligation. Methods Enzymol 2021; 656:295-339. [PMID: 34325791 PMCID: PMC8617429 DOI: 10.1016/bs.mie.2021.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The thioamide is a versatile replacement of the peptide backbone with altered hydrogen bonding and conformational preferences, as well the ability participate in energy and electron transfer processes. Semi-synthetic incorporation of a thioamide into a protein can be used to study protein folding or protein/protein interactions using these properties. Semi-synthesis also provides the opportunity to study the role of thioamides in natural proteins. Here we outline the semi-synthesis of a model protein, the B1 domain of protein G (GB1) with a thioamide at the N-terminus or the C-terminus. The thioamide is synthetically incorporated into a fragment by solid-phase peptide synthesis, whereas the remainder of the protein is recombinantly expressed. Then, the two fragments are joined by native chemical ligation. The explicit protocol for GB1 synthesis is accompanied by examples of applications with GB1 and other proteins in structural biology and protein misfolding studies.
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Affiliation(s)
- Kristen E Fiore
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States
| | - Hoang Anh T Phan
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States
| | - D Miklos Robkis
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States; Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania, Philadelphia, PA, United States
| | - Christopher R Walters
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States
| | - E James Petersson
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States.
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11
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Liu A, Si Y, Dong SH, Mahanta N, Penkala HN, Nair SK, Mitchell DA. Functional elucidation of TfuA in peptide backbone thioamidation. Nat Chem Biol 2021; 17:585-592. [PMID: 33707784 PMCID: PMC8084935 DOI: 10.1038/s41589-021-00771-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 02/11/2021] [Indexed: 01/31/2023]
Abstract
YcaO enzymes catalyze several post-translational modifications on peptide substrates, including thioamidation, which substitutes an amide oxygen with sulfur. Most predicted thioamide-forming YcaO enzymes are encoded adjacent to TfuA, which when present, is required for thioamidation. While activation of the peptide amide backbone is well established for YcaO enzymes, the function of TfuA has remained enigmatic. Here we characterize the TfuA protein involved in methyl-coenzyme M reductase thioamidation and demonstrate that TfuA catalyzes the hydrolysis of thiocarboxylated ThiS (ThiS-COSH), a proteinaceous sulfur donor, and enhances the affinity of YcaO toward the thioamidation substrate. We also report a crystal structure of a TfuA, which displays a new protein fold. Our structural and mutational analyses of TfuA have uncovered conserved binding interfaces with YcaO and ThiS in addition to revealing a hydrolase-like active site featuring a Ser-Lys catalytic pair.
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Affiliation(s)
- Andi Liu
- Department of Microbiology, University of Illinois, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
| | - Yuanyuan Si
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
- Department of Chemistry, University of Illinois, Urbana, IL, USA
| | - Shi-Hui Dong
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, China
| | - Nilkamal Mahanta
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
- Department of Chemistry, University of Illinois, Urbana, IL, USA
- Department of Chemistry, Indian Institute of Technology Dharwad, Karnataka, India
| | - Haley N Penkala
- Department of Microbiology, University of Illinois, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
| | - Satish K Nair
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA
- Department of Chemistry, University of Illinois, Urbana, IL, USA
- Department of Biochemistry, University of Illinois, Urbana, IL, USA
| | - Douglas A Mitchell
- Department of Microbiology, University of Illinois, Urbana, IL, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, USA.
- Department of Chemistry, University of Illinois, Urbana, IL, USA.
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12
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Structural Insights into the Methane-Generating Enzyme from a Methoxydotrophic Methanogen Reveal a Restrained Gallery of Post-Translational Modifications. Microorganisms 2021; 9:microorganisms9040837. [PMID: 33919946 PMCID: PMC8070964 DOI: 10.3390/microorganisms9040837] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/24/2021] [Accepted: 04/10/2021] [Indexed: 11/24/2022] Open
Abstract
Methanogenic archaea operate an ancient, if not primordial, metabolic pathway that releases methane as an end-product. This last step is orchestrated by the methyl-coenzyme M reductase (MCR), which uses a nickel-containing F430-cofactor as the catalyst. MCR astounds the scientific world by its unique reaction chemistry, its numerous post-translational modifications, and its importance in biotechnology not only for production but also for capturing the greenhouse gas methane. In this report, we investigated MCR natively isolated from Methermicoccus shengliensis. This methanogen was isolated from a high-temperature oil reservoir and has recently been shown to convert lignin and coal derivatives into methane through a process called methoxydotrophic methanogenesis. A methoxydotrophic culture was obtained by growing M. shengliensis with 3,4,5-trimethoxybenzoate as the main carbon and energy source. Under these conditions, MCR represents more than 12% of the total protein content. The native MCR structure refined at a resolution of 1.6-Å precisely depicts the organization of a dimer of heterotrimers. Despite subtle surface remodeling and complete conservation of its active site with other homologues, MCR from the thermophile M. shengliensis contains the most limited number of post-translational modifications reported so far, questioning their physiological relevance in other relatives.
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13
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Chen H, Gan Q, Fan C. Methyl-Coenzyme M Reductase and Its Post-translational Modifications. Front Microbiol 2020; 11:578356. [PMID: 33162960 PMCID: PMC7581889 DOI: 10.3389/fmicb.2020.578356] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/11/2020] [Indexed: 11/13/2022] Open
Abstract
The methyl-coenzyme M reductase (MCR) is a central enzyme in anaerobic microbial methane metabolism, which consists of methanogenesis and anaerobic oxidation of methane (AOM). MCR catalyzes the final step of methanogenesis and the first step of AOM to achieve the production and oxidation of methane, respectively. Besides a unique nickel tetrahydrocorphinoid (coenzyme F430), MCR also features several unusual post-translational modifications (PTMs), which are assumed to play important roles in regulating MCR functions. However, only few studies have been implemented on MCR PTMs. Therefore, to recapitulate current knowledge and prospect future studies, this review summarizes and discusses studies on MCR and its PTMs.
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Affiliation(s)
- Hao Chen
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
| | - Qinglei Gan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Chenguang Fan
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States.,Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
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14
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Shima S, Huang G, Wagner T, Ermler U. Structural Basis of Hydrogenotrophic Methanogenesis. Annu Rev Microbiol 2020; 74:713-733. [DOI: 10.1146/annurev-micro-011720-122807] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most methanogenic archaea use the rudimentary hydrogenotrophic pathway—from CO2and H2to methane—as the terminal step of microbial biomass degradation in anoxic habitats. The barely exergonic process that just conserves sufficient energy for a modest lifestyle involves chemically challenging reactions catalyzed by complex enzyme machineries with unique metal-containing cofactors. The basic strategy of the methanogenic energy metabolism is to covalently bind C1species to the C1carriers methanofuran, tetrahydromethanopterin, and coenzyme M at different oxidation states. The four reduction reactions from CO2to methane involve one molybdopterin-based two-electron reduction, two coenzyme F420–based hydride transfers, and one coenzyme F430–based radical process. For energy conservation, one ion-gradient-forming methyl transfer reaction is sufficient, albeit supported by a sophisticated energy-coupling process termed flavin-based electron bifurcation for driving the endergonic CO2reduction and fixation. Here, we review the knowledge about the structure-based catalytic mechanism of each enzyme of hydrogenotrophic methanogenesis.
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Affiliation(s)
- Seigo Shima
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Gangfeng Huang
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Tristan Wagner
- Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - Ulrich Ermler
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
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15
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Ferry JG. Methanosarcina acetivorans: A Model for Mechanistic Understanding of Aceticlastic and Reverse Methanogenesis. Front Microbiol 2020; 11:1806. [PMID: 32849414 PMCID: PMC7399021 DOI: 10.3389/fmicb.2020.01806] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/09/2020] [Indexed: 11/13/2022] Open
Abstract
Acetate-utilizing methanogens are responsible for approximately two-thirds of the one billion metric tons of methane produced annually in Earth's anaerobic environments. Methanosarcina acetivorans has emerged as a model organism for the mechanistic understanding of aceticlastic methanogenesis and reverse methanogenesis applicable to understanding the methane and carbon cycles in nature. It has the largest genome in the Archaea, supporting a metabolic complexity that enables a remarkable ability for adapting to environmental opportunities and challenges. Biochemical investigations have revealed an aceticlastic pathway capable of fermentative and respiratory energy conservation that explains how Ms. acetivorans is able to grow and compete in the environment. The mechanism of respiratory energy conservation also plays a role in overcoming endothermic reactions that are key to reversing methanogenesis.
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Affiliation(s)
- James G Ferry
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, United States
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16
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Nayak DD, Liu A, Agrawal N, Rodriguez-Carerro R, Dong SH, Mitchell DA, Nair SK, Metcalf WW. Functional interactions between posttranslationally modified amino acids of methyl-coenzyme M reductase in Methanosarcina acetivorans. PLoS Biol 2020; 18:e3000507. [PMID: 32092071 PMCID: PMC7058361 DOI: 10.1371/journal.pbio.3000507] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 03/05/2020] [Accepted: 02/04/2020] [Indexed: 01/27/2023] Open
Abstract
The enzyme methyl-coenzyme M reductase (MCR) plays an important role in mediating global levels of methane by catalyzing a reversible reaction that leads to the production or consumption of this potent greenhouse gas in methanogenic and methanotrophic archaea. In methanogenic archaea, the alpha subunit of MCR (McrA) typically contains four to six posttranslationally modified amino acids near the active site. Recent studies have identified enzymes performing two of these modifications (thioglycine and 5-[S]-methylarginine), yet little is known about the formation and function of the remaining posttranslationally modified residues. Here, we provide in vivo evidence that a dedicated S-adenosylmethionine-dependent methyltransferase encoded by a gene we designated methylcysteine modification (mcmA) is responsible for formation of S-methylcysteine in Methanosarcina acetivorans McrA. Phenotypic analysis of mutants incapable of cysteine methylation suggests that the S-methylcysteine residue might play a role in adaption to mesophilic conditions. To examine the interactions between the S-methylcysteine residue and the previously characterized thioglycine, 5-(S)-methylarginine modifications, we generated M. acetivorans mutants lacking the three known modification genes in all possible combinations. Phenotypic analyses revealed complex, physiologically relevant interactions between the modified residues, which alter the thermal stability of MCR in a combinatorial fashion that is not readily predictable from the phenotypes of single mutants. High-resolution crystal structures of inactive MCR lacking the modified amino acids were indistinguishable from the fully modified enzyme, suggesting that interactions between the posttranslationally modified residues do not exert a major influence on the static structure of the enzyme but rather serve to fine-tune the activity and efficiency of MCR.
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Affiliation(s)
- Dipti D. Nayak
- Carl R. Woese Institute of Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
| | - Andi Liu
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
| | - Neha Agrawal
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Roy Rodriguez-Carerro
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
| | - Shi-Hui Dong
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Douglas A. Mitchell
- Carl R. Woese Institute of Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois, Urbana, Illinois, United States of America
- Center for Biophysics & Quantitative Biology, University of Illinois, Urbana, Illinois, United States of America
| | - William W. Metcalf
- Carl R. Woese Institute of Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
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17
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Posttranslational Methylation of Arginine in Methyl Coenzyme M Reductase Has a Profound Impact on both Methanogenesis and Growth of Methanococcus maripaludis. J Bacteriol 2020; 202:JB.00654-19. [PMID: 31740491 DOI: 10.1128/jb.00654-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 11/09/2019] [Indexed: 02/05/2023] Open
Abstract
Catalyzing the key step for anaerobic production and/or oxidation of methane and likely other short-chain alkanes, methyl coenzyme M reductase (Mcr) and its homologs play a key role in the global carbon cycle. The McrA subunit possesses up to five conserved posttranslational modifications (PTMs) at its active site. It was previously suggested that methanogenesis marker protein 10 (Mmp10) could play an important role in methanogenesis. To systematically examine its physiological role, mmpX (locus tag MMP1554), the gene encoding Mmp10 in Methanococcus maripaludis, was deleted with a new genetic tool, resulting in the complete loss of the 5-C-(S)-methylarginine PTM of residue 275 in the McrA subunit. When the ΔmmpX mutant was complemented with the wild-type gene expressed by either a strong or a weak promoter, methylation was fully restored. Compared to the parental strain, maximal rates of methane formation by whole cells were reduced by 40 to 60% in the ΔmmpX mutant. The reduction in activity was fully reversed by the complement with the strong promoter. Site-directed mutagenesis of mmpX resulted in a differential loss of arginine methylation among the mutants in vivo, suggesting that activities of Mmp10 directly modulated methylation. R275 was present in a highly conserved PXRR275(A/S)R(G/A) signature sequence in McrAs. The only other protein in M. maripaludis containing a similar sequence was not methylated, suggesting that Mmp10 is specific for McrA. In conclusion, Mmp10 modulates the methyl-Arg PTM on McrA in a highly specific manner, which has a profound impact on Mcr activity.IMPORTANCE Mcr is the key enzyme in methanogenesis and a promising candidate for bioengineering the conversion of methane to liquid fuel. Our knowledge of Mcr is still limited. In terms of complexity, uniqueness, and environmental importance, Mcr is more comparable to photosynthetic reaction centers than conventional enzymes. PTMs have long been hypothesized to play key roles in modulating Mcr activity. Here, we directly link the mmpX gene to the arginine PTM of Mcr, demonstrate its association with methanogenesis activity, and offer insights into its substrate specificity and putative cofactor binding sites. This is also the first time that a PTM of McrA has been shown to have a substantial impact on both methanogenesis and growth in the absence of additional stressors.
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18
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Native top-down mass spectrometry provides insights into the copper centers of membrane-bound methane monooxygenase. Nat Commun 2019; 10:2675. [PMID: 31209220 PMCID: PMC6572826 DOI: 10.1038/s41467-019-10590-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/15/2019] [Indexed: 01/12/2023] Open
Abstract
Aerobic methane oxidation is catalyzed by particulate methane monooxygenase (pMMO), a copper-dependent, membrane metalloenzyme composed of subunits PmoA, PmoB, and PmoC. Characterization of the copper active site has been limited by challenges in spectroscopic analysis stemming from the presence of multiple copper binding sites, effects of detergent solubilization on activity and crystal structures, and the lack of a heterologous expression system. Here we utilize nanodiscs coupled with native top-down mass spectrometry (nTDMS) to determine the copper stoichiometry in each pMMO subunit and to detect post-translational modifications (PTMs). These results indicate the presence of a mononuclear copper center in both PmoB and PmoC. pMMO-nanodisc complexes with a higher stoichiometry of copper-bound PmoC exhibit increased activity, suggesting that the PmoC copper site plays a role in methane oxidation activity. These results provide key insights into the pMMO copper centers and demonstrate the ability of nTDMS to characterize complex membrane-bound metalloenzymes.
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19
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Dong SH, Liu A, Mahanta N, Mitchell DA, Nair SK. Mechanistic Basis for Ribosomal Peptide Backbone Modifications. ACS CENTRAL SCIENCE 2019; 5:842-851. [PMID: 31139720 PMCID: PMC6535971 DOI: 10.1021/acscentsci.9b00124] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Indexed: 05/16/2023]
Abstract
YcaO enzymes are known to catalyze the ATP-dependent formation of azoline heterocycles, thioamides, and (macro)lactamidines on peptide substrates. These enzymes are found in multiple biosynthetic pathways, including those for several different classes of ribosomally synthesized and post-translationally modified peptides (RiPPs). However, there are major knowledge gaps in the mechanistic and structural underpinnings that govern each of the known YcaO-mediated modifications. Here, we present the first structure of any YcaO enzyme bound to its peptide substrate in the active site, specifically that from Methanocaldococcus jannaschii which is involved in the thioamidation of the α-subunit of methyl-coenzyme M reductase (McrA). The structural data are leveraged to identify and test the residues involved in substrate binding and catalysis by site-directed mutagenesis. We also show that thioamide-forming YcaOs can carry out the cyclodehydration of a related peptide substrate, which underscores the mechanistic conservation across the YcaO family and allows for the extrapolation of mechanistic details to azoline-forming YcaOs involved in RiPP biosynthesis. A bioinformatic survey of all YcaOs highlights the diverse sequence space in azoline-forming YcaOs and suggests their early divergence from a common ancestor. The data presented within provide a detailed molecular framework for understanding this family of enzymes, which reconcile several decades of prior data on RiPP cyclodehydratases. These studies also provide the foundational knowledge to impact our mechanistic understanding of additional RiPP biosynthetic classes.
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Affiliation(s)
- Shi-Hui Dong
- Department
of Biochemistry, Carl R. Woese Institute for Genomic Biology, Department of Microbiology, Department of Chemistry, and Center for Biophysics
and Quantitative Biology, University of
Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, United
States
| | - Andi Liu
- Department
of Biochemistry, Carl R. Woese Institute for Genomic Biology, Department of Microbiology, Department of Chemistry, and Center for Biophysics
and Quantitative Biology, University of
Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, United
States
| | - Nilkamal Mahanta
- Department
of Biochemistry, Carl R. Woese Institute for Genomic Biology, Department of Microbiology, Department of Chemistry, and Center for Biophysics
and Quantitative Biology, University of
Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, United
States
| | - Douglas A. Mitchell
- Department
of Biochemistry, Carl R. Woese Institute for Genomic Biology, Department of Microbiology, Department of Chemistry, and Center for Biophysics
and Quantitative Biology, University of
Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, United
States
| | - Satish K. Nair
- Department
of Biochemistry, Carl R. Woese Institute for Genomic Biology, Department of Microbiology, Department of Chemistry, and Center for Biophysics
and Quantitative Biology, University of
Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, United
States
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20
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Thauer RK. Methyl (Alkyl)-Coenzyme M Reductases: Nickel F-430-Containing Enzymes Involved in Anaerobic Methane Formation and in Anaerobic Oxidation of Methane or of Short Chain Alkanes. Biochemistry 2019; 58:5198-5220. [PMID: 30951290 PMCID: PMC6941323 DOI: 10.1021/acs.biochem.9b00164] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Methyl-coenzyme
M reductase (MCR) catalyzes the methane-forming
step in methanogenic archaea. The active enzyme harbors the nickel(I)
hydrocorphin coenzyme F-430 as a prosthetic group and catalyzes the
reversible reduction of methyl-coenzyme M (CH3–S-CoM)
with coenzyme B (HS-CoM) to methane and CoM-S–S-CoB. MCR is
also involved in anaerobic methane oxidation in reverse of methanogenesis
and most probably in the anaerobic oxidation of ethane, propane, and
butane. The challenging question is how the unreactive CH3–S thioether bond in methyl-coenzyme M and the even more unreactive
C–H bond in methane and the other hydrocarbons are anaerobically
cleaved. A key to the answer is the negative redox potential (Eo′) of the Ni(II)F-430/Ni(I)F-430 couple
below −600 mV and the radical nature of Ni(I)F-430. However,
the negative one-electron redox potential is also the Achilles heel
of MCR; it makes the nickel enzyme one of the most O2-sensitive
enzymes known to date. Even under physiological conditions, the Ni(I)
in MCR is oxidized to the Ni(II) or Ni(III) states, e.g., when in
the cells the redox potential (E′) of the
CoM-S–S-CoB/HS-CoM and HS-CoB couple (Eo′ = −140 mV) gets too high. Methanogens therefore
harbor an enzyme system for the reactivation of inactivated MCR in
an ATP-dependent reduction reaction. Purification of active MCR in
the Ni(I) oxidation state is very challenging and has been achieved
in only a few laboratories. This perspective reviews the function,
structure, and properties of MCR, what is known and not known about
the catalytic mechanism, how the inactive enzyme is reactivated, and
what remains to be discovered.
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Affiliation(s)
- Rudolf K Thauer
- Max Planck Institute for Terrestrial Microbiology , Karl-von-Frisch-Strasse 10 , Marburg 35043 , Germany
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21
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Wide diversity of methane and short-chain alkane metabolisms in uncultured archaea. Nat Microbiol 2019; 4:603-613. [PMID: 30833729 PMCID: PMC6453112 DOI: 10.1038/s41564-019-0363-3] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 01/07/2019] [Indexed: 12/29/2022]
Abstract
Methanogenesis is an ancient metabolism of key ecological relevance, with direct impact on the evolution of Earth’s climate. Recent results suggest that the diversity of methane metabolisms and their derivations have probably been vastly underestimated. Here, by probing thousands of publicly available metagenomes for homologues of methyl-coenzyme M reductase complex (MCR), we have obtained ten metagenome-assembled genomes (MAGs) belonging to potential methanogenic, anaerobic methanotrophic and short-chain alkane oxidizing archaea. Five of these MAGs represent under-sampled (e.g., Verstraetearchaeota, Methanonatronarchaeia, ANME-1) or previously genomically undescribed (ANME-2c) archaeal lineages. The remaining five MAGs correspond to lineages that are only distantly related to previously known methanogens and span the entire archaeal phylogeny. Comprehensive comparative annotation significantly expands the metabolic diversity and energy conservation systems of MCR-bearing archaea. It also suggests the potential existence of a yet uncharacterized type of methanogenesis linked to short-chain alkane/fatty acid oxidation in a previously undescribed class of archaea (‘Ca. Methanoliparia’). We redefine a common core of marker genes specific to methanogenic, anaerobic methanotrophic and short-chain alkane-oxidizing archaea, and propose a possible scenario for the evolutionary and functional transitions that led to the emergence of such metabolic diversity.
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22
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Mahanta N, Szantai-Kis DM, Petersson EJ, Mitchell DA. Biosynthesis and Chemical Applications of Thioamides. ACS Chem Biol 2019; 14:142-163. [PMID: 30698414 PMCID: PMC6404778 DOI: 10.1021/acschembio.8b01022] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Thioamidation as a posttranslational modification is exceptionally rare, with only a few reported natural products and exactly one known protein example (methyl-coenzyme M reductase from methane-metabolizing archaea). Recently, there has been significant progress in elucidating the biosynthesis and function of several thioamide-containing natural compounds. Separate developments in the chemical installation of thioamides into peptides and proteins have enabled cell biology and biophysical studies to advance the current understanding of natural thioamides. This review highlights the various strategies used by Nature to install thioamides in peptidic scaffolds and the potential functions of this rare but important modification. We also discuss synthetic methods used for the site-selective incorporation of thioamides into polypeptides with a brief discussion of the physicochemical implications. This account will serve as a foundation for the further study of thioamides in natural products and their various applications.
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Affiliation(s)
| | - D Miklos Szantai-Kis
- Department of Biochemistry and Molecular Biophysics, Perelman School of Medicine , University of Pennsylvania , 3700 Hamilton Walk , Philadelphia , Pennsylvania 19104 , United States
| | - E James Petersson
- Department of Biochemistry and Molecular Biophysics, Perelman School of Medicine , University of Pennsylvania , 3700 Hamilton Walk , Philadelphia , Pennsylvania 19104 , United States
- Department of Chemistry , University of Pennsylvania , 231 South 34th Street , Philadelphia , Pennsylvania 19104 , United States
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23
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Identification of a unique Radical SAM methyltransferase required for the sp 3-C-methylation of an arginine residue of methyl-coenzyme M reductase. Sci Rep 2018; 8:7404. [PMID: 29743535 PMCID: PMC5943407 DOI: 10.1038/s41598-018-25716-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/27/2018] [Indexed: 12/27/2022] Open
Abstract
The biological formation of methane (methanogenesis) is a globally important process, which is exploited in biogas technology, but also contributes to global warming through the release of a potent greenhouse gas into the atmosphere. The last and methane-releasing step of methanogenesis is catalysed by the enzyme methyl-coenzyme M reductase (MCR), which carries several exceptional posttranslational amino acid modifications. Among these, a 5-C-(S)-methylarginine is located close to the active site of the enzyme. Here, we show that a unique Radical S-adenosyl-L-methionine (SAM) methyltransferase is required for the methylation of the arginine residue. The gene encoding the methyltransferase is currently annotated as “methanogenesis marker 10” whose function was unknown until now. The deletion of the methyltransferase gene ma4551 in Methanosarcina acetivorans WWM1 leads to the production of an active MCR lacking the C-5-methylation of the respective arginine residue. The growth behaviour of the corresponding M. acetivorans mutant strain and the biophysical characterization of the isolated MCR indicate that the methylated arginine is important for MCR stability under stress conditions.
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Assembly of Methyl Coenzyme M Reductase in the Methanogenic Archaeon Methanococcus maripaludis. J Bacteriol 2018; 200:JB.00746-17. [PMID: 29339414 DOI: 10.1128/jb.00746-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 01/04/2018] [Indexed: 01/22/2023] Open
Abstract
Methyl coenzyme M reductase (MCR) is a complex enzyme that catalyzes the final step in biological methanogenesis. To better understand its assembly, the recombinant MCR from the thermophile Methanothermococcus okinawensis (rMCRok) was expressed in the mesophile Methanococcus maripaludis The rMCRok was posttranslationally modified correctly and contained McrD and the unique nickel tetrapyrrole coenzyme F430 Subunits of the native M. maripaludis (MCRmar) were largely absent, suggesting that the recombinant enzyme was formed by an assembly of cotranscribed subunits. Strong support for this hypothesis was obtained by expressing a chimeric operon comprising the His-tagged mcrA from M. maripaludis and the mcrBDCG from M. okinawensis in M. maripaludis The His-tagged purified rMCR then contained the M. maripaludis McrA and the M. okinawensis McrBDG. The present study prompted us to form a working model for MCR assembly, which can be further tested by the heterologous expression system established here.IMPORTANCE Approximately 1.6% of the net primary production of plants, algae, and cyanobacteria are processed by biological methane production in anoxic environments. This accounts for about 74% of the total global methane production, up to 25% of which is consumed by anaerobic oxidation of methane (AOM). Methyl coenzyme M reductase (MCR) is the key enzyme in both methanogenesis and AOM. MCR is assembled as a dimer of two heterotrimers, where posttranslational modifications and F430 cofactors are embedded in the active sites. However, this complex assembly process remains unknown. Here, we established a heterologous expression system for MCR to learn how MCR is assembled.
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25
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Abstract
Methyl-coenzyme M reductase (MCR) is an essential enzyme found strictly in methanogenic and methanotrophic archaea. MCR catalyzes a reversible reaction involved in the production and consumption of the potent greenhouse gas methane. The α-subunit of this enzyme (McrA) contains several unusual posttranslational modifications, including the only known naturally occurring example of protein thioamidation. We have recently demonstrated by genetic deletion and mass spectrometry that the tfuA and ycaO genes of Methanosarcina acetivorans are involved in thioamidation of Gly465 in the MCR active site. Modification to thioGly has been postulated to stabilize the active site structure of MCR. Herein, we report the in vitro reconstitution of ribosomal peptide thioamidation using heterologously expressed and purified YcaO and TfuA proteins from M. acetivorans Like other reported YcaO proteins, this reaction is ATP-dependent but requires an external sulfide source. We also reconstitute the thioamidation activity of two TfuA-independent YcaOs from the hyperthermophilic methanogenic archaea Methanopyrus kandleri and Methanocaldococcus jannaschii Using these proteins, we demonstrate the basis for substrate recognition and regioselectivity of thioamide formation based on extensive mutagenesis, biochemical, and binding studies. Finally, we report nucleotide-free and nucleotide-bound crystal structures for the YcaO proteins from M. kandleri Sequence and structure-guided mutagenesis with subsequent biochemical evaluation have allowed us to assign roles for residues involved in thioamidation and confirm that the reaction proceeds via backbone O-phosphorylation. These data assign a new biochemical reaction to the YcaO superfamily and paves the way for further characterization of additional peptide backbone posttranslational modifications.
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26
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Müller MM. Post-Translational Modifications of Protein Backbones: Unique Functions, Mechanisms, and Challenges. Biochemistry 2017; 57:177-185. [PMID: 29064683 PMCID: PMC5770884 DOI: 10.1021/acs.biochem.7b00861] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
Post-translational
modifications (PTMs) dramatically enhance the
capabilities of proteins. They introduce new functionalities and dynamically
control protein activity by modulating intra- and intermolecular interactions.
Traditionally, PTMs have been considered as reversible attachments
to nucleophilic functional groups on amino acid side chains, whereas
the polypeptide backbone is often thought to be inert. This paradigm
is shifting as chemically and functionally diverse alterations of
the protein backbone are discovered. Importantly, backbone PTMs can
control protein structure and function just as side chain modifications
do and operate through unique mechanisms to achieve these features.
In this Perspective, I outline the various types of protein backbone
modifications discovered so far and highlight their contributions
to biology as well as the challenges in studying this versatile yet
poorly characterized class of PTMs.
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Affiliation(s)
- Manuel M Müller
- Department of Chemistry, King's College London , 7 Trinity Street, London SE1 1DB, United Kingdom
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27
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Nayak DD, Mahanta N, Mitchell DA, Metcalf WW. Post-translational thioamidation of methyl-coenzyme M reductase, a key enzyme in methanogenic and methanotrophic Archaea. eLife 2017; 6. [PMID: 28880150 PMCID: PMC5589413 DOI: 10.7554/elife.29218] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/11/2017] [Indexed: 12/14/2022] Open
Abstract
Methyl-coenzyme M reductase (MCR), found in strictly anaerobic methanogenic and methanotrophic archaea, catalyzes the reversible production and consumption of the potent greenhouse gas methane. The α subunit of MCR (McrA) contains several unusual post-translational modifications, including a rare thioamidation of glycine. Based on the presumed function of homologous genes involved in the biosynthesis of thioviridamide, a thioamide-containing natural product, we hypothesized that the archaeal tfuA and ycaO genes would be responsible for post-translational installation of thioglycine into McrA. Mass spectrometric characterization of McrA from the methanogenic archaeon Methanosarcina acetivorans lacking tfuA and/or ycaO revealed the presence of glycine, rather than thioglycine, supporting this hypothesis. Phenotypic characterization of the ∆ycaO-tfuA mutant revealed a severe growth rate defect on substrates with low free energy yields and at elevated temperatures (39°C - 45°C). Our analyses support a role for thioglycine in stabilizing the protein secondary structure near the active site.
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Affiliation(s)
- Dipti D Nayak
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, United States
| | - Nilkamal Mahanta
- Department of Chemistry, University of Illinois, Urbana, United States
| | - Douglas A Mitchell
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, United States.,Department of Chemistry, University of Illinois, Urbana, United States.,Department of Microbiology, University of Illinois, Urbana, United States
| | - William W Metcalf
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, United States.,Department of Microbiology, University of Illinois, Urbana, United States
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28
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Phylogenetic and Structural Comparisons of the Three Types of Methyl Coenzyme M Reductase from Methanococcales and Methanobacteriales. J Bacteriol 2017; 199:JB.00197-17. [PMID: 28559298 DOI: 10.1128/jb.00197-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 05/17/2017] [Indexed: 01/08/2023] Open
Abstract
The phylogenetically diverse family of methanogenic archaea universally use methyl coenzyme M reductase (MCR) for catalyzing the final methane-forming reaction step of the methanogenic energy metabolism. Some methanogens of the orders Methanobacteriales and Methanococcales contain two isoenzymes. Comprehensive phylogenetic analyses on the basis of all three subunits grouped MCRs from Methanobacteriales and Methanococcales into three distinct types: (i) MCRs from Methanobacteriales, (ii) MCRs from Methanobacteriales and Methanococcales, and (iii) MCRs from Methanococcales The first and second types contain MCR isoenzymes I and II from Methanothermobacter marburgensis, respectively; therefore, they were designated MCR type I and type II and accordingly; the third one was designated MCR type III. For comparison with the known MCR type I and type II structures, we determined the structure of MCR type III from Methanotorris formicicus and Methanothermococcus thermolithotrophicus As predicted, the three MCR types revealed highly similar overall structures and virtually identical active site architectures reflecting the chemically challenging mechanism of methane formation. Pronounced differences were found at the protein surface with respect to loop geometries and electrostatic properties, which also involve the entrance of the active-site funnel. In addition, the C-terminal end of the γ-subunit is prolonged by an extra helix after helix γ8 in MCR type II and type III, which is, however, differently arranged in the two MCR types. MCR types I, II, and III share most of the posttranslational modifications which appear to fine-tune the enzymatic catalysis. Interestingly, MCR type III lacks the methyl-cysteine but possesses in subunit α of M. formicicus a 6-hydroxy-tryptophan, which thus far has been found only in the α-amanitin toxin peptide but not in proteins.IMPORTANCE Methyl coenzyme M reductase (MCR) represents a prime target for the mitigation of methane releases. Phylogenetic analyses of MCRs suggested several distinct sequence clusters; those from Methanobacteriales and Methanococcales were subdivided into three types: MCR type I from Methanobacteriales, MCR type II from Methanobacteriales and Methanococcales, and the newly designated MCR type III exclusively from Methanococcales We determined the first X-ray structures for an MCR type III. Detailed analyses revealed substantial differences between the three types only in the peripheral region. The subtle modifications identified and electrostatic profiles suggested enhanced substrate binding for MCR type III. In addition, MCR type III from Methanotorris formicicus contains 6-hydroxy-tryptophan, a new posttranslational modification that thus far has been found only in the α-amanitin toxin.
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Ragsdale SW, Raugei S, Ginovska B, Wongnate T. Biochemistry of Methyl-Coenzyme M Reductase. THE BIOLOGICAL CHEMISTRY OF NICKEL 2017. [DOI: 10.1039/9781788010580-00149] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Methanogens are masters of CO2 reduction. They conserve energy by coupling H2 oxidation to the reduction of CO2 to CH4, the primary constituent of natural gas. They also generate methane by the reduction of acetic acid, methanol, methane thiol, and methylamines. Methanogens produce 109 tons of methane per year and are the major source of the earth’s atmospheric methane. Reverse methanogenesis or anaerobic methane oxidation, which is catalyzed by methanotrophic archaea living in consortia among bacteria that can act as an electron acceptor, is responsible for annual oxidation of 108 tons of methane to CO2. This chapter briefly describes the overall process of methanogenesis and then describes the enzymatic mechanism of the nickel enzyme, methyl-CoM reductase (MCR), the key enzyme in methane synthesis and oxidation. MCR catalyzes the formation of methane and the heterodisulfide (CoBSSCoM) from methyl-coenzyme M (methyl-CoM) and coenzyme B (HSCoB). Uncovering the mechanistic and molecular details of MCR catalysis is critical since methane is an abundant and important fuel and is the second (to CO2) most prevalent greenhouse gas.
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Affiliation(s)
- Stephen W. Ragsdale
- Department of Biological Chemistry, University of Michigan Medical School 1150 W. Medical Center Dr., 5301 MSRB III Ann Arbor MI 48109-0606 USA
| | - Simone Raugei
- Physical Sciences Division, Pacific Northwest National Laboratory, Post Office Box 999 K1-83 Richland WA 99352 USA
| | - Bojana Ginovska
- Physical Sciences Division, Pacific Northwest National Laboratory, Post Office Box 999 K1-83 Richland WA 99352 USA
| | - Thanyaporn Wongnate
- School of Bioresources and Technology and Excellent Center of Waste Utilization and Management (ECoWaste), King Mongkut's University of Technology Thonburi Bangkhunthian, Bangkok 10140 Thailand
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Nayak DD, Metcalf WW. Cas9-mediated genome editing in the methanogenic archaeon Methanosarcina acetivorans. Proc Natl Acad Sci U S A 2017; 114:2976-2981. [PMID: 28265068 PMCID: PMC5358397 DOI: 10.1073/pnas.1618596114] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although Cas9-mediated genome editing has proven to be a powerful genetic tool in eukaryotes, its application in Bacteria has been limited because of inefficient targeting or repair; and its application to Archaea has yet to be reported. Here we describe the development of a Cas9-mediated genome-editing tool that allows facile genetic manipulation of the slow-growing methanogenic archaeon Methanosarcina acetivorans Introduction of both insertions and deletions by homology-directed repair was remarkably efficient and precise, occurring at a frequency of approximately 20% relative to the transformation efficiency, with the desired mutation being found in essentially all transformants examined. Off-target activity was not observed. We also observed that multiple single-guide RNAs could be expressed in the same transcript, reducing the size of mutagenic plasmids and simultaneously simplifying their design. Cas9-mediated genome editing reduces the time needed to construct mutants by more than half (3 vs. 8 wk) and allows simultaneous construction of double mutants with high efficiency, exponentially decreasing the time needed for complex strain constructions. Furthermore, coexpression the nonhomologous end-joining (NHEJ) machinery from the closely related archaeon, Methanocella paludicola, allowed efficient Cas9-mediated genome editing without the need for a repair template. The NHEJ-dependent mutations included deletions ranging from 75 to 2.7 kb in length, most of which appear to have occurred at regions of naturally occurring microhomology. The combination of homology-directed repair-dependent and NHEJ-dependent genome-editing tools comprises a powerful genetic system that enables facile insertion and deletion of genes, rational modification of gene expression, and testing of gene essentiality.
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Affiliation(s)
- Dipti D Nayak
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - William W Metcalf
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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Helf MJ, Jud A, Piel J. Enzyme from an Uncultivated Sponge Bacterium Catalyzes S-Methylation in a Ribosomal Peptide. Chembiochem 2017; 18:444-450. [DOI: 10.1002/cbic.201600594] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Maximilian J. Helf
- Institute of Microbiology; HCI G431; Eidgenössische Technische Hochschule (ETH) Zürich; Vladimir-Prelog-Weg 4 8093 Zürich Switzerland
- Boyce Thompson Institute; Cornell University; 533 Tower Road Ithaca NY 14850 USA
| | - Aurelia Jud
- Institute of Microbiology; HCI G431; Eidgenössische Technische Hochschule (ETH) Zürich; Vladimir-Prelog-Weg 4 8093 Zürich Switzerland
| | - Jörn Piel
- Institute of Microbiology; HCI G431; Eidgenössische Technische Hochschule (ETH) Zürich; Vladimir-Prelog-Weg 4 8093 Zürich Switzerland
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Lawton TJ, Rosenzweig AC. Methane-Oxidizing Enzymes: An Upstream Problem in Biological Gas-to-Liquids Conversion. J Am Chem Soc 2016; 138:9327-40. [PMID: 27366961 PMCID: PMC5242187 DOI: 10.1021/jacs.6b04568] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Biological conversion of natural gas to liquids (Bio-GTL) represents an immense economic opportunity. In nature, aerobic methanotrophic bacteria and anaerobic archaea are able to selectively oxidize methane using methane monooxygenase (MMO) and methyl coenzyme M reductase (MCR) enzymes. Although significant progress has been made toward genetically manipulating these organisms for biotechnological applications, the enzymes themselves are slow, complex, and not recombinantly tractable in traditional industrial hosts. With turnover numbers of 0.16-13 s(-1), these enzymes pose a considerable upstream problem in the biological production of fuels or chemicals from methane. Methane oxidation enzymes will need to be engineered to be faster to enable high volumetric productivities; however, efforts to do so and to engineer simpler enzymes have been minimally successful. Moreover, known methane-oxidizing enzymes have different expression levels, carbon and energy efficiencies, require auxiliary systems for biosynthesis and function, and vary considerably in terms of complexity and reductant requirements. The pros and cons of using each methane-oxidizing enzyme for Bio-GTL are considered in detail. The future for these enzymes is bright, but a renewed focus on studying them will be critical to the successful development of biological processes that utilize methane as a feedstock.
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Affiliation(s)
- Thomas J Lawton
- Departments of Molecular Biosciences and of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Amy C Rosenzweig
- Departments of Molecular Biosciences and of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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Abstract
Early parental influence led me first to medical school, but after developing a passion for biochemistry and sensing the need for a deeper foundation, I changed to chemistry. During breaks between semesters, I worked in various biochemistry labs to acquire a feeling for the different areas of investigation. The scientific puzzle that fascinated me most was the metabolism of the anaerobic bacterium Clostridium kluyveri, which I took on in 1965 in Karl Decker's lab in Freiburg, Germany. I quickly realized that little was known about the biochemistry of strict anaerobes such as clostridia, methanogens, acetogens, and sulfate-reducing bacteria and that these were ideal model organisms to study fundamental questions of energy conservation, CO2 fixation, and the evolution of metabolic pathways. My passion for anaerobes was born then and is unabated even after 50 years of study.
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Affiliation(s)
- Rudolf Kurt Thauer
- Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany;
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Evans PN, Parks DH, Chadwick GL, Robbins SJ, Orphan VJ, Golding SD, Tyson GW. Methane metabolism in the archaeal phylum Bathyarchaeota revealed by genome-centric metagenomics. Science 2016; 350:434-8. [PMID: 26494757 DOI: 10.1126/science.aac7745] [Citation(s) in RCA: 423] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Methanogenic and methanotrophic archaea play important roles in the global flux of methane. Culture-independent approaches are providing deeper insight into the diversity and evolution of methane-metabolizing microorganisms, but, until now, no compelling evidence has existed for methane metabolism in archaea outside the phylum Euryarchaeota. We performed metagenomic sequencing of a deep aquifer, recovering two near-complete genomes belonging to the archaeal phylum Bathyarchaeota (formerly known as the Miscellaneous Crenarchaeotal Group). These genomes contain divergent homologs of the genes necessary for methane metabolism, including those that encode the methyl-coenzyme M reductase (MCR) complex. Additional non-euryarchaeotal MCR-encoding genes identified in a range of environments suggest that unrecognized archaeal lineages may also contribute to global methane cycling. These findings indicate that methane metabolism arose before the last common ancestor of the Euryarchaeota and Bathyarchaeota.
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Affiliation(s)
- Paul N Evans
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Queensland, Australia
| | - Donovan H Parks
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Queensland, Australia
| | - Grayson L Chadwick
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Steven J Robbins
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Queensland, Australia
| | - Victoria J Orphan
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Suzanne D Golding
- School of Earth Sciences, University of Queensland, St Lucia 4072, Queensland, Australia
| | - Gene W Tyson
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Queensland, Australia. Advanced Water Management Centre, University of Queensland, St Lucia 4072, Queensland, Australia.
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Kang TJ, Lee EY. Metabolic versatility of microbial methane oxidation for biocatalytic methane conversion. J IND ENG CHEM 2016. [DOI: 10.1016/j.jiec.2016.01.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Leon DR, Ytterberg AJ, Boontheung P, Kim U, Loo JA, Gunsalus RP, Ogorzalek Loo RR. Mining proteomic data to expose protein modifications in Methanosarcina mazei strain Gö1. Front Microbiol 2015; 6:149. [PMID: 25798134 PMCID: PMC4350412 DOI: 10.3389/fmicb.2015.00149] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 02/09/2015] [Indexed: 12/11/2022] Open
Abstract
Proteomic tools identify constituents of complex mixtures, often delivering long lists of identified proteins. The high-throughput methods excel at matching tandem mass spectrometry data to spectra predicted from sequence databases. Unassigned mass spectra are ignored, but could, in principle, provide valuable information on unanticipated modifications and improve protein annotations while consuming limited quantities of material. Strategies to "mine" information from these discards are presented, along with discussion of features that, when present, provide strong support for modifications. In this study we mined LC-MS/MS datasets of proteolytically-digested concanavalin A pull down fractions from Methanosarcina mazei Gö1 cell lysates. Analyses identified 154 proteins. Many of the observed proteins displayed post-translationally modified forms, including O-formylated and methyl-esterified segments that appear biologically relevant (i.e., not artifacts of sample handling). Interesting cleavages and modifications (e.g., S-cyanylation and trimethylation) were observed near catalytic sites of methanogenesis enzymes. Of 31 Methanosarcina protein N-termini recovered by concanavalin A binding or from a previous study, only M. mazei S-layer protein MM1976 and its M. acetivorans C2A orthologue, MA0829, underwent signal peptide excision. Experimental results contrast with predictions from algorithms SignalP 3.0 and Exprot, which were found to over-predict the presence of signal peptides. Proteins MM0002, MM0716, MM1364, and MM1976 were found to be glycosylated, and employing chromatography tailored specifically for glycopeptides will likely reveal more. This study supplements limited, existing experimental datasets of mature archaeal N-termini, including presence or absence of signal peptides, translation initiation sites, and other processing. Methanosarcina surface and membrane proteins are richly modified.
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Affiliation(s)
- Deborah R Leon
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - A Jimmy Ytterberg
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - Pinmanee Boontheung
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - Unmi Kim
- Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles Los Angeles, CA, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA ; Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
| | - Robert P Gunsalus
- Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
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Alvarado A, Montañez-Hernández LE, Palacio-Molina SL, Oropeza-Navarro R, Luévanos-Escareño MP, Balagurusamy N. Microbial trophic interactions and mcrA gene expression in monitoring of anaerobic digesters. Front Microbiol 2014; 5:597. [PMID: 25429286 PMCID: PMC4228917 DOI: 10.3389/fmicb.2014.00597] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 10/22/2014] [Indexed: 11/13/2022] Open
Abstract
Anaerobic digestion (AD) is a biological process where different trophic groups of microorganisms break down biodegradable organic materials in the absence of oxygen. A wide range of AD technologies is being used to convert livestock manure, municipal and industrial wastewaters, and solid organic wastes into biogas. AD gains importance not only because of its relevance in waste treatment but also because of the recovery of carbon in the form of methane, which is a renewable energy and is used to generate electricity and heat. Despite the advances on the engineering and design of new bioreactors for AD, the microbiology component always poses challenges. Microbiology of AD processes is complicated as the efficiency of the process depends on the interactions of various trophic groups involved. Due to the complex interdependence of microbial activities for the functionality of the anaerobic bioreactors, the genetic expression of mcrA, which encodes a key enzyme in methane formation, is proposed as a parameter to monitor the process performance in real time. This review evaluates the current knowledge on microbial groups, their interactions, and their relationship to the performance of anaerobic biodigesters with a focus on using mcrA gene expression as a tool to monitor the process.
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Affiliation(s)
- Alejandra Alvarado
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, MarburgGermany
| | - Lilia E. Montañez-Hernández
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
| | - Sandra L. Palacio-Molina
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
| | | | - Miriam P. Luévanos-Escareño
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
| | - Nagamani Balagurusamy
- Laboratorio de Biorremediación, Escuela de Ciencias Biológicas, Universidad Autónoma de Coahuila, TorreónMéxico
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Petersson EJ, Goldberg JM, Wissner RF. On the use of thioamides as fluorescence quenching probes for tracking protein folding and stability. Phys Chem Chem Phys 2014; 16:6827-37. [PMID: 24598971 DOI: 10.1039/c3cp55525a] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Our laboratory has developed thioamide analogs of the natural amino acids as minimally-perturbing fluorescence quenching probes that can be placed at many locations in a protein sequence. We have shown that the mechanism of quenching can be either Förster resonance energy transfer (FRET) or photoinduced electron transfer (PET), depending on the identity of the donor fluorophore. Furthermore, we have shown that one can use a combination of semi-synthetic methods to label full-sized proteins with fluorophore-thioamide pairs. These probes can be used to study protein-protein interactions, protein folding or misfolding, and proteolysis.
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Affiliation(s)
- E James Petersson
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA.
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Biochemistry of methyl-coenzyme M reductase: the nickel metalloenzyme that catalyzes the final step in synthesis and the first step in anaerobic oxidation of the greenhouse gas methane. Met Ions Life Sci 2014; 14:125-45. [PMID: 25416393 DOI: 10.1007/978-94-017-9269-1_6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Methane, the major component of natural gas, has been in use in human civilization since ancient times as a source of fuel and light. Methanogens are responsible for synthesis of most of the methane found on Earth. The enzyme responsible for catalyzing the chemical step of methanogenesis is methyl-coenzyme M reductase (MCR), a nickel enzyme that contains a tetrapyrrole cofactor called coenzyme F430, which can traverse the Ni(I), (II), and (III) oxidation states. MCR and methanogens are also involved in anaerobic methane oxidation. This review describes structural, kinetic, and computational studies aimed at elucidating the mechanism of MCR. Such studies are expected to impact the many ramifications of methane in our society and environment, including energy production and greenhouse gas warming.
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Huang Y, Jahreis G, Fischer G, Lücke C. Atomic Polarizability Dominates the Electronic Properties of Peptide Bonds upon Thioxo or Selenoxo Substitution. Chemistry 2012; 18:9841-8. [DOI: 10.1002/chem.201200863] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Indexed: 11/08/2022]
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Shima S, Krueger M, Weinert T, Demmer U, Kahnt J, Thauer RK, Ermler U. Structure of a methyl-coenzyme M reductase from Black Sea mats that oxidize methane anaerobically. Nature 2011; 481:98-101. [DOI: 10.1038/nature10663] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 10/19/2011] [Indexed: 11/09/2022]
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More than 200 genes required for methane formation from H₂ and CO₂ and energy conservation are present in Methanothermobacter marburgensis and Methanothermobacter thermautotrophicus. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2011; 2011:973848. [PMID: 21559116 PMCID: PMC3087415 DOI: 10.1155/2011/973848] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 12/07/2010] [Accepted: 02/18/2011] [Indexed: 12/19/2022]
Abstract
The hydrogenotrophic methanogens Methanothermobacter marburgensis and Methanothermobacter thermautotrophicus can easily be mass cultured. They have therefore been used almost exclusively to study the biochemistry of methanogenesis from H2 and CO2, and the genomes of these two model organisms have been sequenced. The close relationship of the two organisms is reflected in their genomic architecture and coding potential. Within the 1,607 protein coding sequences (CDS) in common, we identified approximately 200 CDS required for the synthesis of the enzymes, coenzymes, and prosthetic groups involved in CO2 reduction to methane and in coupling this process with the phosphorylation of ADP. Approximately 20 additional genes, such as those for the biosynthesis of F430 and methanofuran and for the posttranslational modifications of the two methyl-coenzyme M reductases, remain to be identified.
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Kühn J, Briegel A, Mörschel E, Kahnt J, Leser K, Wick S, Jensen GJ, Thanbichler M. Bactofilins, a ubiquitous class of cytoskeletal proteins mediating polar localization of a cell wall synthase in Caulobacter crescentus. EMBO J 2009; 29:327-39. [PMID: 19959992 DOI: 10.1038/emboj.2009.358] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 10/26/2009] [Indexed: 01/03/2023] Open
Abstract
The cytoskeleton has a key function in the temporal and spatial organization of both prokaryotic and eukaryotic cells. Here, we report the identification of a new class of polymer-forming proteins, termed bactofilins, that are widely conserved among bacteria. In Caulobacter crescentus, two bactofilin paralogues cooperate to form a sheet-like structure lining the cytoplasmic membrane in proximity of the stalked cell pole. These assemblies mediate polar localization of a peptidoglycan synthase involved in stalk morphogenesis, thus complementing the function of the actin-like cytoskeleton and the cell division machinery in the regulation of cell wall biogenesis. In other bacteria, bactofilins can establish rod-shaped filaments or associate with the cell division apparatus, indicating considerable structural and functional flexibility. Bactofilins polymerize spontaneously in the absence of additional cofactors in vitro, forming stable ribbon- or rod-like filament bundles. Our results suggest that these structures have evolved as an alternative to intermediate filaments, serving as versatile molecular scaffolds in a variety of cellular pathways.
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Affiliation(s)
- Juliane Kühn
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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Correlation of methane production and functional gene transcriptional activity in a peat soil. Appl Environ Microbiol 2009; 75:6679-87. [PMID: 19749064 DOI: 10.1128/aem.01021-09] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription dynamics of subunit A of the key gene in methanogenesis (methyl coenzyme M reductase; mcrA) was studied to evaluate the relationship between process rate (methanogenesis) and gene transcription dynamics in a peat soil ecosystem. Soil methanogen process rates were determined during incubation of peat slurries at temperatures from 4 to 37 degrees C, and real-time quantitative PCR was applied to quantify the abundances of mcrA genes and transcripts; corresponding transcriptional dynamics were calculated from mcrA transcript/gene ratios. Internal standards suggested unbiased recovery of mRNA abundances in comparison to DNA levels. In comparison to those in pure-culture studies, mcrA transcript/gene ratios indicated underestimation by 1 order of magnitude, possibly due to high proportions of inactive or dead methanogens. Methane production rates were temperature dependent, with maxima at 25 degrees C, but changes in abundance and transcription of the mcrA gene showed no correlation with temperature. However, mcrA transcript/gene ratios correlated weakly (regression coefficient = 0.76) with rates of methanogenesis. Methanogen process rates increased over 3 orders of magnitude, while the corresponding maximum transcript/gene ratio increase was only 18-fold. mcrA transcript dynamics suggested steady-state expression in peat soil after incubation for 24 and 48 h, similar to that in stationary-phase cultures. mcrA transcript/gene ratios are therefore potential in situ indicators of methanogen process rate changes in complex soil systems.
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Mayr S, Latkoczy C, Krüger M, Günther D, Shima S, Thauer RK, Widdel F, Jaun B. Structure of an F430 Variant from Archaea Associated with Anaerobic Oxidation of Methane. J Am Chem Soc 2008; 130:10758-67. [DOI: 10.1021/ja802929z] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stefan Mayr
- Laboratory of Organic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
| | - Christopher Latkoczy
- Laboratory of Organic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
| | - Martin Krüger
- Laboratory of Organic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
| | - Detlef Günther
- Laboratory of Organic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
| | - Seigo Shima
- Laboratory of Organic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
| | - Rudolf K. Thauer
- Laboratory of Organic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
| | - Friedrich Widdel
- Laboratory of Organic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
| | - Bernhard Jaun
- Laboratory of Organic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland, Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, 35043 Marburg, Germany
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Zuther K, Mayser P, Hettwer U, Wu W, Spiteller P, Kindler BLJ, Karlovsky P, Basse CW, Schirawski J. The tryptophan aminotransferase Tam1 catalyses the single biosynthetic step for tryptophan-dependent pigment synthesis in Ustilago maydis. Mol Microbiol 2008; 68:152-72. [DOI: 10.1111/j.1365-2958.2008.06144.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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