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De Tovar J, Leblay R, Wang Y, Wojcik L, Thibon-Pourret A, Réglier M, Simaan AJ, Le Poul N, Belle C. Copper-oxygen adducts: new trends in characterization and properties towards C-H activation. Chem Sci 2024; 15:10308-10349. [PMID: 38994420 PMCID: PMC11234856 DOI: 10.1039/d4sc01762e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 05/11/2024] [Indexed: 07/13/2024] Open
Abstract
This review summarizes the latest discoveries in the field of C-H activation by copper monoxygenases and more particularly by their bioinspired systems. This work first describes the recent background on copper-containing enzymes along with additional interpretations about the nature of the active copper-oxygen intermediates. It then focuses on relevant examples of bioinorganic synthetic copper-oxygen intermediates according to their nuclearity (mono to polynuclear). This includes a detailed description of the spectroscopic features of these adducts as well as their reactivity towards the oxidation of recalcitrant Csp3 -H bonds. The last part is devoted to the significant expansion of heterogeneous catalytic systems based on copper-oxygen cores (i.e. within zeolite frameworks).
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Affiliation(s)
- Jonathan De Tovar
- Université Grenoble-Alpes, CNRS, Département de Chimie Moléculaire Grenoble France
| | - Rébecca Leblay
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Institut des Sciences Moléculaires de Marseille Marseille France
| | - Yongxing Wang
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Institut des Sciences Moléculaires de Marseille Marseille France
| | - Laurianne Wojcik
- Université de Brest, Laboratoire de Chimie, Electrochimie Moléculaires et Chimie Analytique Brest France
| | | | - Marius Réglier
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Institut des Sciences Moléculaires de Marseille Marseille France
| | - A Jalila Simaan
- Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, Institut des Sciences Moléculaires de Marseille Marseille France
| | - Nicolas Le Poul
- Université de Brest, Laboratoire de Chimie, Electrochimie Moléculaires et Chimie Analytique Brest France
| | - Catherine Belle
- Université Grenoble-Alpes, CNRS, Département de Chimie Moléculaire Grenoble France
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2
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Wu Y, Zhao C, Su Y, Shaik S, Lai W. Mechanistic Insight into Peptidyl-Cysteine Oxidation by the Copper-Dependent Formylglycine-Generating Enzyme. Angew Chem Int Ed Engl 2023; 62:e202212053. [PMID: 36545867 DOI: 10.1002/anie.202212053] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/21/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
The copper-dependent formylglycine-generating enzyme (FGE) catalyzes the oxygen-dependent oxidation of specific peptidyl-cysteine residues to formylglycine. Our QM/MM calculations provide a very likely mechanism for this transformation. The reaction starts with dioxygen binding to the tris-thiolate CuI center to form a triplet CuII -superoxide complex. The rate-determining hydrogen atom abstraction involves a triplet-singlet crossing to form a CuII -OOH species that couples with the substrate radical, leading to a CuI -alkylperoxo intermediate. This is accompanied by proton transfer from the hydroperoxide to the S atom of the substrate via a nearby water molecule. The subsequent O-O bond cleavage is coupled with the C-S bond breaking that generates the formylglycine and a CuII -oxyl complex. Moreover, our results suggest that the aldehyde oxygen of the final product originates from O2 , which will be useful for future experimental work.
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Affiliation(s)
- Yao Wu
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing, 100872, China
| | - Cong Zhao
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing, 100872, China
| | - Yanzhuang Su
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing, 100872, China
| | - Sason Shaik
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Wenzhen Lai
- Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, Beijing, 100872, China
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3
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Functions and specificity of bacterial carbohydrate sulfatases targeting host glycans. Essays Biochem 2022; 67:429-442. [PMID: 36562177 PMCID: PMC10154612 DOI: 10.1042/ebc20220120] [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: 09/21/2022] [Revised: 11/08/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022]
Abstract
Sulfated host glycans (mucin O-glycans and glycosaminoglycans [GAGs]) are critical nutrient sources and colonisation factors for Bacteroidetes of the human gut microbiota (HGM); a complex ecosystem comprising essential microorganisms that coevolved with humans to serve important roles in pathogen protection, immune signalling, and host nutrition. Carbohydrate sulfatases are essential enzymes to access sulfated host glycans and are capable of exquisite regio- and stereo-selective substrate recognition. In these enzymes, the common recognition features of each subfamily are correlated with their genomic and environmental context. The exo-acting carbohydrate sulfatases are attractive drug targets amenable to small-molecule screening and subsequent engineering, and their high specificity will help elucidate the role of glycan sulfation in health and disease. Inhibition of carbohydrate sulfatases provides potential routes to control Bacteroidetes growth and to explore the influence of host glycan metabolism by Bacteroidetes on the HGM ecosystem. The roles of carbohydrate sulfatases from the HGM organism Bacteroides thetaiotaomicron and the soil isolated Pedobacter heparinus (P. heparinus) in sulfated host glycan metabolism are examined and contrasted, and the structural features underpinning glycan recognition and specificity explored.
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Moula G, Bag J, Bose M, Barman S, Pal K. Oxygen Activation by a Copper Complex with Sulfur-Only Coordination Relevant to the Formylglycine Generating Enzyme. Inorg Chem 2022; 61:6660-6671. [PMID: 35446020 DOI: 10.1021/acs.inorgchem.2c00746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synthesizing hydrosulfido Cu thiolate complexes is quite challenging. In this report, two new and rare hydrosulfido Cu thiolate complexes, [Et4N]2[(mnt)Cu-SH] (2, mnt = maleonitrile dithiolene = S2C2(CN)2) and [Et4N]3[(mnt)Cu-(μ-SH)-Cu(mnt)] (3), have been synthesized. Coordination sites and O2 activation by complex 2 resemble the formylglycine generating enzyme (FGE), an enzyme recently crystallographically characterized with sulfur-only coordination around Cu (three thiolate ligands). The function of this enzyme (and complex 2) is surprising because vulnerable thiolates should not be well suited for O2 activation rationally. Indeed, activation of oxygen by such an all-sulfur-coordinated Cu complex 2 is lacking in the literature. Aerial O2 (ambient O2 from the air) activation by complex 2 could proceed through a superoxide radical intermediate and a sulfur radical intermediate detected by resonance Raman (rR) spectroscopy and electron paramagnetic resonance (EPR) spectroscopy, respectively. The chemistry of 2 has been examined by its reactivity, crystal structure, and spectroscopic and cyclic voltammetric analyses. In addition, the results have been complemented with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations.
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Affiliation(s)
- Golam Moula
- Department of Chemistry, Rajabazar Science College, University of Calcutta, Kolkata 700009, West Bengal, India
| | - Jayanta Bag
- Department of Chemistry, Rajabazar Science College, University of Calcutta, Kolkata 700009, West Bengal, India
| | - Moumita Bose
- Department of Chemistry, Rajabazar Science College, University of Calcutta, Kolkata 700009, West Bengal, India
| | - Souvik Barman
- Department of Chemistry, Rajabazar Science College, University of Calcutta, Kolkata 700009, West Bengal, India
| | - Kuntal Pal
- Department of Chemistry, Rajabazar Science College, University of Calcutta, Kolkata 700009, West Bengal, India
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5
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Quek SY, Debnath S, Laxmi S, van Gastel M, Krämer T, England J. Sterically Stabilized End-On Superoxocopper(II) Complexes and Mechanistic Insights into Their Reactivity with O-H, N-H, and C-H Substrates. J Am Chem Soc 2021; 143:19731-19747. [PMID: 34783549 DOI: 10.1021/jacs.1c07837] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Instability of end-on superoxocopper(II) complexes, with respect to conversion to peroxo-bridged dicopper(II) complexes, has largely constrained their study to very low temperatures. This limits their kinetic capacity to oxidize substrates. In response, we have developed a series of bulky ligands, Ar3-TMPA (Ar = tpb, dpb, dtbpb), and used them to support copper(I) complexes that react with O2 to yield [CuII(η1-O2•-)(Ar3-TMPA)]+ species, which are stable against dimerization at all temperatures. Binding of O2 saturates at subambient temperatures and can be reversed by warming. The onset of oxygenation for the Ar = tpb and dpb systems is observed at 25 °C, and all three [CuII(η1-O2•-)(Ar3-TMPA)]+ complexes are stable against self-decay at temperatures of ≤-20 °C. This provides a wide temperature window for study of these complexes, which was exploited by performing extensive reaction kinetics measurements for [CuII(η1-O2•-)(tpb3-TMPA)]+ using a broad range of O-H, N-H, and C-H bond substrates. This includes correlation of second order rate constants (k2) versus oxidation potentials (Eox) for a range of phenols, construction of Eyring plots, and temperature-dependent kinetic isotope effect (KIE) measurements. The data obtained indicate that reaction with all substrates proceeds via H atom transfer (HAT), reaction with the phenols proceeds with significant charge transfer, and full tunneling of both H and D atoms occurs in the case of 1,2-diphenylhydrazine and 4-methoxy-2,6-di-tert-butylphenol. Oxidation of C-H bonds proved to be kinetically challenging, and whereas [CuII(η1-O2•-)(tpb3-TMPA)]+ can oxidize moderately strong O-H and N-H bonds, it is only able to oxidize very weak C-H bonds.
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Affiliation(s)
- Sebastian Y Quek
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Suman Debnath
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Shoba Laxmi
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Maurice van Gastel
- Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr D-45470, Germany
| | - Tobias Krämer
- Department of Chemistry, Maynooth University, Maynooth, Co. Kildare W23 F2H6, Ireland.,Hamilton Institute, Maynooth University, Maynooth, Co. Kildare W23 F2H6, Ireland
| | - Jason England
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,Department of Chemistry, University of Lincoln, Lincoln LN6 7TW, U.K
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Leisinger F, Miarzlou DA, Seebeck FP. Non-Coordinative Binding of O 2 at the Active Center of a Copper-Dependent Enzyme. Angew Chem Int Ed Engl 2021; 60:6154-6159. [PMID: 33245183 DOI: 10.1002/anie.202014981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Indexed: 12/28/2022]
Abstract
Molecular oxygen (O2 ) is a sustainable oxidation reagent. O2 is strongly oxidizing but kinetically stable and its final reaction product is water. For these reasons learning how to activate O2 and how to steer its reactivity along desired reaction pathways is a longstanding challenge in chemical research.[1] Activation of ground-state diradical O2 can occur either via conversion to singlet oxygen or by one-electron reduction to superoxide. Many enzymes facilitate activation of O2 by direct fomation of a metal-oxygen coordination complex concomitant with inner sphere electron transfer. The formylglycine generating enzyme (FGE) is an unusual mononuclear copper enzyme that appears to follow a different strategy. Atomic-resolution crystal structures of the precatalytic complex of FGE demonstrate that this enzyme binds O2 juxtaposed, but not coordinated to the catalytic CuI . Isostructural complexes that contain AgI instead of CuI or nitric oxide instead of O2 confirm that formation of the initial oxygenated complex of FGE does not depend on redox activity. A stepwise mechanism that decouples binding and activation of O2 is unprecedented for metal-dependent oxidases, but is reminiscent of flavin-dependent enzymes.
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Affiliation(s)
- Florian Leisinger
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4002, Basel, Switzerland
| | - Dzmitry A Miarzlou
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4002, Basel, Switzerland
| | - Florian P Seebeck
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4002, Basel, Switzerland
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7
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Leisinger F, Miarzlou DA, Seebeck FP. Non‐Coordinative Binding of O
2
at the Active Center of a Copper‐Dependent Enzyme. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Florian Leisinger
- Department of Chemistry University of Basel Mattenstrasse 24a 4002 Basel Switzerland
| | - Dzmitry A. Miarzlou
- Department of Chemistry University of Basel Mattenstrasse 24a 4002 Basel Switzerland
| | - Florian P. Seebeck
- Department of Chemistry University of Basel Mattenstrasse 24a 4002 Basel Switzerland
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8
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Lysosomal sulfatases: a growing family. Biochem J 2020; 477:3963-3983. [PMID: 33120425 DOI: 10.1042/bcj20200586] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/29/2020] [Accepted: 10/02/2020] [Indexed: 02/07/2023]
Abstract
Sulfatases constitute a family of enzymes that specifically act in the hydrolytic degradation of sulfated metabolites by removing sulfate monoesters from various substrates, particularly glycolipids and glycosaminoglycans. A common essential feature of all known eukaryotic sulfatases is the posttranslational modification of a critical cysteine residue in their active site by oxidation to formylglycine (FGly), which is mediated by the FGly-generating enzyme in the endoplasmic reticulum and is indispensable for catalytic activity. The majority of the so far described sulfatases localize intracellularly to lysosomes, where they act in different catabolic pathways. Mutations in genes coding for lysosomal sulfatases lead to an accumulation of the sulfated substrates in lysosomes, resulting in impaired cellular function and multisystemic disorders presenting as lysosomal storage diseases, which also cover the mucopolysaccharidoses and metachromatic leukodystrophy. Bioinformatics analysis of the eukaryotic genomes revealed, besides the well described and long known disease-associated sulfatases, additional genes coding for putative enzymes with sulfatases activity, including arylsulfatase G as well as the arylsulfatases H, I, J and K, respectively. In this article, we review current knowledge about lysosomal sulfatases with a special focus on the just recently characterized family members arylsulfatase G and arylsulfatase K.
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9
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Schlotawa L, Adang LA, Radhakrishnan K, Ahrens-Nicklas RC. Multiple Sulfatase Deficiency: A Disease Comprising Mucopolysaccharidosis, Sphingolipidosis, and More Caused by a Defect in Posttranslational Modification. Int J Mol Sci 2020; 21:E3448. [PMID: 32414121 PMCID: PMC7279497 DOI: 10.3390/ijms21103448] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/06/2020] [Accepted: 05/06/2020] [Indexed: 12/20/2022] Open
Abstract
Multiple sulfatase deficiency (MSD, MIM #272200) is an ultra-rare disease comprising pathophysiology and clinical features of mucopolysaccharidosis, sphingolipidosis and other sulfatase deficiencies. MSD is caused by impaired posttranslational activation of sulfatases through the formylglycine generating enzyme (FGE) encoded by the sulfatase modifying factor 1 (SUMF1) gene, which is mutated in MSD. FGE is a highly conserved, non-redundant ER protein that activates all cellular sulfatases by oxidizing a conserved cysteine in the active site of sulfatases that is necessary for full catalytic activity. SUMF1 mutations result in unstable, degradation-prone FGE that demonstrates reduced or absent catalytic activity, leading to decreased activity of all sulfatases. As the majority of sulfatases are localized to the lysosome, loss of sulfatase activity induces lysosomal storage of glycosaminoglycans and sulfatides and subsequent cellular pathology. MSD patients combine clinical features of all single sulfatase deficiencies in a systemic disease. Disease severity classifications distinguish cases based on age of onset and disease progression. A genotype- phenotype correlation has been proposed, biomarkers like excreted storage material and residual sulfatase activities do not correlate well with disease severity. The diagnosis of MSD is based on reduced sulfatase activities and detection of mutations in SUMF1. No therapy exists for MSD yet. This review summarizes the unique FGE/ sulfatase physiology, pathophysiology and clinical aspects in patients and their care and outlines future perspectives in MSD.
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Affiliation(s)
- Lars Schlotawa
- Department of Paediatrics and Adolescent Medicine, University Medical Centre Goettingen, 37075 Goettingen, Germany
| | - Laura A. Adang
- Division of Child Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
| | | | - Rebecca C. Ahrens-Nicklas
- Division of Human Genetics and Metabolism, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
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10
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Peng Q, Zang B, Zhao W, Li D, Ren J, Ji F, Jia L. Efficient continuous-flow aldehyde tag conversion using immobilized formylglycine generating enzyme. Catal Sci Technol 2020. [DOI: 10.1039/c9cy01856e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Immobilized formylglycine generating enzyme for efficient aldehyde tag conversion under continuous flow conditions.
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Affiliation(s)
- Qiang Peng
- Liaoning Key Laboratory of Molecular Recognition and Imaging
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Berlin Zang
- Liaoning Key Laboratory of Molecular Recognition and Imaging
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Wei Zhao
- Liaoning Key Laboratory of Molecular Recognition and Imaging
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Da Li
- Liaoning Key Laboratory of Molecular Recognition and Imaging
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Jun Ren
- Liaoning Key Laboratory of Molecular Recognition and Imaging
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Fangling Ji
- Liaoning Key Laboratory of Molecular Recognition and Imaging
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
| | - Lingyun Jia
- Liaoning Key Laboratory of Molecular Recognition and Imaging
- School of Life Science and Biotechnology
- Dalian University of Technology
- Dalian
- P. R. China
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11
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Diaz DE, Quist DA, Herzog AE, Schaefer AW, Kipouros I, Bhadra M, Solomon EI, Karlin KD. Impact of Intramolecular Hydrogen Bonding on the Reactivity of Cupric Superoxide Complexes with O−H and C−H Substrates. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201908471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel E. Diaz
- Chemistry DepartmentJohns Hopkins University Baltimore MD 21218 USA
| | - David A. Quist
- Chemistry DepartmentJohns Hopkins University Baltimore MD 21218 USA
| | - Austin E. Herzog
- Chemistry DepartmentJohns Hopkins University Baltimore MD 21218 USA
| | | | | | - Mayukh Bhadra
- Chemistry DepartmentJohns Hopkins University Baltimore MD 21218 USA
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12
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Alwan KB, Welch EF, Blackburn NJ. Catalytic M Center of Copper Monooxygenases Probed by Rational Design. Effects of Selenomethionine and Histidine Substitution on Structure and Reactivity. Biochemistry 2019; 58:4436-4446. [PMID: 31626532 DOI: 10.1021/acs.biochem.9b00823] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The M centers of the mononuclear monooxygenases peptidylglycine monooxygenase (PHM) and dopamine β-monooxygenase bind and activate dioxygen en route to substrate hydroxylation. Recently, we reported the rational design of a protein-based model in which the CusF metallochaperone was repurposed via a His to Met mutation to act as a structural and spectroscopic biomimic. The PHM M site exhibits a number of unusual attributes, including a His2Met ligand set, a fluxional Cu(I)-S(Met) bond, tight binding of exogenous ligands CO and N3-, and complete coupling of oxygen reduction to substrate hydroxylation even at extremely low turnover rates. In particular, mutation of the Met ligand to His completely eliminates the catalytic activity despite the propensity of CuI-His3 centers to bind and activate dioxygen in other metalloenzyme systems. Here, we further develop the CusF-based model to explore methionine variants in which Met is replaced by selenomethionine (SeM) and histidine. We examine the effects on coordinate structure and exogenous ligand binding via X-ray absorption spectroscopy and electron paramagnetic resonance and probe the consequences of mutations on redox chemistry via studies of the reduction by ascorbate and oxidation via molecular oxygen. The M-site model is three-coordinate in the Cu(I) state and binds CO to form a four-coordinate carbonyl. In the oxidized forms, the coordination changes to tetragonal five-coordinate with a long axial Met ligand that like the enzymes is undetectable at either the Cu or Se K edges. The EXAFS data at the Se K edge of the SeM variant provide unique information about the nature of the Cu-methionine bond that is likewise weak and fluxional. Kinetic studies document the sluggish reactivity of the Cu(I) complexes with molecular oxygen and rapid rates of reduction of the Cu(II) complexes by ascorbate, indicating a remarkable stability of the Cu(I) state in all three derivatives. The results show little difference between the Met ligand and its SeM and His congeners and suggest that the Met contributes to catalysis in ways that are more complex than simple perturbation of the redox chemistry. Overall, the results stimulate a critical re-examination of the canonical reaction mechanisms of the mononuclear copper monooxygenases.
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Affiliation(s)
- Katherine B Alwan
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Evan F Welch
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
| | - Ninian J Blackburn
- Department of Chemical Physiology and Biochemistry , Oregon Health & Sciences University , Portland , Oregon 97239 , United States
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13
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Diaz DE, Quist DA, Herzog AE, Schaefer AW, Kipouros I, Bhadra M, Solomon EI, Karlin KD. Impact of Intramolecular Hydrogen Bonding on the Reactivity of Cupric Superoxide Complexes with O-H and C-H Substrates. Angew Chem Int Ed Engl 2019; 58:17572-17576. [PMID: 31469942 DOI: 10.1002/anie.201908471] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/23/2019] [Indexed: 12/22/2022]
Abstract
The dioxygen reactivity of a series of TMPA-based copper(I) complexes (TMPA=tris(2-pyridylmethyl)amine), with and without secondary-coordination-sphere hydrogen-bonding moieties, was studied at -135 °C in 2-methyltetrahydrofuran (MeTHF). Kinetic stabilization of the H-bonded [( ( X 1 ) ( X 2 ) TMPA)CuII (O2 .- )]+ cupric superoxide species was achieved, and they were characterized by resonance Raman (rR) spectroscopy. The structures and physical properties of [( ( X 1 ) ( X 2 ) TMPA)CuII (N3 - )]+ azido analogues were compared, and the O2 .- reactivity of ligand-CuI complexes when an H-bonding moiety is replaced by a methyl group was contrasted. A drastic enhancement in the reactivity of the cupric superoxide towards phenolic substrates as well as oxidation of substrates possessing moderate C-H bond-dissociation energies is observed, correlating with the number and strength of the H-bonding groups.
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Affiliation(s)
- Daniel E Diaz
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - David A Quist
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Austin E Herzog
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
| | | | - Ioannis Kipouros
- Chemistry Department, Stanford University, Stanford, CA, 94305, USA
| | - Mayukh Bhadra
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Edward I Solomon
- Chemistry Department, Stanford University, Stanford, CA, 94305, USA
| | - Kenneth D Karlin
- Chemistry Department, Johns Hopkins University, Baltimore, MD, 21218, USA
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