1
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Young AP, Bandarian V. Insertion of 4-Demethylwyosine in tRNA Phe Catalyzed by the Radical S-Adenosyl-l-methionine Enzyme TYW1 Entails Oxidative Cleavage of Pyruvate to Form CO 2. Biochemistry 2022; 61:2643-2647. [PMID: 36326713 PMCID: PMC10874244 DOI: 10.1021/acs.biochem.2c00519] [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] [Indexed: 11/06/2022]
Abstract
The radical S-adenosyl-l-methionine (SAM) enzyme TYW1 catalyzes the condensation of C-2 and C-3 atoms of pyruvate with N-methylguanosine containing tRNAPhe to form 4-demethylwyosine (imG-14) modified tRNAPhe. The fate of C-1 is not known, and either formate or carbon dioxide (CO2) has been proposed. In this study, a coupled assay that transforms either CO2 or formate to oxaloacetate (OAA) was used to determine the fate of C-1. In the presence of [1-13C1]-pyruvate, 13C-enriched OAA was observed in a process that is concomitant with the formation of imG-14, under conditions that preferentially transform CO2 and not formate to OAA. These findings are discussed in the context of the cofactor content of TYW1 and a new role for the auxiliary cluster in catalyzing the oxidative cleavage of C-1-C-2 bond of pyruvate in the catalytic cycle of TYW1.
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Affiliation(s)
| | - Vahe Bandarian
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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2
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Clark KA, Bushin LB, Seyedsayamdost MR. RaS-RiPPs in Streptococci and the Human Microbiome. ACS BIO & MED CHEM AU 2022; 2:328-339. [PMID: 35996476 PMCID: PMC9389541 DOI: 10.1021/acsbiomedchemau.2c00004] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
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Radical S-adenosylmethionine (RaS) enzymes have
quickly advanced to one of the most abundant and versatile enzyme
superfamilies known. Their chemistry is predicated upon reductive
homolytic cleavage of a carbon–sulfur bond in cofactor S-adenosylmethionine forming an oxidizing carbon-based radical,
which can initiate myriad radical transformations. An emerging role
for RaS enzymes is their involvement in the biosynthesis of ribosomally
synthesized and post-translationally modified peptides (RiPPs), a
natural product family that has become known as RaS-RiPPs. These metabolites
are especially prevalent in human and mammalian microbiomes because
the complex chemistry of RaS enzymes gives rise to correspondingly
complex natural products with minimal cellular energy and genomic
fingerprint, a feature that is advantageous in microbes with small,
host-adapted genomes in competitive environments. Herein, we review
the discovery and characterization of RaS-RiPPs from the human microbiome
with a focus on streptococcal bacteria. We discuss the varied chemical
modifications that RaS enzymes introduce onto their peptide substrates
and the diverse natural products that they give rise to. The majority
of RaS-RiPPs remain to be discovered, providing an intriguing avenue
for future investigations at the intersection of metalloenzymology,
chemical ecology, and the human microbiome.
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Affiliation(s)
- Kenzie A Clark
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Leah B Bushin
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Mohammad R Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.,Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
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3
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Hanževački M, Croft AK, Jäger CM. Activation of Glycyl Radical Enzymes─Multiscale Modeling Insights into Catalysis and Radical Control in a Pyruvate Formate-Lyase-Activating Enzyme. J Chem Inf Model 2022; 62:3401-3414. [PMID: 35771966 PMCID: PMC9326890 DOI: 10.1021/acs.jcim.2c00362] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pyruvate formate-lyase (PFL) is a glycyl radical enzyme (GRE) playing a pivotal role in the metabolism of strict and facultative anaerobes. Its activation is carried out by a PFL-activating enzyme, a member of the radical S-adenosylmethionine (rSAM) superfamily of metalloenzymes, which introduces a glycyl radical into the Gly radical domain of PFL. The activation mechanism is still not fully understood and is structurally based on a complex with a short model peptide of PFL. Here, we present extensive molecular dynamics simulations in combination with quantum mechanics/molecular mechanics (QM/MM)-based kinetic and thermodynamic reaction evaluations of a more complete activation model comprising the 49 amino acid long C-terminus region of PFL. We reveal the benefits and pitfalls of the current activation model, providing evidence that the bound peptide conformation does not resemble the bound protein-protein complex conformation with PFL, with implications for the activation process. Substitution of the central glycine with (S)- and (R)-alanine showed excellent binding of (R)-alanine over unstable binding of (S)-alanine. Radical stabilization calculations indicate that a higher radical stability of the glycyl radical might not be the sole origin of the evolutionary development of GREs. QM/MM-derived radical formation kinetics further demonstrate feasible activation barriers for both peptide and C-terminus activation, demonstrating why the crystalized model peptide system is an excellent inhibitory system for natural activation. This new evidence supports the theory that GREs converged on glycyl radical formation due to the better conformational accessibility of the glycine radical loop, rather than the highest radical stability of the formed peptide radicals.
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Affiliation(s)
- Marko Hanževački
- Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, U.K
| | - Anna K Croft
- Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, U.K
| | - Christof M Jäger
- Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, U.K
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4
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Bandarian V. Journey on the Radical SAM Road as an Accidental Pilgrim. ACS BIO & MED CHEM AU 2022; 2:187-195. [PMID: 35726327 PMCID: PMC9204691 DOI: 10.1021/acsbiomedchemau.1c00059] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/13/2022] [Accepted: 01/19/2022] [Indexed: 11/30/2022]
Abstract
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Radical S-adenosyl-l-methionine (SAM)
enzymes catalyze a diverse group of complex transformations in all
aspects of cellular physiology. These metalloenzymes bind SAM to a
4Fe–4S cluster and reductively cleave SAM to generate a 5′-deoxyadenosyl
radical, which generally initiates the catalytic cycle by catalyzing
a H atom to activate the substrate for subsequent chemistry. This
perspective will focus on our discovery of several members of this
superfamily of enzymes, with a particular emphasis on the current
state of the field, challenges, and outlook.
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Affiliation(s)
- Vahe Bandarian
- Department of Chemistry, University of Utah, 315 S 1400 E, Salt Lake City, Utah 84112, United States
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5
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Zhang J, Hou X, Chen Z, Ko Y, Ruszczycky MW, Chen Y, Zhou J, Liu HW. Dioxane Bridge Formation during the Biosynthesis of Spectinomycin Involves a Twitch Radical S-Adenosyl Methionine Dehydrogenase That May Have Evolved from an Epimerase. J Am Chem Soc 2022; 144:9910-9919. [PMID: 35622017 DOI: 10.1021/jacs.2c02676] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Spectinomycin is a dioxane-bridged, tricyclic aminoglycoside produced by Streptomyces spectabilis ATCC 27741. While the spe biosynthetic gene cluster for spectinomycin has been reported, the chemistry underlying construction of the dioxane ring is unknown. The twitch radical SAM enzyme SpeY from the spe cluster is shown here to catalyze dehydrogenation of the C2' alcohol of (2'R,3'S)-tetrahydrospectinomycin to yield (3'S)-dihydrospectinomycin as a likely biosynthetic intermediate. This reaction is radical-mediated and initiated via H atom abstraction from C2' of the substrate by the 5'-deoxyadenosyl radical equivalent generated upon reductive cleavage of SAM. Crystallographic analysis of the ternary Michaelis complex places serine-183 adjacent to C2' of the bound substrate opposite C5' of SAM. Mutation of this residue to cysteine converts SpeY to the corresponding C2' epimerase mirroring the opposite phenomenon observed in the homologous twitch radical SAM epimerase HygY from the hygromycin B biosynthetic pathway. Phylogenetic analysis suggests a relatively recent evolutionary branching of putative twitch radical SAM epimerases bearing homologous cysteine residues to generate the SpeY clade of enzymes.
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Affiliation(s)
- Jiawei Zhang
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Xueli Hou
- Shaanxi Key Laboratory of Natural Products & Chemical Biology, College of Chemistry & Pharmacy, Northwest A&F University, Yangling 712100, Shaanxi, China.,State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhang Chen
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Yeonjin Ko
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Mark W Ruszczycky
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, Texas 78712, United States
| | - Yutian Chen
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, Texas 78712, United States
| | - Jiahai Zhou
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China.,CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Hung-Wen Liu
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.,Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, Texas 78712, United States
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6
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Tunçkanat T, Gendron A, Sadler Z, Neitz A, Byquist S, Lie TJ, Allen KD. Lysine 2,3-Aminomutase and a Newly Discovered Glutamate 2,3-Aminomutase Produce β-Amino Acids Involved in Salt Tolerance in Methanogenic Archaea. Biochemistry 2022; 61:1077-1090. [PMID: 35544775 DOI: 10.1021/acs.biochem.2c00014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many methanogenic archaea synthesize β-amino acids as osmolytes that allow survival in high salinity environments. Here, we investigated the radical S-adenosylmethionine (SAM) aminomutases involved in the biosynthesis of Nε-acetyl-β-lysine and β-glutamate in Methanococcus maripaludis C7. Lysine 2,3-aminomutase (KAM), encoded by MmarC7_0106, was overexpressed and purified from Escherichia coli, followed by biochemical characterization. In the presence of l-lysine, SAM, and dithionite, this archaeal KAM had a kcat = 14.3 s-1 and a Km = 19.2 mM. The product was shown to be 3(S)-β-lysine, which is like the well-characterized Clostridium KAM as opposed to the E. coli KAM that produces 3(R)-β-lysine. We further describe the function of MmarC7_1783, a putative radical SAM aminomutase with a ∼160 amino acid extension at its N-terminus. Bioinformatic analysis of the possible substrate-binding residues suggested a function as glutamate 2,3-aminomutase, which was confirmed here through heterologous expression in a methanogen followed by detection of β-glutamate in cell extracts. β-Glutamate has been known to serve as an osmolyte in select methanogens for a long time, but its biosynthetic origin remained unknown until now. Thus, this study defines the biosynthetic routes for β-lysine and β-glutamate in M. maripaludis and expands the importance and diversity of radical SAM enzymes in all domains of life.
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Affiliation(s)
- Taylan Tunçkanat
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Aleksei Gendron
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Zoie Sadler
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Alex Neitz
- Department of Chemistry and Biochemistry, Gonzaga University, Spokane, Washington 99258, United States
| | - Sarah Byquist
- Department of Chemistry and Biochemistry, Gonzaga University, Spokane, Washington 99258, United States
| | - Thomas J Lie
- Department of Microbiology, University of Washington, Seattle, Washington 98195, United States
| | - Kylie D Allen
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
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7
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Maity AN, Chen JR, Li QY, Ke SC. The Nitrogen Atom of Vitamin B 6 Is Essential for the Catalysis of Radical Aminomutases. Int J Mol Sci 2022; 23:ijms23095210. [PMID: 35563602 PMCID: PMC9105233 DOI: 10.3390/ijms23095210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/03/2022] [Accepted: 05/04/2022] [Indexed: 11/16/2022] Open
Abstract
Radical aminomutases are pyridoxal 5'-phosphate (PLP, a B6 vitamer)-dependent enzymes that require the generation of a 5'-deoxyadenosyl radical to initiate the catalytic cycle, to perform a 1,2 amino group shift reaction. The role of the nitrogen atom of PLP in radical aminomutases has not been investigated extensively yet. We report an alternative synthetic procedure to provide easy access to 1-deazaPLP (dAPLP), an isosteric analog of PLP which acts as a probe for studying the role of the nitrogen atom. Our results revealed that lysine 5,6-aminomutase (5,6-LAM), a radical aminomutase, reconstituted with dAPLP cannot turn over a substrate, demonstrating that the nitrogen atom is essential for radical aminomutases. In contrast, biochemical and spectroscopic studies on the S238A variant reconstituted with PLP revealed a minuscule loss of activity. This apparent anomaly can be explained by a water-mediated rescue of activity in S238A, as if mimicking the active site of lysine 2,3-aminomutase. This study leads to a better comprehension of how enzymes harness the optimum capability of PLP to realize catalysis.
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8
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Wang B, Wu P, Shaik S. Critical Roles of Exchange and Superexchange Interactions in Dictating Electron Transfer and Reactivity in Metalloenzymes. J Phys Chem Lett 2022; 13:2871-2877. [PMID: 35325545 DOI: 10.1021/acs.jpclett.2c00513] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Electron transfer (ET) is a fundamental process in transition-metal-dependent metalloenzymes. In these enzymes, the spin-spin interactions within the same metal center and/or between different metal sites can play a pivotal role in the catalytic cycle and reactivity. This Perspective highlights that the exchange and/or superexchange interactions can intrinsically modulate the inner-sphere and long-range electron transfer, thus controlling the mechanism and activity of metalloenzymes. For mixed-valence diiron oxygenases, the spin-regulated inner-sphere ET can be dictated by exchange interactions, leading to efficient O-O bond activations. Likewise, the spin-regulated inner-sphere ET can be enhanced by both exchange and superexchange interactions in [Fe4S4]-dependent SAM enzymes, which enable the efficient cleavage of the S─C(γ) or S─C5' bond of SAM. In addition to inner-sphere ET, superexchange interactions may modulate the long-range ET between metalloenzymes. We anticipate that the exchange and superexchange enhanced reactivity could be applicable in other important metalloenzymes, such as Photosystem II and nitrogenases.
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Affiliation(s)
- Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P.R. China
| | - Peng Wu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P.R. China
| | - Sason Shaik
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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9
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Lundahl MN, Sarksian R, Yang H, Jodts RJ, Pagnier A, Smith DF, Mosquera MA, van der Donk WA, Hoffman BM, Broderick WE, Broderick JB. Mechanism of Radical S-Adenosyl-l-methionine Adenosylation: Radical Intermediates and the Catalytic Competence of the 5'-Deoxyadenosyl Radical. J Am Chem Soc 2022; 144:5087-5098. [PMID: 35258967 PMCID: PMC9524473 DOI: 10.1021/jacs.1c13706] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Radical S-adenosyl-l-methionine (SAM) enzymes employ a [4Fe-4S] cluster and SAM to initiate diverse radical reactions via either H-atom abstraction or substrate adenosylation. Here we use freeze-quench techniques together with electron paramagnetic resonance (EPR) spectroscopy to provide snapshots of the reaction pathway in an adenosylation reaction catalyzed by the radical SAM enzyme pyruvate formate-lyase activating enzyme on a peptide substrate containing a dehydroalanine residue in place of the target glycine. The reaction proceeds via the initial formation of the organometallic intermediate Ω, as evidenced by the characteristic EPR signal with g∥ = 2.035 and g⊥ = 2.004 observed when the reaction is freeze-quenched at 500 ms. Thermal annealing of frozen Ω converts it into a second paramagnetic species centered at giso = 2.004; this second species was generated directly using freeze-quench at intermediate times (∼8 s) and unequivocally identified via isotopic labeling and EPR spectroscopy as the tertiary peptide radical resulting from adenosylation of the peptide substrate. An additional paramagnetic species observed in samples quenched at intermediate times was revealed through thermal annealing while frozen and spectral subtraction as the SAM-derived 5'-deoxyadenosyl radical (5'-dAdo•). The time course of the 5'-dAdo• and tertiary peptide radical EPR signals reveals that the former generates the latter. These results thus support a mechanism in which Ω liberates 5'-dAdo• by Fe-C5' bond homolysis, and the 5'-dAdo• attacks the dehydroalanine residue of the peptide substrate to form the adenosylated peptide radical species. The results thus provide a picture of a catalytically competent 5'-dAdo• intermediate trapped just prior to reaction with the substrate.
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Affiliation(s)
- Maike N. Lundahl
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Raymond Sarksian
- Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Hao Yang
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Richard J. Jodts
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Adrien Pagnier
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Donald F. Smith
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Martín A. Mosquera
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Wilfred A. van der Donk
- Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Brian M. Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - William E. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Joan B. Broderick
- Corresponding Author: Joan B. Broderick – Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States;
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10
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Chen JR, Ke TX, Frey PA, Ke SC. Electron Spin Echo Envelope Modulation Spectroscopy Reveals How Adenosylcobalamin-Dependent Lysine 5,6-Aminomutase Positions the Radical Pair Intermediates and Modulates Their Stabilities for Efficient Catalysis. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jun-Ru Chen
- Physics Department, National Dong Hwa University, Hualien 974301, Taiwan
| | - Ting-Xi Ke
- Physics Department, National Dong Hwa University, Hualien 974301, Taiwan
| | - Perry A. Frey
- Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53726, United States
| | - Shyue-Chu Ke
- Physics Department, National Dong Hwa University, Hualien 974301, Taiwan
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11
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Besandre RA, Chen Z, Davis I, Zhang J, Ruszczycky MW, Liu A, Liu HW. HygY Is a Twitch Radical SAM Epimerase with Latent Dehydrogenase Activity Revealed upon Mutation of a Single Cysteine Residue. J Am Chem Soc 2021; 143:15152-15158. [PMID: 34491039 DOI: 10.1021/jacs.1c05727] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
HygY is a SPASM/twitch radical SAM enzyme hypothesized to catalyze the C2'-epimerization of galacamine during the biosynthesis of hygromycin B. This activity is confirmed via biochemical and structural analysis of the derivatized reaction products using chemically synthesized deuterated substrate, high-resolution mass spectrometry and 1H NMR. Electron paramagnetic resonance spectroscopy of the reduced enzyme is consistent with ligation of two [Fe4S4] clusters characteristic of the twitch radical SAM subgroup. HygY catalyzed epimerization proceeds with incorporation of a single solvent Hydron into the talamine product facilitated by the catalytic cysteine-183 residue. Mutation of this cysteine to alanine converts HygY from a C2'-epimerase to an C2'-dehydrogenase with comparable activity. The SPASM/twitch radical SAM enzymes often serve as anaerobic oxidases making the redox-neutral epimerases in this class rather interesting. The discovery of latent dehydrogenase activity in a twitch epimerase may therefore offer new insights into the mechanistic features that distinguish oxidative versus redox-neutral SPASM/twitch enzymes and lead to the evolution of new enzyme activities.
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Affiliation(s)
- Ronald A Besandre
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, United States
| | - Zhang Chen
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, United States
| | - Ian Davis
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - Jiawei Zhang
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, United States
| | - Mark Walter Ruszczycky
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, United States
| | - Aimin Liu
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, United States
| | - Hung-Wen Liu
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, United States.,Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, United States
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12
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Impano S, Yang H, Jodts RJ, Pagnier A, Swimley R, McDaniel EC, Shepard EM, Broderick WE, Broderick JB, Hoffman BM. Active-Site Controlled, Jahn-Teller Enabled Regioselectivity in Reductive S-C Bond Cleavage of S-Adenosylmethionine in Radical SAM Enzymes. J Am Chem Soc 2021; 143:335-348. [PMID: 33372786 PMCID: PMC7934139 DOI: 10.1021/jacs.0c10925] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Catalysis by canonical radical S-adenosyl-l-methionine (SAM) enzymes involves electron transfer (ET) from [4Fe-4S]+ to SAM, generating an R3S0 radical that undergoes regioselective homolytic reductive cleavage of the S-C5' bond to generate the 5'-dAdo· radical. However, cryogenic photoinduced S-C bond cleavage has regioselectively yielded either 5'-dAdo· or ·CH3, and indeed, each of the three SAM S-C bonds can be regioselectively cleaved in an RS enzyme. This diversity highlights a longstanding central question: what controls regioselective homolytic S-C bond cleavage upon SAM reduction? We here provide an unexpected answer, founded on our observation that photoinduced S-C bond cleavage in multiple canonical RS enzymes reveals two enzyme classes: in one, photolysis forms 5'-dAdo·, and in another it forms ·CH3. The identity of the cleaved S-C bond correlates with SAM ribose conformation but not with positioning and orientation of the sulfonium center relative to the [4Fe-4S] cluster. We have recognized the reduced-SAM R3S0 radical is a (2E) state with its antibonding unpaired electron in an orbital doublet, which renders R3S0 Jahn-Teller (JT)-active and therefore subject to vibronically induced distortion. Active-site forces induce a JT distortion that localizes the odd electron in a single priority S-C antibond, which undergoes regioselective cleavage. In photolytic cleavage those forces act through control of the ribose conformation and are transmitted to the sulfur via the S-C5' bond, but during catalysis thermally induced conformational changes that enable ET from a cluster iron generate dominant additional forces that specifically select S-C5' for cleavage. This motion also can explain how 5'-dAdo· subsequently forms the organometallic intermediate Ω.
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Affiliation(s)
- Stella Impano
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Hao Yang
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Richard J Jodts
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Adrien Pagnier
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Ryan Swimley
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Elizabeth C McDaniel
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Eric M Shepard
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - William E Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Joan B Broderick
- Department of Chemistry & Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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13
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Ghosh S, Marsh ENG. Viperin: An ancient radical SAM enzyme finds its place in modern cellular metabolism and innate immunity. J Biol Chem 2020; 295:11513-11528. [PMID: 32546482 PMCID: PMC7450102 DOI: 10.1074/jbc.rev120.012784] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/16/2020] [Indexed: 12/13/2022] Open
Abstract
Viperin plays an important and multifaceted role in the innate immune response to viral infection. Viperin is also notable as one of very few radical SAM-dependent enzymes present in higher animals; however, the enzyme appears broadly conserved across all kingdoms of life, which suggests that it represents an ancient defense mechanism against viral infections. Although viperin was discovered some 20 years ago, only recently was the enzyme's structure determined and its catalytic activity elucidated. The enzyme converts CTP to 3'-deoxy-3',4'-didehydro-CTP, which functions as novel chain-terminating antiviral nucleotide when misincorporated by viral RNA-dependent RNA polymerases. Moreover, in higher animals, viperin interacts with numerous other host and viral proteins, and it is apparent that this complex network of interactions constitutes another important aspect of the protein's antiviral activity. An emerging theme is that viperin appears to facilitate ubiquitin-dependent proteasomal degradation of some of the proteins it interacts with. Viperin-targeted protein degradation contributes to the antiviral response either by down-regulating various metabolic pathways important for viral replication or by directly targeting viral proteins for degradation. Here, we review recent advances in our understanding of the structure and catalytic activity of viperin, together with studies investigating the interactions between viperin and its target proteins. These studies have provided detailed insights into the biochemical processes underpinning this unusual enzyme's wide-ranging antiviral activity. We also highlight recent intriguing reports that implicate a broader role for viperin in regulating nonpathological cellular processes, including thermogenesis and protein secretion.
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Affiliation(s)
- Soumi Ghosh
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - E Neil G Marsh
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan, USA
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14
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Chen X, Zard SZ. Convergent Route to β-Amino Acids and to β-Heteroarylethylamines: An Unexpected Vinylation Reaction. Org Lett 2020; 22:3628-3632. [PMID: 32314926 DOI: 10.1021/acs.orglett.0c01087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Various protected β2-amino acids can be prepared by radical addition of β-phthalimido-α-xanthyl propionic acid, both as the free acid or as the ethyl ester. Successive radical additions provide access to more complex structures. In the case of the free acid, addition to certain heteroaromatics leads directly to β-heteroarylethylamines through spontaneous decarboxylation of the intermediate adduct. Forcing the decarboxylation in some cases generated a vinyl group by decarboxylative elimination of the phthalimido group.
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Affiliation(s)
- Xuan Chen
- Laboratoire de Synthèse Organique, CNRS UMR 7652 Ecole Polytechnique, 91128 Cedex Palaiseau, France
| | - Samir Z Zard
- Laboratoire de Synthèse Organique, CNRS UMR 7652 Ecole Polytechnique, 91128 Cedex Palaiseau, France
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15
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16
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Yang H, McDaniel EC, Impano S, Byer AS, Jodts RJ, Yokoyama K, Broderick WE, Broderick JB, Hoffman BM. The Elusive 5'-Deoxyadenosyl Radical: Captured and Characterized by Electron Paramagnetic Resonance and Electron Nuclear Double Resonance Spectroscopies. J Am Chem Soc 2019; 141:12139-12146. [PMID: 31274303 DOI: 10.1021/jacs.9b05926] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The 5'-deoxyadenosyl radical (5'-dAdo·) abstracts a substrate H atom as the first step in radical-based transformations catalyzed by adenosylcobalamin-dependent and radical S-adenosyl-l-methionine (RS) enzymes. Notwithstanding its central biological role, 5'-dAdo· has eluded characterization despite efforts spanning more than a half-century. Here, we report generation of 5'-dAdo· in a RS enzyme active site at 12 K using a novel approach involving cryogenic photoinduced electron transfer from the [4Fe-4S]+ cluster to the coordinated S-adenosylmethionine (SAM) to induce homolytic S-C5' bond cleavage. We unequivocally reveal the structure of this long-sought radical species through the use of electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) spectroscopies with isotopic labeling, complemented by density-functional computations: a planar C5' (2pπ) radical (∼70% spin occupancy); the C5'(H)2 plane is rotated by ∼37° (experiment)/39° (DFT) relative to the C5'-C4'-(C4'-H) plane, placing a C5'-H antiperiplanar to the ribose-ring oxygen, which helps stabilize the radical against elimination of the 4'-H. The agreement between φ from experiment and in vacuo DFT indicates that the conformation is intrinsic to 5-dAdo· itself, and not determined by its environment.
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Affiliation(s)
- Hao Yang
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Elizabeth C McDaniel
- Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Stella Impano
- Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Amanda S Byer
- Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Richard J Jodts
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Kenichi Yokoyama
- Department of Biochemistry , Duke University , Durham , North Carolina 27710 , United States
| | - William E Broderick
- Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Joan B Broderick
- Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Brian M Hoffman
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
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17
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Ruszczycky MW, Zhong A, Liu HW. Following the electrons: peculiarities in the catalytic cycles of radical SAM enzymes. Nat Prod Rep 2019; 35:615-621. [PMID: 29485151 DOI: 10.1039/c7np00058h] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Radical SAM enzymes use S-adenosyl-l-methionine as an oxidant to initiate radical-mediated transformations that would otherwise not be possible with Lewis acid/base chemistry alone. These reactions are either redox neutral or oxidative leading to certain expectations regarding the role of SAM as either a reusable cofactor or the ultimate electron acceptor during each turnover. However, these expectations are frequently not realized resulting in fundamental questions regarding the redox handling and movement of electrons associated with these biological catalysts. Herein we provide a focused perspective on several of these questions and associated hypotheses with an emphasis on recently discovered radical SAM enzymes.
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Affiliation(s)
- Mark W Ruszczycky
- Division of Chemical Biology & Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, USA.
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18
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Cinar ME, Lal M, Deiseroth HJ, Schlirf J, Schmittel M. Detection and follow-up reactions of distonic β
, β
-dimesityl enol radical cations containing nitrogen heterocyclic bases. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3865] [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)
- M. Emin Cinar
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
| | - Mukul Lal
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
| | | | - Jens Schlirf
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
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19
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White RH. Identification and Biosynthesis of 1-Mercaptoethanesulfonic Acid (1-MES), an Analogue of Coenzyme M, Found Widely in the Methanogenic Archaea. Biochemistry 2017; 56:6137-6144. [PMID: 29064676 DOI: 10.1021/acs.biochem.7b00971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Here I report on the identification of 1-mercaptoethanesulfonic acid (1-MES), an analogue of 2-mercaptoethanesulfonic acid (coenzyme M, HSCoM). 1-MES and HSCoM were both present in the growth media of eight different methanogens at concentrations ranging from ∼1 to 100 μM. In an effort to determine a chemical origin of 1-MES, several plausible chemical routes were examined each assuming that HSCoM was the precursor. In all examined routes, no 1-MES was formed. However, 1-MES was formed when a solution of vinylsulfonic acid and sulfide were exposed to ultraviolet light. On the basis of these results, I conclude 1-MES is formed enzymatically. This was confirmed by growing a culture of Methanococcus maripaludis S2 in the presence of [1,1',2,2'-2H4]HSCoM and measuring the incorporation of deuterium into 1-MES. 1-MES incorporated three of the four deuteriums from the fed HSCoM. This result is consistent with the abstraction of a C-2 deuterium of the HSCoM, likely by a 5'-dAdoCH2• radical, followed by a radical rearrangement in which the sulfonic acid moves to position C-1, followed by abstraction of a H• likely from 5'-dAdoCH2D. At present, the reason for the production of 1-MES is not clear. This is the first report of the occurrence of 1-MES in Nature.
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Affiliation(s)
- Robert H White
- Department of Biochemistry, Virginia Polytechnic Institute and State University , Blacksburg, Virginia 24061, United States
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20
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Ruszczycky MW, Liu HW. Theory and Application of the Relationship Between Steady-State Isotope Effects on Enzyme Intermediate Concentrations and Net Rate Constants. Methods Enzymol 2017; 596:459-499. [PMID: 28911781 PMCID: PMC5837895 DOI: 10.1016/bs.mie.2017.07.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Steady-state kinetic isotope effects on enzyme-catalyzed reactions are often interpreted in terms of the microscopic rate constants associated with the elementary reactions of interest. Unfortunately, this approach can lead to confusion, especially when more than one elementary reaction is isotopically sensitive, because it forces one to consider the full catalytic cycle one step at a time rather than as a complete whole. Herein we argue that shifting focus from intrinsic effects to net rate constants and enzyme intermediate concentrations provides a more natural and holistic interpretation by which the effects of partial rate limitation are more easily understood. In doing so, we demonstrate how the experimental determination of isotope effects on enzyme intermediate concentrations allows a direct determination of isotope effects on net rate constants. The chapter is divided into three main sections. The first outlines the basic theory and its interpretation. The second discusses an application of the theory in the study of the radical SAM enzyme DesII. The final section then provides the complete mathematical treatment.
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Affiliation(s)
| | - Hung-Wen Liu
- University of Texas at Austin, Austin, TX, United States
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21
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Heidinger L, Kneuttinger AC, Kashiwazaki G, Weber S, Carell T, Schleicher E. Direct observation of a deoxyadenosyl radical in an active enzyme environment. FEBS Lett 2016; 590:4489-4494. [PMID: 27878994 DOI: 10.1002/1873-3468.12498] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/16/2016] [Accepted: 11/17/2016] [Indexed: 11/11/2022]
Abstract
5'-deoxyadenosyl radicals have been proposed as the first common intermediate in the molecular reaction mechanism of the family of radical S-adenosyl-l-methionine (SAM) enzymes. However, this radical species has not yet been directly observed in a catalytically active enzyme environment. In a reduced and SAM-containing C140A mutant of the spore photoproduct lyase from Geobacillus thermodenitrificans, a mutant with altered catalytic activity, we were able to identify an organic radical with pronounced hyperfine structure using electron paramagnetic resonance spectroscopy. Guided by quantum-chemical computations at the density functional theory level of theory, this radical could be tentatively assigned to a deoxyadenosyl radical, which provides first experimental evidence for this intermediate in the reaction mechanism of radical SAM enzymes.
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Affiliation(s)
- Lorenz Heidinger
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Germany
| | - Andrea C Kneuttinger
- Department für Chemie, Ludwig-Maximilians-Universität München, Germany.,Institute of Biophysics and Physical Biochemistry, University of Regensburg, Germany
| | - Gengo Kashiwazaki
- Department für Chemie, Ludwig-Maximilians-Universität München, Germany
| | - Stefan Weber
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Germany
| | - Thomas Carell
- Department für Chemie, Ludwig-Maximilians-Universität München, Germany
| | - Erik Schleicher
- Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Germany
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22
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Carbon extension in peptidylnucleoside biosynthesis by radical SAM enzymes. Nat Chem Biol 2016; 12:905-907. [PMID: 27642865 PMCID: PMC5069167 DOI: 10.1038/nchembio.2187] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 08/16/2016] [Indexed: 01/04/2023]
Abstract
Nikkomycins and polyoxins are antifungal peptidylnucleoside antibiotics active against human and plant pathogens. Here we report that during peptidylnucleoside biosynthesis in Streptomyces cacaoi and S. tendae, the C5' extension of the nucleoside essential for downstream structural diversification is catalyzed by a conserved radical S-adenosyl-L-methionine (SAM) enzyme, PolH or NikJ. This is distinct from the nucleophilic mechanism reported for antibacterial nucleosides and represents a new mechanism of nucleoside natural product biosynthesis.
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23
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Park K, Mera PE, Escalante-Semerena JC, Brunold TC. Resonance Raman spectroscopic study of the interaction between Co(II)rrinoids and the ATP:corrinoid adenosyltransferase PduO from Lactobacillus reuteri. J Biol Inorg Chem 2016; 21:669-81. [PMID: 27383231 PMCID: PMC5118822 DOI: 10.1007/s00775-016-1371-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/14/2016] [Indexed: 12/01/2022]
Abstract
The human-type ATP:corrinoid adenosyltransferase PduO from Lactobacillus reuteri (LrPduO) catalyzes the adenosylation of Co(II)rrinoids to generate adenosylcobalamin (AdoCbl) or adenosylcobinamide (AdoCbi(+)). This process requires the formation of "supernucleophilic" Co(I)rrinoid intermediates in the enzyme active site which are properly positioned to abstract the adeonsyl moiety from co-substrate ATP. Previous magnetic circular dichroism (MCD) spectroscopic and X-ray crystallographic analyses revealed that LrPduO achieves the thermodynamically challenging reduction of Co(II)rrinoids by displacing the axial ligand with a non-coordinating phenylalanine residue to produce a four-coordinate species. However, relatively little is currently known about the interaction between the tetradentate equatorial ligand of Co(II)rrinoids (the corrin ring) and the enzyme active site. To address this issue, we have collected resonance Raman (rR) data of Co(II)rrinoids free in solution and bound to the LrPduO active site. The relevant resonance-enhanced vibrational features of the free Co(II)rrinoids are assigned on the basis of rR intensity calculations using density functional theory to establish a suitable framework for interpreting rR spectral changes that occur upon Co(II)rrinoid binding to the LrPduO/ATP complex in terms of structural perturbations of the corrin ring. To complement our rR data, we have also obtained MCD spectra of Co(II)rrinoids bound to LrPduO complexed with the ATP analogue UTP. Collectively, our results provide compelling evidence that in the LrPduO active site, the corrin ring of Co(II)rrinoids is firmly locked in place by several amino acid side chains so as to facilitate the dissociation of the axial ligand.
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Affiliation(s)
- Kiyoung Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Yuseong-gu, Daejeon, 34141, Republic of Korea.
| | - Paola E Mera
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM, 88003, USA
| | | | - Thomas C Brunold
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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24
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Rohac R, Amara P, Benjdia A, Martin L, Ruffié P, Favier A, Berteau O, Mouesca JM, Fontecilla-Camps JC, Nicolet Y. Carbon–sulfur bond-forming reaction catalysed by the radical SAM enzyme HydE. Nat Chem 2016; 8:491-500. [DOI: 10.1038/nchem.2490] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 02/25/2016] [Indexed: 11/09/2022]
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25
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Kim HJ, LeVieux J, Yeh YC, Liu HW. C3'-Deoxygenation of Paromamine Catalyzed by a Radical S-Adenosylmethionine Enzyme: Characterization of the Enzyme AprD4 and Its Reductase Partner AprD3. Angew Chem Int Ed Engl 2016; 55:3724-8. [PMID: 26879038 PMCID: PMC4943880 DOI: 10.1002/anie.201510635] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Indexed: 11/06/2022]
Abstract
C3'-deoxygenation of aminoglycosides results in their decreased susceptibility to phosphorylation thereby increasing their efficacy as antibiotics. However, the biosynthetic mechanism of C3'-deoxygenation is unknown. To address this issue, aprD4 and aprD3 genes from the apramycin gene cluster in Streptomyces tenebrarius were expressed in E. coli and the resulting gene products were characterized in vitro. AprD4 is shown to be a radical S-adenosylmethionine (SAM) enzyme, catalyzing homolysis of SAM to 5'-deoxyadenosine (5'-dAdo) in the presence of paromamine. [4'-(2) H]-Paromamine was prepared and used to show that its C4'-H is transferred to 5'-dAdo by AprD4, during which the substrate is dehydrated to a product consistent with 4'-oxolividamine. In contrast, paromamine is reduced to a deoxy product when incubated with AprD4/AprD3/NADPH. These results show that AprD4 is the first radical SAM diol-dehydratase and, along with AprD3, is responsible for 3'-deoxygenation in aminoglycoside biosynthesis.
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Affiliation(s)
- Hak Joong Kim
- Division of Medicinal Chemistry, College of Pharmacy and Department of Chemistry, University of Texas at Austin, Austin, TX, 78712, USA
| | - Jake LeVieux
- Division of Medicinal Chemistry, College of Pharmacy and Department of Chemistry, University of Texas at Austin, Austin, TX, 78712, USA
| | - Yu-Cheng Yeh
- Division of Medicinal Chemistry, College of Pharmacy and Department of Chemistry, University of Texas at Austin, Austin, TX, 78712, USA
| | - Hung-Wen Liu
- Division of Medicinal Chemistry, College of Pharmacy and Department of Chemistry, University of Texas at Austin, Austin, TX, 78712, USA.
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26
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C3′-Deoxygenation of Paromamine Catalyzed by a RadicalS-Adenosylmethionine Enzyme: Characterization of the Enzyme AprD4 and Its Reductase Partner AprD3. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510635] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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27
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Kitanishi K, Cracan V, Banerjee R. Engineered and Native Coenzyme B12-dependent Isovaleryl-CoA/Pivalyl-CoA Mutase. J Biol Chem 2015; 290:20466-76. [PMID: 26134562 DOI: 10.1074/jbc.m115.646299] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Indexed: 11/06/2022] Open
Abstract
Adenosylcobalamin-dependent isomerases catalyze carbon skeleton rearrangements using radical chemistry. We have recently demonstrated that an isobutyryl-CoA mutase variant, IcmF, a member of this enzyme family that catalyzes the interconversion of isobutyryl-CoA and n-butyryl-CoA also catalyzes the interconversion between isovaleryl-CoA and pivalyl-CoA, albeit with low efficiency and high susceptibility to inactivation. Given the biotechnological potential of the isovaleryl-CoA/pivalyl-CoA mutase (PCM) reaction, we initially attempted to engineer IcmF to be a more proficient PCM by targeting two active site residues predicted based on sequence alignments and crystal structures, to be key to substrate selectivity. Of the eight mutants tested, the F598A mutation was the most robust, resulting in an ∼17-fold increase in the catalytic efficiency of the PCM activity and a concomitant ∼240-fold decrease in the isobutyryl-CoA mutase activity compared with wild-type IcmF. Hence, mutation of a single residue in IcmF tuned substrate specificity yielding an ∼4000-fold increase in the specificity for an unnatural substrate. However, the F598A mutant was even more susceptible to inactivation than wild-type IcmF. To circumvent this limitation, we used bioinformatics analysis to identify an authentic PCM in genomic databases. Cloning and expression of the putative AdoCbl-dependent PCM with an α2β2 heterotetrameric organization similar to that of isobutyryl-CoA mutase and a recently characterized archaeal methylmalonyl-CoA mutase, allowed demonstration of its robust PCM activity. To simplify kinetic analysis and handling, a variant PCM-F was generated in which the αβ subunits were fused into a single polypeptide via a short 11-amino acid linker. The fusion protein, PCM-F, retained high PCM activity and like PCM, was resistant to inactivation. Neither PCM nor PCM-F displayed detectable isobutyryl-CoA mutase activity, demonstrating that PCM represents a novel 5'-deoxyadenosylcobalamin-dependent acyl-CoA mutase. The newly discovered PCM and the derivative PCM-F, have potential applications in bioremediation of pivalic acid found in sludge, in stereospecific synthesis of C5 carboxylic acids and alcohols, and in the production of potential commodity and specialty chemicals.
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Affiliation(s)
- Kenichi Kitanishi
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
| | - Valentin Cracan
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
| | - Ruma Banerjee
- From the Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0600
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28
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Horitani M, Byer AS, Shisler KA, Chandra T, Broderick JB, Hoffman BM. Why Nature Uses Radical SAM Enzymes so Widely: Electron Nuclear Double Resonance Studies of Lysine 2,3-Aminomutase Show the 5'-dAdo• "Free Radical" Is Never Free. J Am Chem Soc 2015; 137:7111-21. [PMID: 25923449 PMCID: PMC4612528 DOI: 10.1021/jacs.5b00498] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lysine 2,3-aminomutase (LAM) is a radical S-adenosyl-L-methionine (SAM) enzyme and, like other members of this superfamily, LAM utilizes radical-generating machinery comprising SAM anchored to the unique Fe of a [4Fe-4S] cluster via a classical five-membered N,O chelate ring. Catalysis is initiated by reductive cleavage of the SAM S-C5' bond, which creates the highly reactive 5'-deoxyadenosyl radical (5'-dAdo•), the same radical generated by homolytic Co-C bond cleavage in B12 radical enzymes. The SAM surrogate S-3',4'-anhydroadenosyl-L-methionine (anSAM) can replace SAM as a cofactor in the isomerization of L-α-lysine to L-β-lysine by LAM, via the stable allylic anhydroadenosyl radical (anAdo•). Here electron nuclear double resonance (ENDOR) spectroscopy of the anAdo• radical in the presence of (13)C, (2)H, and (15)N-labeled lysine completes the picture of how the active site of LAM from Clostridium subterminale SB4 "tames" the 5'-dAdo• radical, preventing it from carrying out harmful side reactions: this "free radical" in LAM is never free. The low steric demands of the radical-generating [4Fe-4S]/SAM construct allow the substrate target to bind adjacent to the S-C5' bond, thereby enabling the 5'-dAdo• radical created by cleavage of this bond to react with its partners by undergoing small motions, ∼0.6 Å toward the target and ∼1.5 Å overall, that are controlled by tight van der Waals contact with its partners. We suggest that the accessibility to substrate and ready control of the reactive C5' radical, with "van der Waals control" of small motions throughout the catalytic cycle, is common within the radical SAM enzyme superfamily and is a major reason why these enzymes are the preferred means of initiating radical reactions in nature.
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Affiliation(s)
- Masaki Horitani
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Amanda S. Byer
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Krista A. Shisler
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Tilak Chandra
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Joan B. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States
| | - Brian M. Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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29
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Affiliation(s)
- Perry Allen Frey
- From the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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30
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Abstract
DesII is a member of the radical SAM family of enzymes that catalyzes radical-mediated transformations of TDP-4-amino-4,6-didexoy-D-glucose as well as other sugar nucleotide diphosphates. Like nearly all radical SAM enzymes, the reactions begin with the reductive homolysis of SAM to produce a 5'-deoxyadenosyl radical which is followed by regiospecific hydrogen atom abstraction from the substrate. What happens next, however, depends on the nature of the substrate radical so produced. In the case of the biosynthetically relevant substrate, a radical-mediated deamination ensues; however, when this amino group is replaced with a hydroxyl, one instead observes dehydrogenation. The factors that govern the fate of the initially generated substrate radical as well as the mechanistic details underlying these transformations have been a key focus of research into the chemistry of DesII. This review will discuss recent discoveries pertaining to the enzymology of DesII, how it may relate to understanding other radical-mediated lyases and dehydrogenases and the working hypotheses currently being investigated regarding the mechanism of DesII catalysis.
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Affiliation(s)
- Mark W. Ruszczycky
- Division of Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, Texas 78712, United States
| | - Hung-wen Liu
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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31
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Salamone M, Basili F, Bietti M. Reactivity and selectivity patterns in hydrogen atom transfer from amino acid C-H bonds to the cumyloxyl radical: polar effects as a rationale for the preferential reaction at proline residues. J Org Chem 2015; 80:3643-50. [PMID: 25774567 DOI: 10.1021/acs.joc.5b00549] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Absolute rate constants for hydrogen atom transfer (HAT) from the C-H bonds of N-Boc-protected amino acids to the cumyloxyl radical (CumO(•)) were measured by laser flash photolysis. With glycine, alanine, valine, norvaline, and tert-leucine, HAT occurs from the α-C-H bonds, and the stability of the α-carbon radical product plays a negligible role. With leucine, HAT from the α- and γ-C-H bonds was observed. The higher kH value measured for proline was explained in terms of polar effects, with HAT that predominantly occurs from the δ-C-H bonds, providing a rationale for the previous observation that proline residues represent favored HAT sites in the reactions of peptides and proteins with (•)OH. Preferential HAT from proline was also observed in the reactions of CumO(•) with the dipeptides N-BocProGlyOH and N-BocGlyGlyOH. The rate constants measured for CumO(•) were compared with the relative rates obtained previously for the corresponding reactions of different hydrogen-abstracting species. The behavior of CumO(•) falls between those observed for the highly reactive radicals Cl(•) and (•)OH and the significantly more stable Br(•). Taken together, these results provide a general framework for the description of the factors that govern reactivity and selectivity patterns in HAT reactions from amino acid C-H bonds.
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Affiliation(s)
- Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Federica Basili
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
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Cutsail GE, Telser J, Hoffman BM. Advanced paramagnetic resonance spectroscopies of iron-sulfur proteins: Electron nuclear double resonance (ENDOR) and electron spin echo envelope modulation (ESEEM). BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1370-94. [PMID: 25686535 DOI: 10.1016/j.bbamcr.2015.01.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/29/2015] [Accepted: 01/29/2015] [Indexed: 12/20/2022]
Abstract
The advanced electron paramagnetic resonance (EPR) techniques, electron nuclear double resonance (ENDOR) and electron spin echo envelope modulation (ESEEM) spectroscopies, provide unique insights into the structure, coordination chemistry, and biochemical mechanism of nature's widely distributed iron-sulfur cluster (FeS) proteins. This review describes the ENDOR and ESEEM techniques and then provides a series of case studies on their application to a wide variety of FeS proteins including ferredoxins, nitrogenase, and radical SAM enzymes. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- George E Cutsail
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, IL 60605, USA
| | - Brian M Hoffman
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA.
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Han S, Jones RA, Quiclet-Sire B, Zard SZ. A convergent route to functional protected amines, diamines, and β-amino acids. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.07.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Doitomi K, Tanaka H, Kamachi T, Toraya T, Yoshizawa K. Computational Mutation Design of Diol Dehydratase: Catalytic Ability toward Glycerol beyond the Wild-Type Enzyme. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2014. [DOI: 10.1246/bcsj.20140115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kazuki Doitomi
- Institute for Materials Chemistry and Engineering, Kyushu University
- International Research Center for Molecular Systems, Kyushu University
| | - Hiromasa Tanaka
- Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University
| | - Takashi Kamachi
- Institute for Materials Chemistry and Engineering, Kyushu University
- International Research Center for Molecular Systems, Kyushu University
| | - Tetsuo Toraya
- Department of Bioscience and Biotechnology, Okayama University
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering, Kyushu University
- International Research Center for Molecular Systems, Kyushu University
- Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University
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Pang J, Scrutton NS, Sutcliffe MJ. Quantum Mechanics/Molecular Mechanics Studies on the Mechanism of Action of Cofactor Pyridoxal 5′-Phosphate in Ornithine 4,5-Aminomutase. Chemistry 2014; 20:11390-401. [DOI: 10.1002/chem.201402759] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Indexed: 02/02/2023]
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