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Fitzpatrick PF. The aromatic amino acid hydroxylases: Structures, catalysis, and regulation of phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase. Arch Biochem Biophys 2023; 735:109518. [PMID: 36639008 DOI: 10.1016/j.abb.2023.109518] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/01/2023] [Accepted: 01/06/2023] [Indexed: 01/12/2023]
Abstract
The aromatic amino acid hydroxylases phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase are non-heme iron enzymes that catalyze key physiological reactions. This review discusses the present understanding of the common catalytic mechanism of these enzymes and recent advances in understanding the relationship between their structures and their regulation.
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Affiliation(s)
- Paul F Fitzpatrick
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, 78229, USA.
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2
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Li M, Subedi BP, Fitzpatrick PF, Emerson JP. Thermodynamics of iron, tetrahydrobiopterin, and phenylalanine binding to phenylalanine hydroxylase from Chromobacterium violaceum. Arch Biochem Biophys 2022; 729:109378. [PMID: 35995215 PMCID: PMC10184773 DOI: 10.1016/j.abb.2022.109378] [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: 06/29/2022] [Revised: 08/13/2022] [Accepted: 08/16/2022] [Indexed: 11/02/2022]
Abstract
Phenylalanine hydroxylase (PheH) is a pterin-dependent, mononuclear nonheme iron(II) oxygenase that uses the oxidative power of O2 to hydroxylate phenylalanine to form tyrosine. PheH is a member of a superfamily of O2-activating enzymes that utilizes a common metal binding motif: the 2-His-1-carboxylate facial triad. Like most members of this superfamily, binding of substrates to PheH results in a reorganization of its active site to allow O2 activation. Exploring the energetics of each step before O2 activation can provide mechanistic insight into the initial steps that support the highly specific O2 activation pathway carried out by this metalloenzyme. Here the thermal stability of PheH and its substrate complexes were investigated under an anaerobic environment by using differential scanning calorimetry. In context with known binding constants for PheH, a thermodynamic cycle associated with iron(II), tetrahydrobiopterin (BH4), and phenylalanine binding to the active site was generated, showing a distinctive cooperativity between the binding of BH4 and Phe. The addition of phenylalanine and BH4 to PheH·Fe increased the stability of this enzyme (ΔTm of 8.5 (±0.7) °C with an associated δΔH of 43.0 (±2.9) kcal/mol). The thermodynamic data presented here gives insight into the complicated interactions between metal center, cofactor, and substrate, and how this interplay sets the stage for highly specific, oxidative C-H activation in this enzyme.
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Affiliation(s)
- Mingjie Li
- Department of Chemistry, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Bishnu P Subedi
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Paul F Fitzpatrick
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, 78229, USA.
| | - Joseph P Emerson
- Department of Chemistry, Mississippi State University, Mississippi State, MS, 39762, USA.
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3
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Cheng R, Weitz AC, Paris J, Tang Y, Zhang J, Song H, Naowarojna N, Li K, Qiao L, Lopez J, Grinstaff MW, Zhang L, Guo Y, Elliott S, Liu P. OvoA Mtht from Methyloversatilis thermotolerans ovothiol biosynthesis is a bifunction enzyme: thiol oxygenase and sulfoxide synthase activities. Chem Sci 2022; 13:3589-3598. [PMID: 35432880 PMCID: PMC8943887 DOI: 10.1039/d1sc05479a] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 02/24/2022] [Indexed: 01/03/2023] Open
Abstract
Mononuclear non-heme iron enzymes are a large class of enzymes catalyzing a wide-range of reactions. In this work, we report that a non-heme iron enzyme in Methyloversatilis thermotolerans, OvoAMtht, has two different activities, as a thiol oxygenase and a sulfoxide synthase. When cysteine is presented as the only substrate, OvoAMtht is a thiol oxygenase. In the presence of both histidine and cysteine as substrates, OvoAMtht catalyzes the oxidative coupling between histidine and cysteine (a sulfoxide synthase). Additionally, we demonstrate that both substrates and the active site iron's secondary coordination shell residues exert exquisite control over the dual activities of OvoAMtht (sulfoxide synthase vs. thiol oxygenase activities). OvoAMtht is an excellent system for future detailed mechanistic investigation on how metal ligands and secondary coordination shell residues fine-tune the iron-center electronic properties to achieve different reactivities. Modulation of OvoAMtht's dual activities: sulfoxide synthase and thiol oxygenase.![]()
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Affiliation(s)
- Ronghai Cheng
- 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
| | - Jared Paris
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 1521 USA
| | - Yijie Tang
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 1521 USA
| | - Jingyu Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology 130 Meilong Rd Shanghai 200237 China
| | - Heng Song
- Department of Chemistry, Boston University 590 Commonwealth Ave. Boston MA 02215 USA
| | - Nathchar Naowarojna
- Department of Chemistry, Boston University 590 Commonwealth Ave. Boston MA 02215 USA
| | - Kelin Li
- Department of Chemistry, Boston University 590 Commonwealth Ave. Boston MA 02215 USA
| | - Lu Qiao
- Department of Chemistry, Boston University 590 Commonwealth Ave. Boston MA 02215 USA
| | - Juan Lopez
- Department of Chemistry, Boston University 590 Commonwealth Ave. Boston MA 02215 USA
| | - Mark W Grinstaff
- Department of Chemistry, Boston University 590 Commonwealth Ave. Boston MA 02215 USA
| | - Lixin Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology 130 Meilong Rd Shanghai 200237 China
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 1521 USA
| | - Sean 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
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4
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Affiliation(s)
- Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) Universitat de Girona C/Mª Aurèlia Capmany 69 17003 Girona Catalonia Spain
| | - Anna Company
- Institut de Química Computacional i Catàlisi (IQCC) Universitat de Girona C/Mª Aurèlia Capmany 69 17003 Girona Catalonia Spain
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5
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McCracken J, Casey TM, Hausinger RP. 1H-HYSCORE Reveals Structural Details at the Fe(II) Active Site of Taurine:2-Oxoglutarate Dioxygenase. APPLIED MAGNETIC RESONANCE 2021; 52:971-994. [PMID: 35250178 PMCID: PMC8896577 DOI: 10.1007/s00723-020-01288-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/23/2020] [Accepted: 10/15/2020] [Indexed: 06/14/2023]
Abstract
Proton Hyperfine Sublevel Correlation (1H-HYSCORE) experiments have been used to probe the ligation structure of the Fe(II) active site of taurine:2-oxoglutarate dioxygenase (TauD), a non-heme Fe(II) hydroxylase. To facilitate Electron Paramagnetic Resonance (EPR) experiments, Fe(II) derivatives of the enzyme were studied using nitric oxide as a substitute for molecular oxygen. The addition of NO to the enzyme yields an S = 3/2 {FeNO}7 paramagnetic center characterized by nearly axial EPR spectra with g⊥ = 4 and g|| = 2. Using results from (i) an X-ray crystallographic study of TauD crystallized under anaerobic conditions in the presence of both cosubstrate 2-oxoglutarate and substrate taurine, (ii) a published theoretical description of the {FeNO}7 derivative of this form of the enzyme, and (iii) previous 2H-Electron Spin Echo Envelope Modulation (ESEEM) studies, we were able to assign the proton cross peaks detected in orientation-selected 1H-HYSCORE spectra. Discrete contributions from the protons of two coordinated histidine ligands were resolved. If substrate taurine is absent from the complex, orientation-selective HYSCORE spectra show cross peaks that are less resolved and when combined with information obtained from continuous wave EPR, support an alternate binding scheme for 2-oxoglutarate. HYSCORE studies of TauD in the absence of 2-oxoglutarate show additional 1H cross peaks that can be assigned to two distinct bound water molecules. In addition, 1H and 14N cross peaks that arise from the coordinated histidine side chains show a change in NO coordination for this species. For all of the TauD species, 1H hyperfine couplings and their orientations are sensitive to the detailed electronic structure of the {FeNO}7 center.
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Affiliation(s)
- John McCracken
- Department of Chemistry, Michigan State University, East Lansing, MI 48824
| | - Thomas M. Casey
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106
| | - Robert P. Hausinger
- Departments of Biochemistry and Molecular Biology, and Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
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6
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Direct coordination of pterin to Fe II enables neurotransmitter biosynthesis in the pterin-dependent hydroxylases. Proc Natl Acad Sci U S A 2021; 118:2022379118. [PMID: 33876764 PMCID: PMC8053929 DOI: 10.1073/pnas.2022379118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The pterin-dependent nonheme iron enzymes hydroxylate aromatic amino acids to perform the biosynthesis of neurotransmitters to maintain proper brain function. These enzymes activate oxygen using a pterin cofactor and an aromatic amino acid substrate bound to the FeII active site to form a highly reactive FeIV = O species that initiates substrate oxidation. In this study, using tryptophan hydroxylase, we have kinetically generated a pre-FeIV = O intermediate and characterized its structure as a FeII-peroxy-pterin species using absorption, Mössbauer, resonance Raman, and nuclear resonance vibrational spectroscopies. From parallel characterization of the pterin cofactor and tryptophan substrate-bound ternary FeII active site before the O2 reaction (including magnetic circular dichroism spectroscopy), these studies both experimentally define the mechanism of FeIV = O formation and demonstrate that the carbonyl functional group on the pterin is directly coordinated to the FeII site in both the ternary complex and the peroxo intermediate. Reaction coordinate calculations predict a 14 kcal/mol reduction in the oxygen activation barrier due to the direct binding of the pterin carbonyl to the FeII site, as this interaction provides an orbital pathway for efficient electron transfer from the pterin cofactor to the iron center. This direct coordination of the pterin cofactor enables the biological function of the pterin-dependent hydroxylases and demonstrates a unified mechanism for oxygen activation by the cofactor-dependent nonheme iron enzymes.
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7
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Beckmann F, Kass D, Keck M, Yelin S, Hoof S, Cula B, Herwig C, Krause KB, Ar D, Limberg C. High‐spin square planar iron(II) alkali metal siloxide complexes – influence of the alkali metal and reactivity towards O
2
and NO. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202100059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Fabian Beckmann
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Dustin Kass
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Matthias Keck
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Stefan Yelin
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Santina Hoof
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Beatrice Cula
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Christian Herwig
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Konstantin B. Krause
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Deniz Ar
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Christian Limberg
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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8
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Abstract
Fluorochemicals are a widely distributed class of compounds and have been utilized across a wide range of industries for decades. Given the environmental toxicity and adverse health threats of some fluorochemicals, the development of new methods for their decomposition is significant to public health. However, the carbon-fluorine (C-F) bond is among the most chemically robust bonds; consequently, the degradation of fluorinated hydrocarbons is exceptionally difficult. Here, metalloenzymes that catalyze the cleavage of this chemically challenging bond are reviewed. These enzymes include histidine-ligated heme-dependent dehaloperoxidase and tyrosine hydroxylase, thiolate-ligated heme-dependent cytochrome P450, and four nonheme oxygenases, namely, tetrahydrobiopterin-dependent aromatic amino acid hydroxylase, 2-oxoglutarate-dependent hydroxylase, Rieske dioxygenase, and thiol dioxygenase. While much of the literature regarding the aforementioned enzymes highlights their ability to catalyze C-H bond activation and functionalization, in many cases, the C-F bond cleavage has been shown to occur on fluorinated substrates. A copper-dependent laccase-mediated system representing an unnatural radical defluorination approach is also described. Detailed discussions on the structure-function relationships and catalytic mechanisms provide insights into biocatalytic defluorination, which may inspire drug design considerations and environmental remediation of halogenated contaminants.
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Affiliation(s)
- Yifan Wang
- Department of Chemistry, University of Texas at San Antonio, 1 UTSA Circle, San Antonio, TX 78249, USA.
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9
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Roatsch M, Hoffmann I, Abboud MI, Hancock RL, Tarhonskaya H, Hsu KF, Wilkins SE, Yeh TL, Lippl K, Serrer K, Moneke I, Ahrens TD, Robaa D, Wenzler S, Barthes NPF, Franz H, Sippl W, Lassmann S, Diederichs S, Schleicher E, Schofield CJ, Kawamura A, Schüle R, Jung M. The Clinically Used Iron Chelator Deferasirox Is an Inhibitor of Epigenetic JumonjiC Domain-Containing Histone Demethylases. ACS Chem Biol 2019; 14:1737-1750. [PMID: 31287655 DOI: 10.1021/acschembio.9b00289] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Fe(II)- and 2-oxoglutarate (2OG)-dependent JumonjiC domain-containing histone demethylases (JmjC KDMs) are "epigenetic eraser" enzymes involved in the regulation of gene expression and are emerging drug targets in oncology. We screened a set of clinically used iron chelators and report that they potently inhibit JMJD2A (KDM4A) in vitro. Mode of action investigations revealed that one compound, deferasirox, is a bona fide active site-binding inhibitor as shown by kinetic and spectroscopic studies. Synthesis of derivatives with improved cell permeability resulted in significant upregulation of histone trimethylation and potent cancer cell growth inhibition. Deferasirox was also found to inhibit human 2OG-dependent hypoxia inducible factor prolyl hydroxylase activity. Therapeutic effects of clinically used deferasirox may thus involve transcriptional regulation through 2OG oxygenase inhibition. Deferasirox might provide a useful starting point for the development of novel anticancer drugs targeting 2OG oxygenases and a valuable tool compound for investigations of KDM function.
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Affiliation(s)
- Martin Roatsch
- Institute of Pharmaceutical Sciences , Albert-Ludwigs-Universität Freiburg , Albertstraße 25 , 79104 Freiburg i.Br. , Germany
| | - Inga Hoffmann
- Institute of Pharmaceutical Sciences , Albert-Ludwigs-Universität Freiburg , Albertstraße 25 , 79104 Freiburg i.Br. , Germany
| | - Martine I Abboud
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Rebecca L Hancock
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Hanna Tarhonskaya
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Kuo-Feng Hsu
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Sarah E Wilkins
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Tzu-Lan Yeh
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Kerstin Lippl
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Kerstin Serrer
- Institute of Physical Chemistry , Albert-Ludwigs-Universität Freiburg , Albertstraße 21 , 79104 Freiburg i.Br. , Germany
| | - Isabelle Moneke
- Division of Cancer Research, Department of Thoracic Surgery, Medical Center-University of Freiburg, Faculty of Medicine , University of Freiburg , German Cancer Consortium (DKTK)-Partner Site Freiburg, Breisacher Straße 115 , 79106 Freiburg i.Br. , Germany
| | - Theresa D Ahrens
- Institute for Surgical Pathology, Medical Center and Faculty of Medicine , University of Freiburg , Breisacher Straße 115a , 79106 Freiburg i.Br. , Germany
| | - Dina Robaa
- Institute of Pharmacy , Martin-Luther-University Halle-Wittenberg , Wolfgang-Langenbeck-Straße 4 , 06120 Halle (Saale) , Germany
| | - Sandra Wenzler
- Institute of Pharmaceutical Sciences , Albert-Ludwigs-Universität Freiburg , Albertstraße 25 , 79104 Freiburg i.Br. , Germany
| | - Nicolas P F Barthes
- Institute of Pharmaceutical Sciences , Albert-Ludwigs-Universität Freiburg , Albertstraße 25 , 79104 Freiburg i.Br. , Germany
| | - Henriette Franz
- Central Clinical Research, Medical Center and Faculty of Medicine , University of Freiburg , Breisacher Straße 66 , 79106 Freiburg i.Br. , Germany
| | - Wolfgang Sippl
- Institute of Pharmacy , Martin-Luther-University Halle-Wittenberg , Wolfgang-Langenbeck-Straße 4 , 06120 Halle (Saale) , Germany
| | - Silke Lassmann
- Institute for Surgical Pathology, Medical Center and Faculty of Medicine , University of Freiburg , Breisacher Straße 115a , 79106 Freiburg i.Br. , Germany
| | - Sven Diederichs
- Division of Cancer Research, Department of Thoracic Surgery, Medical Center-University of Freiburg, Faculty of Medicine , University of Freiburg , German Cancer Consortium (DKTK)-Partner Site Freiburg, Breisacher Straße 115 , 79106 Freiburg i.Br. , Germany
- Division of RNA Biology & Cancer , German Cancer Research Center (DKFZ) , Im Neuenheimer Feld 280 , 69120 Heidelberg , Germany
| | - Erik Schleicher
- Institute of Physical Chemistry , Albert-Ludwigs-Universität Freiburg , Albertstraße 21 , 79104 Freiburg i.Br. , Germany
| | - Christopher J Schofield
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Akane Kawamura
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Roland Schüle
- Central Clinical Research, Medical Center and Faculty of Medicine , University of Freiburg , Breisacher Straße 66 , 79106 Freiburg i.Br. , Germany
| | - Manfred Jung
- Institute of Pharmaceutical Sciences , Albert-Ludwigs-Universität Freiburg , Albertstraße 25 , 79104 Freiburg i.Br. , Germany
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10
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Huang D, Zhang L, Yang JQ, Luo Y, Cui T, Du TT, Jiang XH. Evaluation on monoamine neurotransmitters changes in depression rats given with sertraline, meloxicam or/and caffeic acid. Genes Dis 2018; 6:167-175. [PMID: 31193976 PMCID: PMC6545449 DOI: 10.1016/j.gendis.2018.05.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/31/2018] [Indexed: 02/05/2023] Open
Abstract
Inflammation drives the development of depression and may affect neurotransmitters and thus neurocircuits increase the risk of depression. To investigate the influence of inhibition of inflammatory pathways on the biogenic amine neurotransmitters metabolism in depressive rats, sertraline, and meloxicam, the inhibitors of arachidonic acid - cyclooxygenase-2/lipoxygenase (AA-COX-2/5-LO) pathways, were given to depressive rats. After the development of depression model by chronic unpredictable mild stress (CUMS) for 6 weeks, Successful modeling rats were selected and randomly divided into CUMS group and medication administration group. After given medicine, The biogenic amine neurotransmitters in rat cortex and hippocampus were measured by high-performance liquid chromatography equipped with an electrochemical detector (HPLC-ECD). Compared with the normal group, the concentration of norepinephrine (NE) significantly decreased and the concentrations of Tyrosine (Tyr), Tryptophan (Trp), 3,4-dihydroxyphenyl acetic acid (DOPAC), 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) significantly increased in the CUMS group. Sertraline significantly inhibited the elevation of 5-HIAA. Meloxicam inhibited the decrease of NE level in CUMS-induced rat and the increase of Trp, MHPG, and 5-HIAA level in a dose-dependent manner. Caffeic acid inhibited the decrease of NE and the increase of Trp and MHPG in a dose-dependent manner. The inhibition of AA-COX-2/5-LO pathways can improve the behaviors of depression rats and suppress CUMS-induced changes in biogenic amines. Compared with the single-dose lipoxygenase (5-LO) or Cyclooxygenase-2 (COX-2) inhibitor, the combination treatment with meloxicam 1 mg/kg and caffeic acid 10 mg/kg have no significant improvement in CUMS-induced depression behavior and the level of cortical monoamine neurotransmitters and their metabolites.
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Affiliation(s)
- Dan Huang
- School of Pharmacy, Chongqing Medical University, Chongqing, 400016, China
| | - Lu Zhang
- West China-Washington Mitochondria and Metabolism Center, West China Hospital/West China Medical School, Sichuan University, Chengdu 610041, China
| | - Jun-Qing Yang
- School of Pharmacy, Chongqing Medical University, Chongqing, 400016, China
| | - Ying Luo
- School of Pharmacy, Chongqing Medical University, Chongqing, 400016, China
| | - Ting Cui
- Zunyi Medical and Pharmaceutical College, Zunyi, 563006, China
| | - Ting-Ting Du
- School of Pharmacy, Chongqing Medical University, Chongqing, 400016, China
| | - Xin-Hui Jiang
- School of Pharmacy, Chongqing Medical University, Chongqing, 400016, China
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11
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Subedi BP, Fitzpatrick PF. Mutagenesis of an Active-Site Loop in Tryptophan Hydroxylase Dramatically Slows the Formation of an Early Intermediate in Catalysis. J Am Chem Soc 2018; 140:5185-5192. [PMID: 29589922 DOI: 10.1021/jacs.8b00936] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Solution studies of the aromatic amino acid hydroxylases are consistent with the FeIVO intermediate not forming until both the amino acid and tetrahydropterin substrates have bound. Structural studies have shown that the positions of active-site loops differs significantly between the free enzyme and the enzyme-amino acid-tetrahydropterin complex. In tryptophan hydroxylase (TrpH) these mobile loops contain residues 124-134 and 365-371, with a key interaction involving Ile366. The I366N mutation in TrpH results in decreases of 1-2 orders of magnitude in the kcat and kcat/ Km values. Single turnover analyses establish that the limiting rate constant for turnover is product release for the wild-type enzyme but is formation of the first detectable intermediate I in catalysis in the mutant enzyme. The mutation does not alter the kinetics of NO binding to the ternary complex nor does it uncouple FeIVO formation from amino acid hydroxylation. The effects on the kcat value of wild-type TrpH of changing viscosity are consistent with rate-limiting product release. While the effect of viscosity on the kcat/ KO2 value is small, consistent with reversible oxygen binding, the effects on the kcat/ Km values for tryptophan and the tetrahydropterin are large, with the latter value exceeding the expected limit and varying with the identity of the viscogen. In contrast, the kinetic parameters of I366N TrpH show small changes with viscosity. The results are consistent with binding of the amino acid and pterin substrate to form the ternary complex being directly coupled to closure of loops over the active site and formation of the reactive complex. The mutation destabilizes this initial event.
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Affiliation(s)
- Bishnu P Subedi
- Department of Biochemistry and Structural Biology , University of Texas Health Science Center at San Antonio , San Antonio , Texas 78229 , United States
| | - Paul F Fitzpatrick
- Department of Biochemistry and Structural Biology , University of Texas Health Science Center at San Antonio , San Antonio , Texas 78229 , United States
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12
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Kal S, Que L. Dioxygen activation by nonheme iron enzymes with the 2-His-1-carboxylate facial triad that generate high-valent oxoiron oxidants. J Biol Inorg Chem 2017; 22:339-365. [PMID: 28074299 DOI: 10.1007/s00775-016-1431-2] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/13/2016] [Indexed: 11/24/2022]
Abstract
The 2-His-1-carboxylate facial triad is a widely used scaffold to bind the iron center in mononuclear nonheme iron enzymes for activating dioxygen in a variety of oxidative transformations of metabolic significance. Since the 1990s, over a hundred different iron enzymes have been identified to use this platform. This structural motif consists of two histidines and the side chain carboxylate of an aspartate or a glutamate arranged in a facial array that binds iron(II) at the active site. This triad occupies one face of an iron-centered octahedron and makes the opposite face available for the coordination of O2 and, in many cases, substrate, allowing the tailoring of the iron-dioxygen chemistry to carry out a plethora of diverse reactions. Activated dioxygen-derived species involved in the enzyme mechanisms include iron(III)-superoxo, iron(III)-peroxo, and high-valent iron(IV)-oxo intermediates. In this article, we highlight the major crystallographic, spectroscopic, and mechanistic advances of the past 20 years that have significantly enhanced our understanding of the mechanisms of O2 activation and the key roles played by iron-based oxidants.
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Affiliation(s)
- Subhasree Kal
- Department of Chemistry, Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Lawrence Que
- Department of Chemistry, Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA.
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13
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Subedi BP, Fitzpatrick PF. Kinetic Mechanism and Intrinsic Rate Constants for the Reaction of a Bacterial Phenylalanine Hydroxylase. Biochemistry 2016; 55:6848-6857. [DOI: 10.1021/acs.biochem.6b01012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bishnu P. Subedi
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio Texas 78229, United States
| | - Paul F. Fitzpatrick
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio Texas 78229, United States
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14
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Proshlyakov DA, McCracken J, Hausinger RP. Spectroscopic analyses of 2-oxoglutarate-dependent oxygenases: TauD as a case study. J Biol Inorg Chem 2016; 22:367-379. [PMID: 27812832 DOI: 10.1007/s00775-016-1406-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/25/2016] [Indexed: 11/28/2022]
Abstract
A wide range of spectroscopic approaches have been used to interrogate the mononuclear iron metallocenter in 2-oxoglutarate (2OG)-dependent oxygenases. The results from these spectroscopic studies have provided valuable insights into the structural changes at the active site during substrate binding and catalysis, thus providing critical information that complements investigations of these enzymes by X-ray crystallography, biochemical, and computational approaches. This mini-review highlights taurine hydroxylase (taurine:2OG dioxygenase, TauD) as a case study to illustrate the wealth of knowledge that can be generated by applying a diverse array of spectroscopic investigations to a single enzyme. In particular, electronic absorption, circular dichroism, magnetic circular dichroism, conventional and pulse electron paramagnetic, Mössbauer, X-ray absorption, and resonance Raman methods have been exploited to uncover the properties of the metal site in TauD.
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Affiliation(s)
- Denis A Proshlyakov
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - John McCracken
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Robert P Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA. .,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.
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15
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Abstract
Aromatic amino acid hydroxylases are members of a larger group of enzymes that use a mononuclear nonheme Fe center to catalyze a variety of thermodynamically challenging reactions in which O2 is used in the oxidative transformation of substrates. The hydroxylase enzymes are catalytically active in the ferrous oxidation state and are high-spin. To render the catalytic site EPR-active, we have used nitric oxide (NO) as a surrogate for substrate O2 to form an S=3/2 paramagnetic center. While the continuous-wave (cw)-EPR spectra of NO-enzyme adducts are rather generic, they provide electron spin echo envelope modulation (ESEEM) data that are rich with structural information derived from ligand hyperfine couplings. This chapter will focus on (2)H-ESEEM spectroscopy, an approach that we have taken for assigning these spectra and harvesting the unique information on Fe(II) coordination chemistry that they provide. While these spectroscopic measurements are routine, an emphasis will be placed on the analysis of cw-EPR and (2)H-ESEEM data using an unconstrained nonlinear optimization approach. These analysis methods are based on simple custom "scripts" that run in the MATLAB environment and that use EasySpin, a public-domain EPR simulation package, as their calculation engine. The examples provided here use a strategy that can be adapted for the treatment of most EPR measurements.
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16
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McCracken J, Cappillino PJ, McNally JS, Krzyaniak MD, Howart M, Tarves PC, Caradonna JP. Characterization of Water Coordination to Ferrous Nitrosyl Complexes with fac-N2O, cis-N2O2, and N2O3 Donor Ligands. Inorg Chem 2015; 54:6486-97. [DOI: 10.1021/acs.inorgchem.5b00788] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- John McCracken
- Department of Chemistry, Michigan State University, East
Lansing, Michigan 48824, United States
| | - Patrick J. Cappillino
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
- Department of Chemistry and Biochemistry, University of Massachusetts at Dartmouth, North Dartmouth, Massachusetts 02347, United States
| | - Joshua S. McNally
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Matthew D. Krzyaniak
- Department of Chemistry, Michigan State University, East
Lansing, Michigan 48824, United States
| | - Michael Howart
- Department of Chemistry, Michigan State University, East
Lansing, Michigan 48824, United States
| | - Paul C. Tarves
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - John P. Caradonna
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
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17
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McCracken J, Eser BE, Mannikko D, Krzyaniak MD, Fitzpatrick PF. HYSCORE Analysis of the Effects of Substrates on Coordination of Water to the Active Site Iron in Tyrosine Hydroxylase. Biochemistry 2015; 54:3759-71. [DOI: 10.1021/acs.biochem.5b00363] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- John McCracken
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Bekir E. Eser
- Department
of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, United States
| | - Donald Mannikko
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Matthew D. Krzyaniak
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Paul F. Fitzpatrick
- Department
of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, United States
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18
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Roberts KM, Khan CA, Hinck CS, Fitzpatrick PF. Activation of phenylalanine hydroxylase by phenylalanine does not require binding in the active site. Biochemistry 2014; 53:7846-53. [PMID: 25453233 PMCID: PMC4270383 DOI: 10.1021/bi501183x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
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Phenylalanine
hydroxylase (PheH), a liver enzyme that catalyzes
the hydroxylation of excess phenylalanine in the diet to tyrosine,
is activated by phenylalanine. The lack of activity at low levels
of phenylalanine has been attributed to the N-terminus of the protein’s
regulatory domain acting as an inhibitory peptide by blocking substrate
access to the active site. The location of the site at which phenylalanine
binds to activate the enzyme is unknown, and both the active site
in the catalytic domain and a separate site in the N-terminal regulatory
domain have been proposed. Binding of catecholamines to the active-site
iron was used to probe the accessibility of the active site. Removal
of the regulatory domain increases the rate constants for association
of several catecholamines with the wild-type enzyme by ∼2-fold.
Binding of phenylalanine in the active site is effectively abolished
by mutating the active-site residue Arg270 to lysine. The kcat/Kphe value is
down 104 for the mutant enzyme, and the Km value for phenylalanine for the mutant enzyme is >0.5
M. Incubation of the R270K enzyme with phenylalanine also results
in a 2-fold increase in the rate constants for catecholamine binding.
The change in the tryptophan fluorescence emission spectrum seen in
the wild-type enzyme upon activation by phenylalanine is also seen
with the R270K mutant enzyme in the presence of phenylalanine. Both
results establish that activation of PheH by phenylalanine does not
require binding of the amino acid in the active site. This is consistent
with a separate allosteric site, likely in the regulatory domain.
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Affiliation(s)
- Kenneth M Roberts
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78229, United States
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19
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Roberts KM, Tormos JR, Fitzpatrick PF. Characterization of unstable products of flavin- and pterin-dependent enzymes by continuous-flow mass spectrometry. Biochemistry 2014; 53:2672-9. [PMID: 24713088 PMCID: PMC4010283 DOI: 10.1021/bi500267c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
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Continuous-flow mass spectrometry
(CFMS) was used to monitor the
products formed during the initial 0.25–20 s of the reactions
catalyzed by the flavoprotein N-acetylpolyamine oxidase
(PAO) and the pterin-dependent enzymes phenylalanine hydroxylase (PheH)
and tyrosine hydroxylase (TyrH). N,N′-Dibenzyl-1,4-diaminobutane (DBDB) is a substrate for PAO
for which amine oxidation is rate-limiting. CFMS of the reaction showed
formation of an initial imine due to oxidation of an exo-carbon–nitrogen bond. Nonenzymatic hydrolysis of the imine
formed benzaldehyde and N-benzyl-1,4-diaminobutane;
the subsequent oxidation by PAO of the latter to an additional imine
could also be followed. Measurement of the deuterium kinetic isotope
effect on DBDB oxidation by CFMS yielded a value of 7.6 ± 0.3,
in good agreement with a value of 6.7 ± 0.6 from steady-state
kinetic analyses. In the PheH reaction, the transient formation of
the 4a-hydroxypterin product was readily detected; tandem mass spectrometry
confirmed attachment of the oxygen to C(4a). With wild-type TyrH,
the 4a-hydroxypterin was also the product. In contrast, no product
other than a dihydropterin could be detected in the reaction of the
mutant protein E332A TyrH.
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Affiliation(s)
- Kenneth M Roberts
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78229, United States
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