1
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Katoch A, Mandal D. Impact of carboxylate ligation on the C-H activation reactivity of a non-heme Fe(IV)O complex: a computational investigation. Dalton Trans 2024; 53:15264-15272. [PMID: 39222036 DOI: 10.1039/d4dt02139h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
A comprehensive DFT investigation has been presented to predict how a carboxylate-rich macrocycle would affect the reactivity of a non-heme Fe(IV)O complex towards C-H activation. The popular non-heme iron oxo complex [FeIV(O)(N4Py)]2+, (N4Py = N,N-(bis(2-pyridyl)methyl)N-bis(2-pyridylmethyl)amine) (1), has been selected here as the primary compound. It is transformed to the compound [FeIV(O)(nBu-P2DA)], where nBu-P2DA = N-(1',1'-bis(2-pyridyl)pentyl)iminodiacetate (2) after the replacement of two pyridine donors of N4Py with carboxylate groups. Two other complexes, namely 3 and 4, have been predicted sequentially substituting nitrogen with the carboxylate groups. Ethylbenzene and dihydrotoluene were chosen as substrates. In terms of C-H activation reactivity, an interesting pattern emerges: as the carboxylate group becomes more equatorially enriched, the reactivity increases, following the trend 1 < 2 < 3 < 4. This also aligns with available experimental reports related to complexes 1 and 2. Fe(IV)O complexes exhibit two-state reactivity (triplet and quintet), whereas the quintet state is more favourable due to the stabilization of the transition states through exchange interactions involving a greater number of unpaired electrons. A detailed analysis of the factors influencing reactivity has been performed, including distortion energy (which decreases for the transition state with the addition of carboxylate groups), the triplet-quintet oxidant energy gap (which consistently decreases as carboxylate group enrichment increases), steric factors, and quantum mechanical tunneling. This investigation provides a detailed explanation of the observed outcomes and predicts the higher reactivity of carboxylate-enriched Fe(IV)O complexes. After potential experimental verification, this could lead to the development of new, optimal catalysts for C-H activation.
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Affiliation(s)
- Akanksha Katoch
- Department of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala-147001, Punjab, India.
| | - Debasish Mandal
- Department of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala-147001, Punjab, India.
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2
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Gera R, De P, Singh KK, Jannuzzi SAV, Mohanty A, Velasco L, Kulbir, Kumar P, Marco JF, Nagarajan K, Pecharromán C, Rodríguez-Pascual PM, DeBeer S, Moonshiram D, Gupta SS, Dasgupta J. Trapping an Elusive Fe(IV)-Superoxo Intermediate Inside a Self-Assembled Nanocage in Water at Room Temperature. J Am Chem Soc 2024; 146:21729-21741. [PMID: 39078020 DOI: 10.1021/jacs.4c05849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Molecular cavities that mimic natural metalloenzymes have shown the potential to trap elusive reaction intermediates. Here, we demonstrate the formation of a rare yet stable Fe(IV)-superoxo intermediate at room temperature subsequent to dioxygen binding at the Fe(III) site of a (Et4N)2[FeIII(Cl)(bTAML)] complex confined inside the hydrophobic interior of a water-soluble Pd6L412+ nanocage. Using a combination of electron paramagnetic resonance, Mössbauer, Raman/IR vibrational, X-ray absorption, and emission spectroscopies, we demonstrate that the cage-encapsulated complex has a Fe(IV) oxidation state characterized by a stable S = 1/2 spin state and a short Fe-O bond distance of ∼1.70 Å. We find that the O2 reaction in confinement is reversible, while the formed Fe(IV)-superoxo complex readily reacts when presented with substrates having weak C-H bonds, highlighting the lability of the O-O bond. We envision that such optimally trapped high-valent superoxos can show new classes of reactivities catalyzing both oxygen atom transfer and C-H bond activation reactions.
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Affiliation(s)
- Rahul Gera
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
- Department of Education in Science and Mathematics, Regional Institute of Education - Mysuru, NCERT, Mysuru 570006, India
| | - Puja De
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Kundan K Singh
- Chemical Engineering Division, CSIR-National Chemical Laboratory, Pune, Maharashtra 411008, India
- Chemistry Department, Indian Institute of Technology, Dharwad 580007, India
| | - Sergio A V Jannuzzi
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, Mülheim an der Ruhr 45470, Germany
| | - Aisworika Mohanty
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Lucia Velasco
- Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Kulbir
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India
| | - Pankaj Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India
| | - J F Marco
- Instituto de Quimica Fisica Blas Cabrera, Consejo Superior de Investigaciones Científicas, Serrano 119, Madrid 28006, Spain
| | - Kalaivanan Nagarajan
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Carlos Pecharromán
- Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - P M Rodríguez-Pascual
- Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Serena DeBeer
- Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, Mülheim an der Ruhr 45470, Germany
| | - Dooshaye Moonshiram
- Instituto de Ciencia de Materiales de Madrid Consejo Superior de Investigaciones Científicas Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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3
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Hardy FJ, Quesne MG, Gérard EF, Zhao J, Ortmayer M, Taylor CJ, Ali HS, Slater JW, Levy CW, Heyes DJ, Bollinger JM, de Visser SP, Green AP. Probing Ferryl Reactivity in a Nonheme Iron Oxygenase Using an Expanded Genetic Code. ACS Catal 2024; 14:11584-11590. [PMID: 39114090 PMCID: PMC11301626 DOI: 10.1021/acscatal.4c02365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/03/2024] [Accepted: 07/08/2024] [Indexed: 08/10/2024]
Abstract
The ability to introduce noncanonical amino acids as axial ligands in heme enzymes has provided a powerful experimental tool for studying the structure and reactivity of their FeIV=O ("ferryl") intermediates. Here, we show that a similar approach can be used to perturb the conserved Fe coordination environment of 2-oxoglutarate (2OG) dependent oxygenases, a versatile class of enzymes that employ highly-reactive ferryl intermediates to mediate challenging C-H functionalizations. Replacement of one of the cis-disposed histidine ligands in the oxygenase VioC with a less electron donating N δ-methyl-histidine (MeHis) preserves both catalytic function and reaction selectivity. Significantly, the key ferryl intermediate responsible for C-H activation can be accumulated in both the wildtype and the modified protein. In contrast to heme enzymes, where metal-oxo reactivity is extremely sensitive to the nature of the proximal ligand, the rates of C-H activation and the observed large kinetic isotope effects are only minimally affected by axial ligand replacement in VioC. This study showcases a powerful tool for modulating the coordination sphere of nonheme iron enzymes that will enhance our understanding of the factors governing their divergent activities.
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Affiliation(s)
- Florence J. Hardy
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Matthew G. Quesne
- Research
Complex at Harwell, Rutherford Appleton
Laboratory, Harwell Oxford, Didcot, Oxon OX11
0FA, U.K.
- School
of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
| | - Emilie F. Gérard
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Jingming Zhao
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Mary Ortmayer
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Christopher J. Taylor
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Hafiz S. Ali
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Jeffrey W. Slater
- Department
of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Colin W. Levy
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Derren J. Heyes
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - J. Martin Bollinger
- Department
of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Sam P. de Visser
- Department
of Chemical Engineering & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
| | - Anthony P. Green
- Department
of Chemistry & Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K.
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4
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Nguy AKL, Martinie RJ, Cai A, Seyedsayamdost MR. Detection of a Kinetically Competent Compound-I Intermediate in the Vancomycin Biosynthetic Enzyme OxyB. J Am Chem Soc 2024; 146:19629-19634. [PMID: 38989876 DOI: 10.1021/jacs.4c03102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
Cytochrome P450 enzymes are abundantly encoded in microbial genomes. Their reactions have two general outcomes, one involving oxygen insertion via a canonical "oxygen rebound" mechanism and a second that diverts from this pathway and leads to a wide array of products, notably intramolecular oxidative cross-links. The antibiotic of-last-resort, vancomycin, contains three such cross-links, which are crucial for biological activity and are installed by the P450 enzymes OxyB, OxyA, and OxyC. The mechanisms of these enzymes have remained elusive in part because of the difficulty in spectroscopically capturing transient intermediates. Using stopped-flow UV/visible absorption and rapid freeze-quench electron paramagnetic resonance spectroscopies, we show that OxyB generates the highly reactive compound-I intermediate, which can react with a model vancomycin peptide substrate in a kinetically competent fashion to generate product. Our results have implications for the mechanism of OxyB and are in line with the notion that oxygen rebound and oxidative cross-links share early steps in their catalytic cycles.
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Affiliation(s)
- Andy K L Nguy
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Ryan J Martinie
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Amanda Cai
- 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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5
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Xue S, Tang Y, Kurnikov IV, Liao HJ, Li J, Chan NL, Kurnikova MG, Chang WC, Guo Y. Spectroscopic and computational studies of a bifunctional iron- and 2-oxoglutarate dependent enzyme, AsqJ. Methods Enzymol 2024; 704:199-232. [PMID: 39300648 PMCID: PMC11415609 DOI: 10.1016/bs.mie.2024.05.023] [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: 09/22/2024]
Abstract
Iron and 2-oxoglutarate dependent (Fe/2OG) enzymes exhibit an exceedingly broad reaction repertoire. The most prevalent reactivity is hydroxylation, but many other reactivities have also been discovered in recent years, including halogenation, desaturation, epoxidation, endoperoxidation, epimerization, and cyclization. To fully explore the reaction mechanisms that support such a diverse reactivities in Fe/2OG enzyme, it is necessary to utilize a multi-faceted research methodology, consisting of molecular probe design and synthesis, in vitro enzyme assay development, enzyme kinetics, spectroscopy, protein crystallography, and theoretical calculations. By using such a multi-faceted research approach, we have explored reaction mechanisms of desaturation and epoxidation catalyzed by a bi-functional Fe/2OG enzyme, AsqJ. Herein, we describe the experimental protocols and computational workflows used in our studies.
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Affiliation(s)
- Shan Xue
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Yijie Tang
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Igor V Kurnikov
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Hsuan-Jen Liao
- Institute of Biochemistry and Molecular Biology, College of Medicine, National (Taiwan) University, Taipei, Taiwan
| | - Jikun Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Nei-Li Chan
- Institute of Biochemistry and Molecular Biology, College of Medicine, National (Taiwan) University, Taipei, Taiwan.
| | - Maria G Kurnikova
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, United States.
| | - Wei-Chen Chang
- Department of Chemistry, North Carolina State University, Raleigh, NC, United States.
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, United States.
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6
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Vennelakanti V, Jeon M, Kulik HJ. How Do Differences in Electronic Structure Affect the Use of Vanadium Intermediates as Mimics in Nonheme Iron Hydroxylases? Inorg Chem 2024; 63:4997-5011. [PMID: 38428015 DOI: 10.1021/acs.inorgchem.3c04421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
We study active-site models of nonheme iron hydroxylases and their vanadium-based mimics using density functional theory to determine if vanadyl is a faithful structural mimic. We identify crucial structural and energetic differences between ferryl and vanadyl isomers owing to the differences in their ground electronic states, i.e., high spin (HS) for Fe and low spin (LS) for V. For the succinate cofactor bound to the ferryl intermediate, we predict facile interconversion between monodentate and bidentate coordination isomers for ferryl species but difficult rearrangement for vanadyl mimics. We study isomerization of the oxo intermediate between axial and equatorial positions and find the ferryl potential energy surface to be characterized by a large barrier of ca. 10 kcal/mol that is completely absent for the vanadyl mimic. This analysis reveals even starker contrasts between Fe and V in hydroxylases than those observed for this metal substitution in nonheme halogenases. Analysis of the relative bond strengths of coordinating carboxylate ligands for Fe and V reveals that all of the ligands show stronger binding to V than Fe owing to the LS ground state of V in contrast to the HS ground state of Fe, highlighting the limitations of vanadyl mimics of native nonheme iron hydroxylases.
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Affiliation(s)
- Vyshnavi Vennelakanti
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Mugyeom Jeon
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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7
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Paris JC, Hu S, Wen A, Weitz AC, Cheng R, Gee LB, Tang Y, Kim H, Vegas A, Chang WC, Elliott SJ, Liu P, Guo Y. An S=1 Iron(IV) Intermediate Revealed in a Non-Heme Iron Enzyme-Catalyzed Oxidative C-S Bond Formation. Angew Chem Int Ed Engl 2023; 62:e202309362. [PMID: 37640689 PMCID: PMC10592081 DOI: 10.1002/anie.202309362] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 08/11/2023] [Accepted: 08/28/2023] [Indexed: 08/31/2023]
Abstract
Ergothioneine (ESH) and ovothiol A (OSHA) are two natural thiol-histidine derivatives. ESH has been implicated as a longevity vitamin and OSHA inhibits the proliferation of hepatocarcinoma. The key biosynthetic step of ESH and OSHA in the aerobic pathways is the O2 -dependent C-S bond formation catalyzed by non-heme iron enzymes (e.g., OvoA in ovothiol biosynthesis), but due to the lack of identification of key reactive intermediate the mechanism of this novel reaction is unresolved. In this study, we report the identification and characterization of a kinetically competent S=1 iron(IV) intermediate supported by a four-histidine ligand environment (three from the protein residues and one from the substrate) in enabling C-S bond formation in OvoA from Methyloversatilis thermotoleran, which represents the first experimentally observed intermediate spin iron(IV) species in non-heme iron enzymes. Results reported in this study thus set the stage to further dissect the mechanism of enzymatic oxidative C-S bond formation in the OSHA biosynthesis pathway. They also afford new opportunities to study the structure-function relationship of high-valent iron intermediates supported by a histidine rich ligand environment.
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Affiliation(s)
- Jared C Paris
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, PA 15213, USA
| | - Sha Hu
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Aiwen Wen
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Andrew C Weitz
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Ronghai Cheng
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Leland B Gee
- LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025, USA
| | - Yijie Tang
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, PA 15213, USA
| | - Hyomin Kim
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Arturo Vegas
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Wei-Chen Chang
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Sean J Elliott
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Pinghua Liu
- Department of Chemistry, Boston University, 590 Commonwealth Ave., Boston, MA 02215, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, PA 15213, USA
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8
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Wang B, Lu Y, Cha L, Chen TY, Palacios PM, Li L, Guo Y, Chang WC, Chen C. Repurposing Iron- and 2-Oxoglutarate-Dependent Oxygenases to Catalyze Olefin Hydration. Angew Chem Int Ed Engl 2023; 62:e202311099. [PMID: 37639670 PMCID: PMC10592062 DOI: 10.1002/anie.202311099] [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: 08/01/2023] [Revised: 08/25/2023] [Accepted: 08/28/2023] [Indexed: 08/31/2023]
Abstract
Mononuclear nonheme iron(II) and 2-oxoglutarate (Fe/2OG)-dependent oxygenases and halogenases are known to catalyze a diverse set of oxidative reactions, including hydroxylation, halogenation, epoxidation, and desaturation in primary metabolism and natural product maturation. However, their use in abiotic transformations has mainly been limited to C-H oxidation. Herein, we show that various enzymes of this family, when reconstituted with Fe(II) or Fe(III), can catalyze Mukaiyama hydration-a redox neutral transformation. Distinct from the native reactions of the Fe/2OG enzymes, wherein oxygen atom transfer (OAT) catalyzed by an iron-oxo species is involved, this nonnative transformation proceeds through a hydrogen atom transfer (HAT) pathway in a 2OG-independent manner. Additionally, in contrast to conventional inorganic catalysts, wherein a dinuclear iron species is responsible for HAT, the Fe/2OG enzymes exploit a mononuclear iron center to support this reaction. Collectively, our work demonstrates that Fe/2OG enzymes have utility in catalysis beyond the current scope of catalytic oxidation.
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Affiliation(s)
- Bingnan Wang
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Yong Lu
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Lide Cha
- Department of Chemistry, NC State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA
| | - Tzu-Yu Chen
- Department of Chemistry, NC State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA
| | - Philip M Palacios
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | - Liping Li
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | - Wei-Chen Chang
- Department of Chemistry, NC State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA
| | - Chuo Chen
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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9
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Kastner DW, Nandy A, Mehmood R, Kulik HJ. Mechanistic Insights into Substrate Positioning That Distinguish Non-heme Fe(II)/α-Ketoglutarate-Dependent Halogenases and Hydroxylases. ACS Catal 2023. [DOI: 10.1021/acscatal.2c06241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- David W. Kastner
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Aditya Nandy
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Rimsha Mehmood
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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10
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Panth N, Wenger ES, Krebs C, Bollinger JM, Grossman RB. Synthesis of 6,6- and 7,7-difluoro-1-acetamidopyrrolizidines and their oxidation catalyzed by the nonheme Fe oxygenase LolO. Chembiochem 2022; 23:e202200081. [PMID: 35482316 DOI: 10.1002/cbic.202200081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/26/2022] [Indexed: 11/11/2022]
Abstract
LolO, a 2-oxoglutarate-dependent nonheme Fe oxygenase, catalyzes both the hydroxylation and cycloetherification of 1- exo -acetamidopyrrolizidine (AcAP), a pathway intermediate in the biosynthesis of the loline alkaloids. We have prepared fluorinated AcAP analogs to aid in continued mechanistic investigation of the unusual LolO-catalyzed cycloetherification step. LolO was able to first hydroxylate and then cycloetherify 6,6-difluoro-AcAP (prepared from N , O -protected 4-oxoproline), forming a difluorinated analog of N -acetylnorloline (NANL) and providing evidence for a cycloetherification mechanism involving a C(7) radical as opposed to a C(7) carbocation. By contrast, LolO was able to hydroxylate 7,7-difluoro-AcAP (prepared from 3-oxoproline) but failed to cycloetherify it, forming (1 R , 2 R , 8 S )-7,7-difluoro-2-hydroxy-AcAP as the sole product. Because it completely blocks the cycloetherification step, 7,7-difluoro-AcAP has the potential to become an important tool for accumulating and characterizing the LolO intermediate responsible for catalyzing cycloetherification of 2-hydroxy-AcAP.
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Affiliation(s)
- Nabin Panth
- University of Kentucky, Chemistry, UNITED STATES
| | | | - Carsten Krebs
- The Pennsylvania State University, Chemistry; Biochemistry and Molecular Biology, UNITED STATES
| | - J Martin Bollinger
- The Pennsylvania State University, Chemistry; Biochemistry and Molecular Biology, UNITED STATES
| | - Robert B Grossman
- University of Kentucky, Chemistry, Chemistry-Physics Building, 40506-0055, Lexington, UNITED STATES
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11
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Vennelakanti V, Mehmood R, Kulik HJ. Are Vanadium Intermediates Suitable Mimics in Non-Heme Iron Enzymes? An Electronic Structure Analysis. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vyshnavi Vennelakanti
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Rimsha Mehmood
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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12
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McBride MJ, Nair MA, Sil D, Slater JW, Neugebauer M, Chang MCY, Boal AK, Krebs C, Bollinger JM. Substrate-Triggered μ-Peroxodiiron(III) Intermediate in the 4-Chloro-l-Lysine-Fragmenting Heme-Oxygenase-like Diiron Oxidase (HDO) BesC: Substrate Dissociation from, and C4 Targeting by, the Intermediate. Biochemistry 2022; 61:689-702. [PMID: 35380785 PMCID: PMC9047515 DOI: 10.1021/acs.biochem.1c00774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The enzyme BesC from the β-ethynyl-l-serine biosynthetic pathway in Streptomyces cattleya fragments 4-chloro-l-lysine (produced from l-Lysine by BesD) to ammonia, formaldehyde, and 4-chloro-l-allylglycine and can analogously fragment l-Lys itself. BesC belongs to the emerging family of O2-activating non-heme-diiron enzymes with the "heme-oxygenase-like" protein fold (HDOs). Here, we show that the binding of l-Lys or an analogue triggers capture of O2 by the protein's diiron(II) cofactor to form a blue μ-peroxodiiron(III) intermediate analogous to those previously characterized in two other HDOs, the olefin-installing fatty acid decarboxylase, UndA, and the guanidino-N-oxygenase domain of SznF. The ∼5- and ∼30-fold faster decay of the intermediate in reactions with 4-thia-l-Lys and (4RS)-chloro-dl-lysine than in the reaction with l-Lys itself and the primary deuterium kinetic isotope effects (D-KIEs) on decay of the intermediate and production of l-allylglycine in the reaction with 4,4,5,5-[2H4]-l-Lys suggest that the peroxide intermediate or a reversibly connected successor complex abstracts a hydrogen atom from C4 to enable olefin formation. Surprisingly, the sluggish substrate l-Lys can dissociate after triggering intermediate formation, thereby allowing one of the better substrates to bind and react. The structure of apo BesC and the demonstrated linkage between Fe(II) and substrate binding suggest that the triggering event involves an induced ordering of ligand-providing helix 3 (α3) of the conditionally stable HDO core. As previously suggested for SznF, the dynamic α3 also likely initiates the spontaneous degradation of the diiron(III) product cluster after decay of the peroxide intermediate, a trait emerging as characteristic of the nascent HDO family.
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Affiliation(s)
- Molly J. McBride
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mrutyunjay A. Nair
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Debangsu Sil
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jeffrey W. Slater
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Monica Neugebauer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
- Present address: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Michelle C. Y. Chang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
- Departments of Chemistry and of Molecular and Cell Biology, University of California, Berkeley, and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Amie K. Boal
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - J. Martin Bollinger
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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13
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Wu L, Wang Z, Cen Y, Wang B, Zhou J. Structural Insight into the Catalytic Mechanism of the Endoperoxide Synthase FtmOx1. Angew Chem Int Ed Engl 2022; 61:e202112063. [PMID: 34796596 DOI: 10.1002/anie.202112063] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Indexed: 11/11/2022]
Abstract
The 2-oxoglutarate (2OG)-dependent non-heme enzyme FtmOx1 catalyzes the endoperoxide biosynthesis of verruculogen. Although several mechanistic studies have been carried out, the catalytic mechanism of FtmOx1 is not well determined owing to the lack of a reliable complex structure of FtmOx1 with fumitremorgin B. Herein we provide the X-ray crystal structure of the ternary complex FtmOx1⋅2OG⋅fumitremorgin B at a resolution of 1.22 Å. Our structures show that the binding of fumitremorgin B induces significant compression of the active pocket and that Y68 is in close proximity to C26 of the substrate. Further MD simulation and QM/MM calculations support a CarC-like mechanism, in which Y68 acts as the H atom donor for quenching the C26-centered substrate radical. Our results are consistent with all available experimental data and highlight the importance of accurate complex structures in the mechanistic study of enzymatic catalysis.
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Affiliation(s)
- Lian Wu
- The Research Center of Chiral Drugs, Innovation Research Institute of Traditional Chinese Medicine (IRI), Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, University of Chinese Academy of Sciences, Shanghai, 200032, China
| | - Zhanfeng Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yixin Cen
- The Research Center of Chiral Drugs, Innovation Research Institute of Traditional Chinese Medicine (IRI), Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, University of Chinese Academy of Sciences, Shanghai, 200032, China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Jiahai Zhou
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
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14
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Wu L, Wang Z, Cen Y, Wang B, Zhou J. Structural Insight into the Catalytic Mechanism of the Endoperoxide Synthase FtmOx1. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Lian Wu
- The Research Center of Chiral Drugs Innovation Research Institute of Traditional Chinese Medicine (IRI) Shanghai University of Traditional Chinese Medicine Shanghai 201203 China
- Key Laboratory of Synthetic Biology CAS Center for Excellence in Molecular Plant Sciences University of Chinese Academy of Sciences Shanghai 200032 China
| | - Zhanfeng Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Yixin Cen
- The Research Center of Chiral Drugs Innovation Research Institute of Traditional Chinese Medicine (IRI) Shanghai University of Traditional Chinese Medicine Shanghai 201203 China
- Key Laboratory of Synthetic Biology CAS Center for Excellence in Molecular Plant Sciences University of Chinese Academy of Sciences Shanghai 200032 China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China
| | - Jiahai Zhou
- CAS Key Laboratory of Quantitative Engineering Biology Shenzhen Institute of Synthetic Biology Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China
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15
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Fukuzumi S, Lee Y, Nam W. Deuterium kinetic isotope effects as redox mechanistic criterions. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12417] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Shunichi Fukuzumi
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
- Faculty of Science and Engineering Meijo University Nagoya Aichi Japan
| | - Yong‐Min Lee
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
- Research Institute for Basic Sciences Ewha Womans University Seoul Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
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16
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Usher ET, Namitz KEW, Cosgrove MS, Showalter SA. Probing multiple enzymatic methylation events in real time with NMR spectroscopy. Biophys J 2021; 120:4710-4721. [PMID: 34592262 PMCID: PMC8595733 DOI: 10.1016/j.bpj.2021.09.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/23/2021] [Accepted: 09/23/2021] [Indexed: 11/25/2022] Open
Abstract
Post-translational modification (PTM) of proteins is of critical importance to the regulation of many cellular processes in eukaryotic organisms. One of the most well-studied protein PTMs is methylation, wherein an enzyme catalyzes the transfer of a methyl group from a cofactor to a lysine or arginine side chain. Lysine methylation is especially abundant in the histone tails and is an important marker for denoting active or repressed genes. Given their relevance to transcriptional regulation, the study of methyltransferase function through in vitro experiments is an important stepping stone toward understanding the complex mechanisms of regulated gene expression. To date, most methyltransferase characterization strategies rely on the use of radioactive cofactors, detection of a methyl transfer byproduct, or discontinuous-type assays. Although such methods are suitable for some applications, information about multiple methylation events and kinetic intermediates is often lost. Herein, we describe the use of two-dimensional NMR to monitor mono-, di-, and trimethylation in a single reaction tube. To do so, we incorporated 13C into the donor methyl group of the enzyme cofactor S-adenosyl methionine. In this way, we may study enzymatic methylation by monitoring the appearance of distinct resonances corresponding to mono-, di-, or trimethyl lysine without the need to isotopically enrich the substrate. To demonstrate the capabilities of this method, we evaluated the activity of three lysine methyltransferases, Set7, MWRAD2 (MLL1 complex), and PRDM9, toward the histone H3 tail. We monitored mono- or multimethylation of histone H3 tail at lysine 4 through sequential short two-dimensional heteronuclear single quantum coherence experiments and fit the resulting progress curves to first-order kinetic models. In summary, NMR detection of PTMs in one-pot, real-time reaction using facile cofactor isotopic enrichment shows promise as a method toward understanding the intricate mechanisms of methyltransferases and other enzymes.
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Affiliation(s)
- Emery T Usher
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology
| | - Kevin E W Namitz
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania
| | - Michael S Cosgrove
- SUNY Upstate Medical University, Department of Biochemistry and Molecular Biology, Syracuse, New York
| | - Scott A Showalter
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania.
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17
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Valdez-Moreira JA, Beagan DM, Yang H, Telser J, Hoffman BM, Pink M, Carta V, Smith JM. Hydrocarbon Oxidation by an Exposed, Multiply Bonded Iron(III) Oxo Complex. ACS CENTRAL SCIENCE 2021; 7:1751-1755. [PMID: 34729418 PMCID: PMC8554833 DOI: 10.1021/acscentsci.1c00890] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Indexed: 06/10/2023]
Abstract
The iron oxo unit, [Fe=O] n+ is a critical intermediate in biological oxidation reactions. While its higher oxidation states are well studied, relatively little is known about the least-oxidized form [FeIII=O]+. Here, the thermally stable complex PhB(AdIm)3Fe=O has been structurally, spectroscopically, and computationally characterized as a bona fide iron(III) oxo. An unusually short Fe-O bond length is consistent with iron-oxygen multiple bond character and is supported by electronic structure calculations. The complex is thermally stable yet is able to perform hydrocarbon oxidations, facilitating both C-O bond formation and dehydrogenation reactions.
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Affiliation(s)
- Juan A. Valdez-Moreira
- Department
of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington Indiana 47405, United States
| | - Daniel M. Beagan
- Department
of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington Indiana 47405, United States
| | - Hao Yang
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Joshua Telser
- Department
of Biological, Physical and Health Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - Brian M. Hoffman
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Maren Pink
- Department
of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington Indiana 47405, United States
| | - Veronica Carta
- Department
of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington Indiana 47405, United States
| | - Jeremy M. Smith
- Department
of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington Indiana 47405, United States
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18
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Mehmood R, Vennelakanti V, Kulik HJ. Spectroscopically Guided Simulations Reveal Distinct Strategies for Positioning Substrates to Achieve Selectivity in Nonheme Fe(II)/α-Ketoglutarate-Dependent Halogenases. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03169] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Rimsha Mehmood
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Vyshnavi Vennelakanti
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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19
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Lee JL, Ross DL, Barman SK, Ziller JW, Borovik AS. C-H Bond Cleavage by Bioinspired Nonheme Metal Complexes. Inorg Chem 2021; 60:13759-13783. [PMID: 34491738 DOI: 10.1021/acs.inorgchem.1c01754] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The functionalization of C-H bonds is one of the most challenging transformations in synthetic chemistry. In biology, these processes are well-known and are achieved with a variety of metalloenzymes, many of which contain a single metal center within their active sites. The most well studied are those with Fe centers, and the emerging experimental data show that high-valent iron oxido species are the intermediates responsible for cleaving the C-H bond. This Forum Article describes the state of this field with an emphasis on nonheme Fe enzymes and current experimental results that provide insights into the properties that make these species capable of C-H bond cleavage. These parameters are also briefly considered in regard to manganese oxido complexes and Cu-containing metalloenzymes. Synthetic iron oxido complexes are discussed to highlight their utility as spectroscopic and mechanistic probes and reagents for C-H bond functionalization. Avenues for future research are also examined.
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Affiliation(s)
- Justin L Lee
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Dolores L Ross
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Suman K Barman
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - A S Borovik
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
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20
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Copeland RA, Davis KM, Shoda TKC, Blaesi EJ, Boal AK, Krebs C, Bollinger JM. An Iron(IV)-Oxo Intermediate Initiating l-Arginine Oxidation but Not Ethylene Production by the 2-Oxoglutarate-Dependent Oxygenase, Ethylene-Forming Enzyme. J Am Chem Soc 2021; 143:2293-2303. [PMID: 33522811 DOI: 10.1021/jacs.0c10923] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ethylene-forming enzyme (EFE) is an ambifunctional iron(II)- and 2-oxoglutarate-dependent (Fe/2OG) oxygenase. In its major (EF) reaction, it converts carbons 1, 2, and 5 of 2OG to CO2 and carbons 3 and 4 to ethylene, a four-electron oxidation drastically different from the simpler decarboxylation of 2OG to succinate mediated by all other Fe/2OG enzymes. EFE also catalyzes a minor reaction, in which the normal decarboxylation is coupled to oxidation of l-arginine (a required activator for the EF pathway), resulting in its conversion to l-glutamate semialdehyde and guanidine. Here we show that, consistent with precedent, the l-Arg-oxidation (RO) pathway proceeds via an iron(IV)-oxo (ferryl) intermediate. Use of 5,5-[2H2]-l-Arg slows decay of the ferryl complex by >16-fold, implying that RO is initiated by hydrogen-atom transfer (HAT) from C5. That this large substrate deuterium kinetic isotope effect has no impact on the EF:RO partition ratio implies that the same ferryl intermediate cannot be on the EF pathway; the pathways must diverge earlier. Consistent with this conclusion, the variant enzyme bearing the Asp191Glu ligand substitution accumulates ∼4 times as much of the ferryl complex as the wild-type enzyme and exhibits a ∼40-fold diminished EF:RO partition ratio. The selective detriment of this nearly conservative substitution to the EF pathway implies that it has unusually stringent stereoelectronic requirements. An active-site, like-charge guanidinium pair, which involves the l-Arg substrate/activator and is unique to EFE among four crystallographically characterized l-Arg-modifying Fe/2OG oxygenases, may serve to selectively stabilize the transition state leading to the unique EF branch.
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21
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Srnec M, Iyer SR, Dassama LMK, Park K, Wong SD, Sutherlin KD, Yoda Y, Kobayashi Y, Kurokuzu M, Saito M, Seto M, Krebs C, Bollinger JM, Solomon EI. Nuclear Resonance Vibrational Spectroscopic Definition of the Facial Triad Fe IV═O Intermediate in Taurine Dioxygenase: Evaluation of Structural Contributions to Hydrogen Atom Abstraction. J Am Chem Soc 2020; 142:18886-18896. [PMID: 33103886 DOI: 10.1021/jacs.0c08903] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The α-ketoglutarate (αKG)-dependent oxygenases catalyze a diverse range of chemical reactions using a common high-spin FeIV═O intermediate that, in most reactions, abstract a hydrogen atom from the substrate. Previously, the FeIV═O intermediate in the αKG-dependent halogenase SyrB2 was characterized by nuclear resonance vibrational spectroscopy (NRVS) and density functional theory (DFT) calculations, which demonstrated that it has a trigonal-pyramidal geometry with the scissile C-H bond of the substrate calculated to be perpendicular to the Fe-O bond. Here, we have used NRVS and DFT calculations to show that the FeIV═O complex in taurine dioxygenase (TauD), the αKG-dependent hydroxylase in which this intermediate was first characterized, also has a trigonal bipyramidal geometry but with an aspartate residue replacing the equatorial halide of the SyrB2 intermediate. Computational analysis of hydrogen atom abstraction by square pyramidal, trigonal bipyramidal, and six-coordinate FeIV═O complexes in two different substrate orientations (one more along [σ channel] and another more perpendicular [π channel] to the Fe-O bond) reveals similar activation barriers. Thus, both substrate approaches to all three geometries are competent in hydrogen atom abstraction. The equivalence in reactivity between the two substrate orientations arises from compensation of the promotion energy (electronic excitation within the d manifold) required to access the π channel by the significantly larger oxyl character present in the pπ orbital oriented toward the substrate, which leads to an earlier transition state along the C-H coordinate.
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Affiliation(s)
- Martin Srnec
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States.,J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 182 23, Czech Republic
| | - Shyam R Iyer
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States
| | - Laura M K Dassama
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Kiyoung Park
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States
| | - Shaun D Wong
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States
| | - Kyle D Sutherlin
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States
| | - Yoshitaka Yoda
- Japan Synchrotron Radiation Research Institute, Hyogo 679-5198, Japan
| | | | | | - Makina Saito
- Research Reactor Institute, Kyoto University, Osaka 590-0494, Japan
| | - Makoto Seto
- Research Reactor Institute, Kyoto University, Osaka 590-0494, Japan
| | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - J Martin Bollinger
- Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Edward I Solomon
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States
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22
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Mocniak LE, Elkin K, Bollinger JM. Lifetimes of the Aglycone Substrates of Specifier Proteins, the Autonomous Iron Enzymes That Dictate the Products of the Glucosinolate-Myrosinase Defense System in Brassica Plants. Biochemistry 2020; 59:2432-2441. [PMID: 32516526 DOI: 10.1021/acs.biochem.0c00358] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Specifier proteins (SPs) are components of the glucosinolate-myrosinase defense system found in plants of the order Brassicales (brassicas). Glucosinolates (GLSs) comprise at least 150 known S-(β-d-glucopyranosyl)thiohydroximate-O-sulfonate compounds, each with a distinguishing side chain linked to the central carbon. Following tissue injury, the enzyme myrosinase (MYR) promiscuously hydrolyzes the common thioglycosidic linkage of GLSs to produce unstable aglycone intermediates, which can readily undergo a Lossen-like rearrangement to the corresponding organoisothiocyanates. The known SPs share a common protein architecture but redirect the breakdown of aglycones to different stable products: epithionitrile (ESP), nitrile (NSP), or thiocyanate (TFP). The different effects of these products on brassica consumers motivate efforts to understand the defense response in chemical detail. Experimental analysis of SP mechanisms is challenged by the instability of the aglycones and would be facilitated by knowledge of their lifetimes. We developed a spectrophotometric method that we used to monitor the rearrangement reactions of the MYR-generated aglycones from nine GLSs, discovering that their half-lives (t1/2) vary by a factor of more than 50, from <3 to 150 s (22 °C). The t1/2 of the sinigrin-derived allyl aglycone (34 s), which can form the epithionitrile product (1-cyano-2,3-epithiopropane) in the presence of ESP, proved to be sufficient to enable spatial and temporal separation of the MYR and ESP reactions. The results confirm recent proposals that ESP is an autonomous iron-dependent enzyme that intercepts the unstable aglycone rather than a direct effector of MYR. Knowledge of aglycone lifetimes will enable elucidation of how the various SPs reroute aglycones to different products.
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Affiliation(s)
| | - Kyle Elkin
- Pasture Systems and Watershed Management Research Unit, United States Department of Agriculture Agricultural Research Service, Building 3702 Curtin Road, University Park, Pennsylvania 16802, United States
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23
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D'Amore L, Belpassi L, Klein JEMN, Swart M. Spin-resolved charge displacement analysis as an intuitive tool for the evaluation of cPCET and HAT scenarios. Chem Commun (Camb) 2020; 56:12146-12149. [DOI: 10.1039/d0cc04995f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The spin-resolved version of the charge displacement function is introduced as an intuitive tool for differentiating between hydrogen-atom transfer and concerted proton-coupled electron transfer.
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Affiliation(s)
- Lorenzo D'Amore
- IQCC and Dept. Chem
- Universitat de Girona
- Campus Montilivi
- 17003 Girona
- Spain
| | - Leonardo Belpassi
- Istituto di Scienze e Tecnologie Chimiche del CNR (SCITEC-CNR) c/o Università degli Studi di Perugia
- Via Elce di Sotto 8
- 06123 Perugia
- Italy
| | - Johannes E. M. N. Klein
- Molecular Inorganic Chemistry
- Stratingh Institute for Chemistry
- Faculty of Science and Engineering
- University of Groningen
- Groningen
| | - Marcel Swart
- IQCC and Dept. Chem
- Universitat de Girona
- Campus Montilivi
- 17003 Girona
- Spain
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24
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Davis KM, Altmyer M, Martinie RJ, Schaperdoth I, Krebs C, Bollinger JM, Boal AK. Structure of a Ferryl Mimic in the Archetypal Iron(II)- and 2-(Oxo)-glutarate-Dependent Dioxygenase, TauD. Biochemistry 2019; 58:4218-4223. [PMID: 31503454 DOI: 10.1021/acs.biochem.9b00598] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Iron(II)- and 2-(oxo)-glutarate-dependent (Fe/2OG) oxygenases catalyze a diverse array of oxidation reactions via a common iron(IV)-oxo (ferryl) intermediate. Although the intermediate has been characterized spectroscopically, its short lifetime has precluded crystallograhic characterization. In solution, the ferryl was first observed directly in the archetypal Fe/2OG hydroxylase, taurine:2OG dioxygenase (TauD). Here, we substitute the iron cofactor of TauD with the stable vanadium(IV)-oxo (vanadyl) ion to obtain crystal structures mimicking the key ferryl complex. Intriguingly, whereas the structure of the TauD·(VIV-oxo)·succinate·taurine complex exhibits the expected orientation of the V≡O bond-trans to the His255 ligand and toward the C-H bond to be cleaved, in what has been termed the in-line configuration-the TauD·(VIV-oxo) binary complex is best modeled with its oxo ligand trans to Asp101. This off-line-like configuration is similar to one recently posited as a means to avoid hydroxylation in Fe/2OG enzymes that direct other outcomes, though neither has been visualized in an Fe/2OG structure to date. Whereas an off-line (trans to the proximal His) or off-line-like (trans to the carboxylate ligand) ferryl is unlikely to be important in the hydroxylation reaction of TauD, the observation that the ferryl may deviate from an in-line orientation in the absence of the primary substrate may explain the enzyme's mysterious self-hydroxylation behavior, should the oxo ligand lie trans to His99. This finding reinforces the potential for analogous functional off-line oxo configurations in halogenases, desaturases, and/or cyclases.
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25
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Dantignana V, Serrano-Plana J, Draksharapu A, Magallón C, Banerjee S, Fan R, Gamba I, Guo Y, Que L, Costas M, Company A. Spectroscopic and Reactivity Comparisons between Nonheme Oxoiron(IV) and Oxoiron(V) Species Bearing the Same Ancillary Ligand. J Am Chem Soc 2019; 141:15078-15091. [PMID: 31469954 DOI: 10.1021/jacs.9b05758] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work directly compares the spectroscopic and reactivity properties of an oxoiron(IV) and an oxoiron(V) complex that are supported by the same neutral tetradentate N-based PyNMe3 ligand. A complete spectroscopic characterization of the oxoiron(IV) species (2) reveals that this compound exists as a mixture of two isomers. The reactivity of the thermodynamically more stable oxoiron(IV) isomer (2b) is directly compared to that exhibited by the previously reported 1e--oxidized analogue [FeV(O)(OAc)(PyNMe3)]2+ (3). Our data indicates that 2b is 4 to 5 orders of magnitude slower than 3 in hydrogen atom transfer (HAT) from C-H bonds. The origin of this huge difference lies in the strength of the O-H bond formed after HAT by the oxoiron unit, the O-H bond derived from 3 being about 20 kcal·mol-1 stronger than that from 2b. The estimated bond strength of the FeIVO-H bond of 100 kcal·mol-1 is very close to the reported values for highly active synthetic models of compound I of cytochrome P450. In addition, this comparative study provides direct experimental evidence that the lifetime of the carbon-centered radical that forms after the initial HAT by the high valent oxoiron complex depends on the oxidation state of the nascent Fe-OH complex. Complex 2b generates long-lived carbon-centered radicals that freely diffuse in solution, while 3 generates short-lived caged radicals that rapidly form product C-OH bonds, so only 3 engages in stereoretentive hydroxylation reactions. Thus, the oxidation state of the iron center modulates not only the rate of HAT but also the rate of ligand rebound.
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Affiliation(s)
- Valeria Dantignana
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Joan Serrano-Plana
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Apparao Draksharapu
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Carla Magallón
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Saikat Banerjee
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Ruixi Fan
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Ilaria Gamba
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Yisong Guo
- Department of Chemistry , Carnegie Mellon University , 4400 Fifth Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
| | - Anna Company
- Institut de Química Computacional i Catàlisi (IQCC), Departament de Química , Universitat de Girona , C/M. Aurèlia Capmany 69 , 17003 Girona , Catalonia , Spain
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26
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Chekan JR, Ongpipattanakul C, Wright TR, Zhang B, Bollinger JM, Rajakovich LJ, Krebs C, Cicchillo RM, Nair SK. Molecular basis for enantioselective herbicide degradation imparted by aryloxyalkanoate dioxygenases in transgenic plants. Proc Natl Acad Sci U S A 2019; 116:13299-13304. [PMID: 31209034 PMCID: PMC6613135 DOI: 10.1073/pnas.1900711116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) is an active ingredient of thousands of commercial herbicides. Multiple species of bacteria degrade 2,4-D via a pathway initiated by the Fe(II) and α-ketoglutarate (Fe/αKG)-dependent aryloxyalkanoate dioxygenases (AADs). Recently, genes encoding 2 AADs have been deployed commercially in herbicide-tolerant crops. Some AADs can also inactivate chiral phenoxypropionate and aryloxyphenoxypropionate (AOPP) herbicides, albeit with varying substrate enantioselectivities. Certain AAD enzymes, such as AAD-1, have expanded utility in weed control systems by enabling the use of diverse modes of action with a single trait. Here, we report 1) the use of a genomic context-based approach to identify 59 additional members of the AAD class, 2) the biochemical characterization of AAD-2 from Bradyrhizobium diazoefficiens USDA 110 as a catalyst to degrade (S)-stereoisomers of chiral synthetic auxins and AOPP herbicides, 3) spectroscopic data that demonstrate the canonical ferryl complex in the AAD-1 reaction, and 4) crystal structures of representatives of the AAD class. Structures of AAD-1, an (R)-enantiomer substrate-specific enzyme, in complexes with a phenoxypropionate synthetic auxin or with AOPP herbicides and of AAD-2, which has the opposite (S)-enantiomeric substrate specificity, reveal the structural basis for stereoselectivity and provide insights into a common catalytic mechanism.
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Affiliation(s)
- Jonathan R Chekan
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | | | - Terry R Wright
- Corteva Agriscience, Agriculture Division of DowDuPont, Indianapolis, IN 46268
| | - Bo Zhang
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - J Martin Bollinger
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Lauren J Rajakovich
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802
| | - Robert M Cicchillo
- Corteva Agriscience, Agriculture Division of DowDuPont, Indianapolis, IN 46268
| | - Satish K Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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27
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Xue J, Lu J, Lai W. Mechanistic insights into a non-heme 2-oxoglutarate-dependent ethylene-forming enzyme: selectivity of ethylene-formation versusl-Arg hydroxylation. Phys Chem Chem Phys 2019; 21:9957-9968. [PMID: 31041955 DOI: 10.1039/c9cp00794f] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The ethylene-forming enzyme (EFE) is a unique member of the Fe(ii)- and 2-oxoglutarate-dependent (Fe/2OG) oxygenases. It converts 2OG into ethylene plus three CO2 molecules (ethylene-forming reaction) and also catalyzes the C5 hydroxylation of l-arginine coupled to the oxidative decarboxylation of 2OG (l-Arg hydroxylation reaction). To uncover the mechanisms of the dual transformations by EFE, quantum mechanical/molecular mechanical (QM/MM) calculations were carried out. Based on the results, a branched mechanism was proposed. An FeII-peroxysuccinate complex with a dissociated CO2 generated through the nucleophilic attack of the superoxo moiety of the Fe-O2 species on the keto carbon of 2OG is the key common intermediate in both reactions. A competition between the subsequent CO2 insertion (a key step in the ethylene-forming pathway) and the O-O bond cleavage (leading to the formation of succinate) governs the product selectivity. The calculated reaction barriers suggested that the CO2 insertion is favored over the O-O bond cleavage. This is consistent with the product preference observed in experiments. By comparison with the results of AsqJ (an Fe/2OG oxygenase that leads to substrate oxidation exclusively), the protein environment was found to be crucial for the selectivity. Further calculations demonstrated that the local electric field of the protein environment in EFE promotes ethylene formation by acting as a charge template, exemplifying the importance of the electrostatic interaction in enzyme catalysis. These findings offer mechanistic insights into the EFE catalysis and provide important clues for better understanding the unique ethylene-forming capability of EFE compared with other Fe/2OG oxygenases.
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Affiliation(s)
- Junqin Xue
- Department of Chemistry, Renmin University of China, Beijing, 100872, China.
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28
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Davidson M, McNamee M, Fan R, Guo Y, Chang WC. Repurposing Nonheme Iron Hydroxylases To Enable Catalytic Nitrile Installation through an Azido Group Assistance. J Am Chem Soc 2019; 141:3419-3423. [PMID: 30759343 DOI: 10.1021/jacs.8b13906] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Three mononuclear nonheme iron and 2-oxoglutarate dependent enzymes, l-Ile 4-hydroxylase, l-Leu 5-hydroxylase and polyoxin dihydroxylase, are previously reported to catalyze the hydroxylation of l-isoleucine, l-leucine, and l-α-amino-δ-carbamoylhydroxyvaleric acid (ACV). In this study, we showed that these enzymes can accommodate leucine isomers and catalyze regiospecific hydroxylation. On the basis of these results, as a proof-of-concept, we demonstrated that the outcome of the reaction can be redirected by installation of an assisting group within the substrate. Specifically, instead of canonical hydroxylation, these enzymes can catalyze non-native nitrile group installation when an azido group is introduced. The reaction is likely to proceed through C-H bond activation by an Fe(IV)-oxo species, followed by azido-directed C≡N bond formation. These results offer a unique opportunity to investigate and expand the reaction repertoire of Fe/2OG enzymes.
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Affiliation(s)
- Madison Davidson
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Meredith McNamee
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Ruixi Fan
- Department of Chemistry , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Yisong Guo
- Department of Chemistry , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Wei-Chen Chang
- Department of Chemistry , North Carolina State University , Raleigh , North Carolina 27695 , United States
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29
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Miska A, Schurr D, Rinke G, Dittmeyer R, Schindler S. From model compounds to applications: Kinetic studies on the activation of dioxygen using an iron complex in a SuperFocus mixer. Chem Eng Sci 2018. [DOI: 10.1016/j.ces.2018.05.064] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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Andris E, Navrátil R, Jašík J, Puri M, Costas M, Que L, Roithová J. Trapping Iron(III)-Oxo Species at the Boundary of the "Oxo Wall": Insights into the Nature of the Fe(III)-O Bond. J Am Chem Soc 2018; 140:14391-14400. [PMID: 30336001 DOI: 10.1021/jacs.8b08950] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Terminal non-heme iron(IV)-oxo compounds are among the most powerful and best studied oxidants of strong C-H bonds. In contrast to the increasing number of such complexes (>80 thus far), corresponding one-electron-reduced derivatives are much rarer and presumably less stable, and only two iron(III)-oxo complexes have been characterized to date, both of which are stabilized by hydrogen-bonding interactions. Herein we have employed gas-phase techniques to generate and identify a series of terminal iron(III)-oxo complexes, all without built-in hydrogen bonding. Some of these complexes exhibit ∼70 cm-1 decrease in ν(Fe-O) frequencies expected for a half-order decrease in bond order upon one-electron reduction to an S = 5/2 center, while others have ν(Fe-O) frequencies essentially unchanged from those of their parent iron(IV)-oxo complexes. The latter result suggests that the added electron does not occupy a d orbital with Fe═O antibonding character, requiring an S = 3/2 spin assignment for the nascent FeIII-O- species. In the latter cases, water is found to hydrogen bond to the FeIII-O- unit, resulting in a change from quartet to sextet spin state. Reactivity studies also demonstrate the extraordinary basicity of these iron(III)-oxo complexes. Our observations show that metal-oxo species at the boundary of the "Oxo Wall" are accessible, and the data provide a lead to detect iron(III)-oxo intermediates in biological and biomimetic reactions.
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Affiliation(s)
- Erik Andris
- Department of Organic Chemistry, Faculty of Science , Charles University , Hlavova 2030/8 , 128 43 Prague 2 , Czech Republic
| | - Rafael Navrátil
- Department of Organic Chemistry, Faculty of Science , Charles University , Hlavova 2030/8 , 128 43 Prague 2 , Czech Republic
| | - Juraj Jašík
- Department of Organic Chemistry, Faculty of Science , Charles University , Hlavova 2030/8 , 128 43 Prague 2 , Czech Republic
| | - Mayank Puri
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Miquel Costas
- Departament de Quimica and Institute of Computational Chemistry and Catalysis (IQCC) , University of Girona , Campus Montilivi , Girona 17071 , Spain
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Jana Roithová
- Department of Organic Chemistry, Faculty of Science , Charles University , Hlavova 2030/8 , 128 43 Prague 2 , Czech Republic.,Institute for Molecules and Materials , Radboud University , Heyendaalseweg 135 , 6525 AJ Nijmegen , Netherlands
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31
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Klein JEMN, Knizia G. cPCET versus HAT: A Direct Theoretical Method for Distinguishing X-H Bond-Activation Mechanisms. Angew Chem Int Ed Engl 2018; 57:11913-11917. [PMID: 30019800 PMCID: PMC6175160 DOI: 10.1002/anie.201805511] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Indexed: 12/12/2022]
Abstract
Proton‐coupled electron transfer (PCET) events play a key role in countless chemical transformations, but they come in many physical variants which are hard to distinguish experimentally. While present theoretical approaches to treat these events are mostly based on physical rate coefficient models of various complexity, it is now argued that it is both feasible and fruitful to directly analyze the electronic N‐electron wavefunctions of these processes along their intrinsic reaction coordinate (IRC). In particular, for model systems of lipoxygenase and the high‐valent oxoiron(IV) intermediate TauD‐J it is shown that by invoking the intrinsic bond orbital (IBO) representation of the wavefunction, the common boundary cases of hydrogen atom transfer (HAT) and concerted PCET (cPCET) can be directly and unambiguously distinguished in a straightforward manner.
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Affiliation(s)
- Johannes E M N Klein
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Gerald Knizia
- Department of Chemistry, Pennsylvania State University, 401A Chemistry Bldg, University Park, PA, 16802, USA
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32
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Klein JEMN, Knizia G. cPCET versus HAT: A Direct Theoretical Method for Distinguishing X-H Bond-Activation Mechanisms. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201805511] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Johannes E. M. N. Klein
- Molecular Inorganic Chemistry; Stratingh Institute for Chemistry; Faculty of Science and Engineering; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Gerald Knizia
- Department of Chemistry; Pennsylvania State University; 401A Chemistry Bldg University Park PA 16802 USA
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33
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Gao SS, Naowarojna N, Cheng R, Liu X, Liu P. Recent examples of α-ketoglutarate-dependent mononuclear non-haem iron enzymes in natural product biosyntheses. Nat Prod Rep 2018; 35:792-837. [PMID: 29932179 PMCID: PMC6093783 DOI: 10.1039/c7np00067g] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Covering: up to 2018 α-Ketoglutarate (αKG, also known as 2-oxoglutarate)-dependent mononuclear non-haem iron (αKG-NHFe) enzymes catalyze a wide range of biochemical reactions, including hydroxylation, ring fragmentation, C-C bond cleavage, epimerization, desaturation, endoperoxidation and heterocycle formation. These enzymes utilize iron(ii) as the metallo-cofactor and αKG as the co-substrate. Herein, we summarize several novel αKG-NHFe enzymes involved in natural product biosyntheses discovered in recent years, including halogenation reactions, amino acid modifications and tailoring reactions in the biosynthesis of terpenes, lipids, fatty acids and phosphonates. We also conducted a survey of the currently available structures of αKG-NHFe enzymes, in which αKG binds to the metallo-centre bidentately through either a proximal- or distal-type binding mode. Future structure-function and structure-reactivity relationship investigations will provide crucial information regarding how activities in this large class of enzymes have been fine-tuned in nature.
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Affiliation(s)
- Shu-Shan Gao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | | | - Ronghai Cheng
- Department of Chemistry, Boston University, Boston, MA 02215, USA.
| | - Xueting Liu
- Department of Chemistry, Boston University, Boston, MA 02215, USA. and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, MA 02215, USA.
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34
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Mechanisms of Bacterial Tolerance and Persistence in the Gastrointestinal and Respiratory Environments. Clin Microbiol Rev 2018; 31:31/4/e00023-18. [PMID: 30068737 DOI: 10.1128/cmr.00023-18] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pathogens that infect the gastrointestinal and respiratory tracts are subjected to intense pressure due to the environmental conditions of the surroundings. This pressure has led to the development of mechanisms of bacterial tolerance or persistence which enable microorganisms to survive in these locations. In this review, we analyze the general stress response (RpoS mediated), reactive oxygen species (ROS) tolerance, energy metabolism, drug efflux pumps, SOS response, quorum sensing (QS) bacterial communication, (p)ppGpp signaling, and toxin-antitoxin (TA) systems of pathogens, such as Escherichia coli, Salmonella spp., Vibrio spp., Helicobacter spp., Campylobacter jejuni, Enterococcus spp., Shigella spp., Yersinia spp., and Clostridium difficile, all of which inhabit the gastrointestinal tract. The following respiratory tract pathogens are also considered: Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Burkholderia cenocepacia, and Mycobacterium tuberculosis Knowledge of the molecular mechanisms regulating the bacterial tolerance and persistence phenotypes is essential in the fight against multiresistant pathogens, as it will enable the identification of new targets for developing innovative anti-infective treatments.
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35
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Dunham NP, Chang WC, Mitchell AJ, Martinie RJ, Zhang B, Bergman JA, Rajakovich LJ, Wang B, Silakov A, Krebs C, Boal AK, Bollinger JM. Two Distinct Mechanisms for C-C Desaturation by Iron(II)- and 2-(Oxo)glutarate-Dependent Oxygenases: Importance of α-Heteroatom Assistance. J Am Chem Soc 2018; 140:7116-7126. [PMID: 29708749 PMCID: PMC5999578 DOI: 10.1021/jacs.8b01933] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydroxylation of aliphatic carbons by nonheme Fe(IV)-oxo (ferryl) complexes proceeds by hydrogen-atom (H•) transfer (HAT) to the ferryl and subsequent coupling between the carbon radical and Fe(III)-coordinated oxygen (termed rebound). Enzymes that use H•-abstracting ferryl complexes for other transformations must either suppress rebound or further process hydroxylated intermediates. For olefin-installing C-C desaturations, it has been proposed that a second HAT to the Fe(III)-OH complex from the carbon α to the radical preempts rebound. Deuterium (2H) at the second site should slow this step, potentially making rebound competitive. Desaturations mediated by two related l-arginine-modifying iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) oxygenases behave oppositely in this key test, implicating different mechanisms. NapI, the l-Arg 4,5-desaturase from the naphthyridinomycin biosynthetic pathway, abstracts H• first from C5 but hydroxylates this site (leading to guanidine release) to the same modest extent whether C4 harbors 1H or 2H. By contrast, an unexpected 3,4-desaturation of l-homoarginine (l-hArg) by VioC, the l-Arg 3-hydroxylase from the viomycin biosynthetic pathway, is markedly disfavored relative to C4 hydroxylation when C3 (the second hydrogen donor) harbors 2H. Anchimeric assistance by N6 permits removal of the C4-H as a proton in the NapI reaction, but, with no such assistance possible in the VioC desaturation, a second HAT step (from C3) is required. The close proximity (≤3.5 Å) of both l-hArg carbons to the oxygen ligand in an X-ray crystal structure of VioC harboring a vanadium-based ferryl mimic supports and rationalizes the sequential-HAT mechanism. The results suggest that, although the sequential-HAT mechanism is feasible, its geometric requirements may make competing hydroxylation unavoidable, thus explaining the presence of α-heteroatoms in nearly all native substrates for Fe/2OG desaturases.
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Affiliation(s)
- Noah P. Dunham
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
| | - Wei-chen Chang
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Andrew J. Mitchell
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
| | - Ryan J. Martinie
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Bo Zhang
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Jonathan A. Bergman
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
| | - Lauren J. Rajakovich
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
| | - Bo Wang
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Alexey Silakov
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Carsten Krebs
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - Amie K. Boal
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
| | - J. Martin Bollinger
- Department of Biochemistry and Molecular Biology, The Pennsylvania
State University, University Park, PA 16802
- Department of Chemistry, The Pennsylvania State University,
University Park, PA 16802
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36
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Pan J, Bhardwaj M, Zhang B, Chang WC, Schardl CL, Krebs C, Grossman RB, Bollinger JM. Installation of the Ether Bridge of Lolines by the Iron- and 2-Oxoglutarate-Dependent Oxygenase, LolO: Regio- and Stereochemistry of Sequential Hydroxylation and Oxacyclization Reactions. Biochemistry 2018. [PMID: 29537853 PMCID: PMC5895980 DOI: 10.1021/acs.biochem.8b00157] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The core of the loline
family of insecticidal alkaloids is the
bicyclic pyrrolizidine unit with an additional strained ether bridge
between carbons 2 and 7. Previously reported genetic and in
vivo biochemical analyses showed that the presumptive iron-
and 2-oxoglutarate-dependent (Fe/2OG) oxygenase, LolO, is required
for installation of the ether bridge upon the pathway intermediate,
1-exo-acetamidopyrrolizidine (AcAP). Here we show
that LolO is, in fact, solely responsible for this biosynthetic four-electron
oxidation. In sequential 2OG- and O2-consuming steps, LolO
removes hydrogens from C2 and C7 of AcAP to form both carbon–oxygen
bonds in N-acetylnorloline (NANL), the precursor
to all other lolines. When supplied with substoichiometric 2OG, LolO
only hydroxylates AcAP. At higher 2OG:AcAP ratios, the enzyme further
processes the alcohol to the tricyclic NANL. Characterization of the
alcohol intermediate by mass spectrometry and nuclear magnetic resonance
spectroscopy shows that it is 2-endo-hydroxy-1-exo-acetamidopyrrolizidine (2-endo-OH-AcAP).
Kinetic and spectroscopic analyses of reactions with site-specifically
deuteriated AcAP substrates confirm that the C2–H bond is cleaved
first and that the responsible intermediate is, as expected, an FeIV–oxo (ferryl) complex. Analyses of the loline products
from cultures fed with stereospecifically deuteriated AcAP precursors,
proline and aspartic acid, establish that LolO removes the endo hydrogens
from C2 and C7 and forms both new C–O bonds with retention
of configuration. These findings delineate the pathway to an important
class of natural insecticides and lay the foundation for mechanistic
dissection of the chemically challenging oxacyclization reaction.
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Affiliation(s)
- Juan Pan
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | | | - Bo Zhang
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Wei-Chen Chang
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | | | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | | | - J Martin Bollinger
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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37
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Song X, Lu J, Lai W. Mechanistic insights into dioxygen activation, oxygen atom exchange and substrate epoxidation by AsqJ dioxygenase from quantum mechanical/molecular mechanical calculations. Phys Chem Chem Phys 2018; 19:20188-20197. [PMID: 28726913 DOI: 10.1039/c7cp02687k] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Herein, we use in-protein quantum mechanical/molecular mechanical (QM/MM) calculations to elucidate the mechanism of dioxygen activation, oxygen atom exchange and substrate epoxidation processes by AsqJ, an FeII/α-ketoglutarate-dependent dioxygenase (α-KGD) using a 2-His-1-Asp facial triad. Our results demonstrated that the whole reaction proceeds through a quintet surface. The dioxygen activation by AsqJ leads to a quintet penta-coordinated FeIV-oxo species, which has a square pyramidal geometry with the oxo group trans to His134. This penta-coordinated FeIV-oxo species is not the reactive one in the substrate epoxidation reaction since its oxo group is pointing away from the target C[double bond, length as m-dash]C bond. Instead, it can undergo the oxo group isomerization followed by water binding or the water binding followed by oxygen atom exchange to form the reactive hexa-coordinated FeIV-oxo species with the oxo group trans to His211. The calculated parameters of Mössbauer spectra for this hexa-coordinated FeIV-oxo intermediate are in excellent agreement with the experimental values, suggesting that it is most likely the experimentally trapped species. The calculated energetics indicated that the rate-limiting step is the substrate C[double bond, length as m-dash]C bond activation. This work improves our understanding of the dioxygen activation by α-KGD and provides important structural information about the reactive FeIV-oxo species.
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Affiliation(s)
- Xudan Song
- Department of Chemistry, Renmin University of China, Beijing, 100872, China.
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38
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Liao HJ, Li J, Huang JL, Davidson M, Kurnikov I, Lin TS, Lee JL, Kurnikova M, Guo Y, Chan NL, Chang WC. Insights into the Desaturation of Cyclopeptin and its C3 Epimer Catalyzed by a non-Heme Iron Enzyme: Structural Characterization and Mechanism Elucidation. Angew Chem Int Ed Engl 2018; 57:1831-1835. [PMID: 29314482 DOI: 10.1002/anie.201710567] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/04/2017] [Indexed: 11/08/2022]
Abstract
AsqJ, an iron(II)- and 2-oxoglutarate-dependent enzyme found in viridicatin-type alkaloid biosynthetic pathways, catalyzes sequential desaturation and epoxidation to produce cyclopenins. Crystal structures of AsqJ bound to cyclopeptin and its C3 epimer are reported. Meanwhile, a detailed mechanistic study was carried out to decipher the desaturation mechanism. These findings suggest that a pathway involving hydrogen atom abstraction at the C10 position of the substrate by a short-lived FeIV -oxo species and the subsequent formation of a carbocation or a hydroxylated intermediate is preferred during AsqJ-catalyzed desaturation.
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Affiliation(s)
- Hsuan-Jen Liao
- Institute of Biochemistry and Molecular Biology, College of Medicine, National (Taiwan) University, Taipei, 100, Taiwan
| | - Jikun Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Jhih-Liang Huang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Madison Davidson
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Igor Kurnikov
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Te-Sheng Lin
- Institute of Biochemistry and Molecular Biology, College of Medicine, National (Taiwan) University, Taipei, 100, Taiwan
| | - Justin L Lee
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Maria Kurnikova
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Nei-Li Chan
- Institute of Biochemistry and Molecular Biology, College of Medicine, National (Taiwan) University, Taipei, 100, Taiwan
| | - Wei-Chen Chang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
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39
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Liao HJ, Li J, Huang JL, Davidson M, Kurnikov I, Lin TS, Lee JL, Kurnikova M, Guo Y, Chan NL, Chang WC. Insights into the Desaturation of Cyclopeptin and its C3 Epimer Catalyzed by a non-Heme Iron Enzyme: Structural Characterization and Mechanism Elucidation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201710567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Hsuan-Jen Liao
- Institute of Biochemistry and Molecular Biology; College of Medicine; National (Taiwan) University; Taipei 100 Taiwan
| | - Jikun Li
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Jhih-Liang Huang
- Department of Chemistry; North Carolina State University; Raleigh NC 27695 USA
| | - Madison Davidson
- Department of Chemistry; North Carolina State University; Raleigh NC 27695 USA
| | - Igor Kurnikov
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Te-Sheng Lin
- Institute of Biochemistry and Molecular Biology; College of Medicine; National (Taiwan) University; Taipei 100 Taiwan
| | - Justin L. Lee
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Maria Kurnikova
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Yisong Guo
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Nei-Li Chan
- Institute of Biochemistry and Molecular Biology; College of Medicine; National (Taiwan) University; Taipei 100 Taiwan
| | - Wei-chen Chang
- Department of Chemistry; North Carolina State University; Raleigh NC 27695 USA
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40
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Klein JEMN, Mandal D, Ching WM, Mallick D, Que L, Shaik S. Privileged Role of Thiolate as the Axial Ligand in Hydrogen Atom Transfer Reactions by Oxoiron(IV) Complexes in Shaping the Potential Energy Surface and Inducing Significant H-Atom Tunneling. J Am Chem Soc 2017; 139:18705-18713. [PMID: 29179544 DOI: 10.1021/jacs.7b11300] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An H/D kinetic isotope effect (KIE) of 80 is found at -20 °C for the oxidation of 9,10-dihydroanthracene by [FeIV(O)(TMCS)]+, a complex supported by the tetramethylcyclam (TMC) macrocycle with a tethered thiolate. This KIE value approaches that previously predicted by DFT calculations. Other [FeIV(O)(TMC)(anion)] complexes exhibit values of 20, suggesting that the thiolate ligand of [FeIV(O)(TMCS)]+ plays a unique role in facilitating tunneling. Calculations show that tunneling is most enhanced (a) when the bond asymmetry between C-H bond breaking and O-H bond formation in the transition state is minimized, and (b) when the electrostatic interactions in the O---H---C moiety are maximal. These two factors-which peak for the best electron donor, the thiolate ligand-afford a slim and narrow barrier through which the H-atom can tunnel most effectively.
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Affiliation(s)
- Johannes E M N Klein
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Debasish Mandal
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem , 91904 Jerusalem, Israel
| | - Wei-Min Ching
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Dibyendu Mallick
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem , 91904 Jerusalem, Israel
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Sason Shaik
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem , 91904 Jerusalem, Israel
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41
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Mitchell AJ, Dunham NP, Martinie RJ, Bergman JA, Pollock CJ, Hu K, Allen BD, Chang WC, Silakov A, Bollinger JM, Krebs C, Boal AK. Visualizing the Reaction Cycle in an Iron(II)- and 2-(Oxo)-glutarate-Dependent Hydroxylase. J Am Chem Soc 2017; 139:13830-13836. [PMID: 28823155 DOI: 10.1021/jacs.7b07374] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Iron(II)- and 2-(oxo)-glutarate-dependent oxygenases catalyze diverse oxidative transformations that are often initiated by abstraction of hydrogen from carbon by iron(IV)-oxo (ferryl) complexes. Control of the relative orientation of the substrate C-H and ferryl Fe-O bonds, primarily by direction of the oxo group into one of two cis-related coordination sites (termed inline and offline), may be generally important for control of the reaction outcome. Neither the ferryl complexes nor their fleeting precursors have been crystallographically characterized, hindering direct experimental validation of the offline hypothesis and elucidation of the means by which the protein might dictate an alternative oxo position. Comparison of high-resolution X-ray crystal structures of the substrate complex, an Fe(II)-peroxysuccinate ferryl precursor, and a vanadium(IV)-oxo mimic of the ferryl intermediate in the l-arginine 3-hydroxylase, VioC, reveals coordinated motions of active site residues that appear to control the intermediate geometries to determine reaction outcome.
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Affiliation(s)
- Andrew J Mitchell
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Noah P Dunham
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Ryan J Martinie
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Jonathan A Bergman
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Christopher J Pollock
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Kai Hu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,The Huck Institutes for the Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Benjamin D Allen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,The Huck Institutes for the Life Sciences, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Wei-Chen Chang
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Alexey Silakov
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - J Martin Bollinger
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Carsten Krebs
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Amie K Boal
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
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42
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Ching WM, Zhou A, Klein JEMN, Fan R, Knizia G, Cramer CJ, Guo Y, Que L. Characterization of the Fleeting Hydroxoiron(III) Complex of the Pentadentate TMC-py Ligand. Inorg Chem 2017; 56:11129-11140. [DOI: 10.1021/acs.inorgchem.7b01459] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Gerald Knizia
- Department
of Chemistry, Pennsylvania State University, 401A Chemistry Bldg; University Park, Pennsylvania 16802, United States
| | | | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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43
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Miska A, Norbury J, Lerch M, Schindler S. Dioxygen Activation: Potential Future Technical Applications in Reactive Bubbly Flows. Chem Eng Technol 2017. [DOI: 10.1002/ceat.201600684] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Andreas Miska
- Justus-Liebig-Universität; Institut für Anorganische und Analytische Chemie; Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Jonah Norbury
- Justus-Liebig-Universität; Institut für Anorganische und Analytische Chemie; Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Markus Lerch
- Justus-Liebig-Universität; Institut für Anorganische und Analytische Chemie; Heinrich-Buff-Ring 17 35392 Gießen Germany
| | - Siegfried Schindler
- Justus-Liebig-Universität; Institut für Anorganische und Analytische Chemie; Heinrich-Buff-Ring 17 35392 Gießen Germany
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44
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Ansari A, Ansari M, Singha A, Rajaraman G. Interplay of Electronic Cooperativity and Exchange Coupling in Regulating the Reactivity of Diiron(IV)-oxo Complexes towards C−H and O−H Bond Activation. Chemistry 2017; 23:10110-10125. [DOI: 10.1002/chem.201701059] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Azaj Ansari
- Department of Chemistry; CUH Haryana; Haryana 123031 India
| | | | - Asmita Singha
- Department of Chemistry; IIT Bombay; Mumbai 400076 India
| | - Gopalan Rajaraman
- Department of Chemistry; Indian Institute of Technology Bombay, Powai; Mumbai, Maharashtra 400076 India
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45
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Andris E, Navrátil R, Jašík J, Terencio T, Srnec M, Costas M, Roithová J. Chasing the Evasive Fe═O Stretch and the Spin State of the Iron(IV)-Oxo Complexes by Photodissociation Spectroscopy. J Am Chem Soc 2017; 139:2757-2765. [PMID: 28125220 DOI: 10.1021/jacs.6b12291] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We demonstrate the application of infrared photodissocation spectroscopy for determination of the Fe═O stretching frequencies of high-valent iron(IV)-oxo complexes [(L)Fe(O)(X)]2+/+ (L = TMC, N4Py, PyTACN, and X = CH3CN, CF3SO3, ClO4, CF3COO, NO3, N3). We show that the values determined by resonance Raman spectroscopy in acetonitrile solutions are on average 9 cm-1 red-shifted with respect to unbiased gas-phase values. Furthermore, we show the assignment of the spin state of the complexes based on the vibrational modes of a coordinated anion and compare reactivities of various iron(IV)-oxo complexes generated as dications or monocations (bearing an anionic ligand). The coordinated anions can drastically affect the reactivity of the complex and should be taken into account when comparing reactivities of complexes bearing different ligands. Comparison of reactivities of [(PyTACN)Fe(O)(X)]+ generated in different spin states and bearing different anionic ligands X revealed that the nature of anion influences the reactivity more than the spin state. The triflate and perchlorate ligands tend to stabilize the quintet state of [(PyTACN)Fe(O)(X)]+, whereas trifluoroacetate and nitrate stabilize the triplet state of the complex.
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Affiliation(s)
- Erik Andris
- Department of Organic Chemistry, Faculty of Science, Charles University , Hlavova 2030/8, 12843 Prague 2, Czech Republic
| | - Rafael Navrátil
- Department of Organic Chemistry, Faculty of Science, Charles University , Hlavova 2030/8, 12843 Prague 2, Czech Republic
| | - Juraj Jašík
- Department of Organic Chemistry, Faculty of Science, Charles University , Hlavova 2030/8, 12843 Prague 2, Czech Republic
| | - Thibault Terencio
- Department of Organic Chemistry, Faculty of Science, Charles University , Hlavova 2030/8, 12843 Prague 2, Czech Republic
| | - Martin Srnec
- J. Heyrovsky Institute of Physical Chemistry of the CAS , v.v i., Dolejškova 2155/3, 182 23 Prague 8, Czech Republic
| | - Miquel Costas
- Departament de Quimica and Institute of Computational Chemistry and Catalysis (IQCC), University of Girona , Campus Montilivi, Girona 17071, Spain
| | - Jana Roithová
- Department of Organic Chemistry, Faculty of Science, Charles University , Hlavova 2030/8, 12843 Prague 2, Czech Republic
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46
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Peck SC, Wang C, Dassama LMK, Zhang B, Guo Y, Rajakovich LJ, Bollinger JM, Krebs C, van der Donk WA. O-H Activation by an Unexpected Ferryl Intermediate during Catalysis by 2-Hydroxyethylphosphonate Dioxygenase. J Am Chem Soc 2017; 139:2045-2052. [PMID: 28092705 PMCID: PMC5302023 DOI: 10.1021/jacs.6b12147] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Activation
of O–H bonds by inorganic metal-oxo complexes
has been documented, but no cognate enzymatic process is known. Our
mechanistic analysis of 2-hydroxyethylphosphonate dioxygenase
(HEPD), which cleaves the C1–C2 bond of its substrate to afford
hydroxymethylphosphonate on the biosynthetic pathway to
the commercial herbicide phosphinothricin, uncovered an example
of such an O–H-bond-cleavage event. Stopped-flow UV–visible
absorption and freeze-quench Mössbauer experiments identified
a transient iron(IV)-oxo (ferryl) complex. Maximal accumulation of
the intermediate required both the presence of deuterium in the substrate
and, importantly, the use of 2H2O as solvent.
The ferryl complex forms and decays rapidly enough to be on the catalytic
pathway. To account for these unanticipated results, a new mechanism
that involves activation of an O–H bond by the ferryl complex
is proposed. This mechanism accommodates all available data on the
HEPD reaction.
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Affiliation(s)
- Spencer C Peck
- Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.,Institute for Genomic Biology, University of Illinois at Urbana-Champaign , 1206 West Gregory Drive, Urbana, Illinois 61801, United States
| | - Chen Wang
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Laura M K Dassama
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Bo Zhang
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Yisong Guo
- Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Lauren J Rajakovich
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - J Martin Bollinger
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Carsten Krebs
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Chemistry, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Wilfred A van der Donk
- Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.,Institute for Genomic Biology, University of Illinois at Urbana-Champaign , 1206 West Gregory Drive, Urbana, Illinois 61801, United States
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47
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Goswami A, Liu X, Cai W, Wyche TP, Bugni TS, Meurillon M, Peyrottes S, Perigaud C, Nonaka K, Rohr J, Van Lanen SG. Evidence that oxidative dephosphorylation by the nonheme Fe(II), α-ketoglutarate:UMP oxygenase occurs by stereospecific hydroxylation. FEBS Lett 2017; 591:468-478. [PMID: 28074470 DOI: 10.1002/1873-3468.12554] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 12/23/2016] [Accepted: 12/25/2016] [Indexed: 11/08/2022]
Abstract
LipL and Cpr19 are nonheme, mononuclear Fe(II)-dependent, α-ketoglutarate (αKG):UMP oxygenases that catalyze the formation of CO2 , succinate, phosphate, and uridine-5'-aldehyde, the last of which is a biosynthetic precursor for several nucleoside antibiotics that inhibit bacterial translocase I (MraY). To better understand the chemistry underlying this unusual oxidative dephosphorylation and establish a mechanistic framework for LipL and Cpr19, we report herein the synthesis of two biochemical probes-[1',3',4',5',5'-2 H]UMP and the phosphonate derivative of UMP-and their activity with both enzymes. The results are consistent with a reaction coordinate that proceeds through the loss of one 2 H atom of [1',3',4',5',5'-2 H]UMP and stereospecific hydroxylation geminal to the phosphoester to form a cryptic intermediate, (5'R)-5'-hydroxy-UMP. Thus, these enzyme catalysts can additionally be assigned as UMP hydroxylase-phospholyases.
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Affiliation(s)
- Anwesha Goswami
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Xiaodong Liu
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Wenlong Cai
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Thomas P Wyche
- Department of Pharmaceutical Sciences, University of Wisconsin-Madison, WI, USA
| | - Tim S Bugni
- Department of Pharmaceutical Sciences, University of Wisconsin-Madison, WI, USA
| | - Maïa Meurillon
- Nucleosides and Phosphorylated Effectors Team, IBMM, UMR5247 CNRS University Montpellier, France
| | - Suzanne Peyrottes
- Nucleosides and Phosphorylated Effectors Team, IBMM, UMR5247 CNRS University Montpellier, France
| | - Christian Perigaud
- Nucleosides and Phosphorylated Effectors Team, IBMM, UMR5247 CNRS University Montpellier, France
| | - Koichi Nonaka
- Biologics Technology Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., Gunma, Japan
| | - Jürgen Rohr
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Steven G Van Lanen
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
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48
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Kim Y, Mai BK, Park S. VTST/MT studies of the catalytic mechanism of C-H activation by transition metal complexes with [Cu 2(μ-O 2)], [Fe 2(μ-O 2)] and Fe(IV)-O cores based on DFT potential energy surfaces. J Biol Inorg Chem 2017; 22:321-338. [PMID: 28091753 DOI: 10.1007/s00775-017-1441-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/04/2017] [Indexed: 01/21/2023]
Abstract
High-valent Cu and Fe species, which are generated from dioxygen activation in metalloenzymes, carry out the functionalization of strong C-H bonds. Understanding the atomic details of the catalytic mechanism has long been one of the main objectives of bioinorganic chemistry. Large H/D kinetic isotope effects (KIEs) were observed in the C-H activation by high-valent non-heme Cu or Fe complexes in enzymes and their synthetic models. The H/D KIE depends significantly on the transition state properties, such as structure, energies, frequencies, and shape of the potential energy surface, when the tunneling effect is large. Therefore, theoretical predictions of kinetic parameters such as rate constants and KIEs can provide a reliable link between atomic-level quantum mechanical mechanisms and experiments. The accurate prediction of the tunneling effect is essential to reproduce the kinetic parameters. The rate constants and HD/KIE have been calculated using the variational transition-state theory including multidimensional tunneling based on DFT potential energy surfaces along the reaction coordinate. Excellent agreement was observed between the predicted and experimental results, which assures the validity of the DFT potential energy surfaces and, therefore, the proposed atomic-level mechanisms. The [Cu2(μ-O)2], [Fe2(μ-O)2], and Fe(IV)-oxo species were employed for C-H activation, and their role as catalysts was discussed at an atomic level.
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Affiliation(s)
- Yongho Kim
- Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, 1 Seochun-Dong, Giheung-Gu, Yongin-Si, Gyeonggi-Do, 446-701, Korea.
| | - Binh Khanh Mai
- Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, 1 Seochun-Dong, Giheung-Gu, Yongin-Si, Gyeonggi-Do, 446-701, Korea
| | - Sumin Park
- Department of Applied Chemistry and Institute of Natural Sciences, Kyung Hee University, 1 Seochun-Dong, Giheung-Gu, Yongin-Si, Gyeonggi-Do, 446-701, Korea
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49
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Abstract
The non-heme Fe enzymes are ubiquitous in nature and perform a wide range of functions involving O2 activation. These had been difficult to study relative to heme enzymes; however, spectroscopic methods that provide significant insight into the correlation of structure with function have now been developed. This Current Topics article summarizes both the molecular mechanism these enzymes use to control O2 activation in the presence of cosubstrates and the oxygen intermediates these reactions generate. Three types of O2 activation are observed. First, non-heme reactivity is shown to be different from heme chemistry where a low-spin FeIII-OOH non-heme intermediate directly reacts with substrate. Also, two subclasses of non-heme Fe enzymes generate high-spin FeIV═O intermediates that provide both σ and π frontier molecular orbitals that can control selectivity. Finally, for several subclasses of non-heme Fe enzymes, binding of the substrate to the FeII site leads to the one-electron reductive activation of O2 to an FeIII-superoxide capable of H atom abstraction and electrophilic attack.
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Affiliation(s)
- Edward I Solomon
- Department of Chemistry, Stanford University , Stanford, California 94305, United States.,SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | - Serra Goudarzi
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Kyle D Sutherlin
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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50
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A growing family of O2 activating dinuclear iron enzymes with key catalytic diiron(III)-peroxo intermediates: Biological systems and chemical models. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.05.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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