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McCullagh M, Zeczycki TN, Kariyawasam CS, Durie CL, Halkidis K, Fitzkee NC, Holt JM, Fenton AW. What is allosteric regulation? Exploring the exceptions that prove the rule! J Biol Chem 2024; 300:105672. [PMID: 38272229 PMCID: PMC10897898 DOI: 10.1016/j.jbc.2024.105672] [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: 06/21/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 01/27/2024] Open
Abstract
"Allosteric" was first introduced to mean the other site (i.e., a site distinct from the active or orthosteric site), an adjective for "regulation" to imply a regulatory outcome resulting from ligand binding at another site. That original idea outlines a system with two ligand-binding events at two distinct locations on a macromolecule (originally a protein system), which defines a four-state energy cycle. An allosteric energy cycle provides a quantifiable allosteric coupling constant and focuses our attention on the unique properties of the four equilibrated protein complexes that constitute the energy cycle. Because many observed phenomena have been referenced as "allosteric regulation" in the literature, the goal of this work is to use literature examples to explore which systems are and are not consistent with the two-ligand thermodynamic energy cycle-based definition of allosteric regulation. We emphasize the need for consistent language so comparisons can be made among the ever-increasing number of allosteric systems. Building on the mutually exclusive natures of an energy cycle definition of allosteric regulation versus classic two-state models, we conclude our discussion by outlining how the often-proposed Rube-Goldberg-like mechanisms are likely inconsistent with an energy cycle definition of allosteric regulation.
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Affiliation(s)
- Martin McCullagh
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Tonya N Zeczycki
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University, Greenville, North Carolina, USA
| | - Chathuri S Kariyawasam
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, USA
| | - Clarissa L Durie
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Konstantine Halkidis
- Department of Hematologic Malignancies and Cellular Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas, USA; Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Nicholas C Fitzkee
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, USA
| | - Jo M Holt
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Aron W Fenton
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas, USA.
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2
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Vedel IM, Prestel A, Zhang Z, Skawinska NT, Stark H, Harris P, Kragelund BB, Peters GHJ. Structural characterization of human tryptophan hydroxylase 2 reveals that L-Phe is superior to L-Trp as the regulatory domain ligand. Structure 2023:S0969-2126(23)00127-2. [PMID: 37119821 DOI: 10.1016/j.str.2023.04.004] [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: 12/17/2022] [Revised: 03/03/2023] [Accepted: 04/04/2023] [Indexed: 05/01/2023]
Abstract
Tryptophan hydroxylase 2 (TPH2) catalyzes the rate-limiting step in serotonin biosynthesis in the brain. Consequently, regulation of TPH2 is relevant for serotonin-related diseases, yet the regulatory mechanism of TPH2 is poorly understood and structural and dynamical insights are missing. We use NMR spectroscopy to determine the structure of a 47 N-terminally truncated variant of the regulatory domain (RD) dimer of human TPH2 in complex with L-Phe, and show that L-Phe is the superior RD ligand compared with the natural substrate, L-Trp. Using cryo-EM, we obtain a low-resolution structure of a similarly truncated variant of the complete tetrameric enzyme with dimerized RDs. The cryo-EM two-dimensional (2D) class averages additionally indicate that the RDs are dynamic in the tetramer and likely exist in a monomer-dimer equilibrium. Our results provide structural information on the RD as an isolated domain and in the TPH2 tetramer, which will facilitate future elucidation of TPH2's regulatory mechanism.
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Affiliation(s)
- Ida M Vedel
- Department of Chemistry, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
| | - Andreas Prestel
- Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark
| | - Zhenwei Zhang
- Department of Structural Dynamics, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Natalia T Skawinska
- Department of Chemistry, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
| | - Holger Stark
- Department of Structural Dynamics, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, 37077 Göttingen, Germany
| | - Pernille Harris
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Birthe B Kragelund
- Department of Biology, University of Copenhagen, Ole Maaløes vej 5, 2200 Copenhagen N, Denmark.
| | - Günther H J Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark.
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3
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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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4
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Bueno-Carrasco MT, Cuéllar J, Flydal MI, Santiago C, Kråkenes TA, Kleppe R, López-Blanco JR, Marcilla M, Teigen K, Alvira S, Chacón P, Martinez A, Valpuesta JM. Structural mechanism for tyrosine hydroxylase inhibition by dopamine and reactivation by Ser40 phosphorylation. Nat Commun 2022; 13:74. [PMID: 35013193 PMCID: PMC8748767 DOI: 10.1038/s41467-021-27657-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 12/03/2021] [Indexed: 12/15/2022] Open
Abstract
Tyrosine hydroxylase (TH) catalyzes the rate-limiting step in the biosynthesis of dopamine (DA) and other catecholamines, and its dysfunction leads to DA deficiency and parkinsonisms. Inhibition by catecholamines and reactivation by S40 phosphorylation are key regulatory mechanisms of TH activity and conformational stability. We used Cryo-EM to determine the structures of full-length human TH without and with DA, and the structure of S40 phosphorylated TH, complemented with biophysical and biochemical characterizations and molecular dynamics simulations. TH presents a tetrameric structure with dimerized regulatory domains that are separated 15 Å from the catalytic domains. Upon DA binding, a 20-residue α-helix in the flexible N-terminal tail of the regulatory domain is fixed in the active site, blocking it, while S40-phosphorylation forces its egress. The structures reveal the molecular basis of the inhibitory and stabilizing effects of DA and its counteraction by S40-phosphorylation, key regulatory mechanisms for homeostasis of DA and TH. Tyrosine hydroxylase (TH) catalyzes the rate-limiting step in the synthesis of the catecholamine neurotransmitters and hormones dopamine (DA), adrenaline and noradrenaline. Here, the authors present the cryo-EM structures of full-length human TH in the apo form and bound with DA, as well as the structure of Ser40 phosphorylated TH, and discuss the inhibitory and stabilizing effects of DA on TH and its counteraction by Ser40-phosphorylation.
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Affiliation(s)
| | - Jorge Cuéllar
- Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.
| | - Marte I Flydal
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - César Santiago
- Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | | | - Rune Kleppe
- Norwegian Centre for Maritime and Diving Medicine, Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway
| | | | | | - Knut Teigen
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Sara Alvira
- Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.,School of Biochemistry, University of Bristol, Bristol, BS8 1TD, UK
| | - Pablo Chacón
- Instituto de Química Física Rocasolano (IQFR-CSIC), Madrid, Spain
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, Bergen, Norway.
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5
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Inukai S, Hara S, Ichinose H. Tyrosine hydroxylase activity is regulated through the modification of the 176th cysteine residue. Biochem Biophys Res Commun 2021; 589:209-214. [PMID: 34922205 DOI: 10.1016/j.bbrc.2021.12.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 12/07/2021] [Indexed: 11/16/2022]
Abstract
Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the biosynthesis of dopamine (DA), and the regulation of its activity is important for DA homeostasis. In this study, we focused on the modification of TH through a cysteine residue. We found that incubation with N-ethylmaleimide (NEM), a cysteine modification reagent, inactivated TH. The responsible cysteine was identified as Cys176 of human TH with recombinant mutant proteins. We further examined how NEM modification was affected by the states of TH. DA binding, a feedback inhibition mechanism of TH, delayed the modification and inactivation of TH by NEM. In contrast, the S40E mutant, which mimics the phosphorylation of Ser40 that suppresses DA binding and is thus considered as an active state of TH, did not affect modification and inactivation. These results suggest that the modification of Cys176 can inhibit even phosphorylated active TH. In addition, we found that DA oxides, which are generated by oxidative stress in dopaminergic neurons, reacted with TH through Cys176 and inhibited its activity, similar to NEM. These results suggest that the modification of Cys176 of TH could be involved in the mechanisms of neurotoxicity caused by DA oxides.
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Affiliation(s)
- Shunya Inukai
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Satoshi Hara
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroshi Ichinose
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.
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6
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Lopes RR, Tomé CS, Russo R, Paterna R, Leandro J, Candeias NR, Gonçalves LMD, Teixeira M, Sousa PMF, Guedes RC, Vicente JB, Gois PMP, Leandro P. Modulation of Human Phenylalanine Hydroxylase by 3-Hydroxyquinolin-2(1H)-One Derivatives. Biomolecules 2021; 11:biom11030462. [PMID: 33808760 PMCID: PMC8003416 DOI: 10.3390/biom11030462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/08/2021] [Accepted: 03/13/2021] [Indexed: 01/14/2023] Open
Abstract
Phenylketonuria (PKU) is a genetic disease caused by deficient activity of human phenylalanine hydroxylase (hPAH) that, when untreated, can lead to severe psychomotor impairment. Protein misfolding is recognized as the main underlying pathogenic mechanism of PKU. Therefore, the use of stabilizers of protein structure and/or activity is an attractive therapeutic strategy for this condition. Here, we report that 3-hydroxyquinolin-2(1H)-one derivatives can act as protectors of hPAH enzyme activity. Electron paramagnetic resonance spectroscopy demonstrated that the 3-hydroxyquinolin-2(1H)-one compounds affect the coordination of the non-heme ferric center at the enzyme active-site. Moreover, surface plasmon resonance studies showed that these stabilizing compounds can be outcompeted by the natural substrate l-phenylalanine. Two of the designed compounds functionally stabilized hPAH by maintaining protein activity. This effect was observed on the recombinant purified protein and in a cellular model. Besides interacting with the catalytic iron, one of the compounds also binds to the N-terminal regulatory domain, although to a different location from the allosteric l-Phe binding site, as supported by the solution structures obtained by small-angle X-ray scattering.
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Affiliation(s)
- Raquel R. Lopes
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
| | - Catarina S. Tomé
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal;
- Instituto de Biologia Experimental e Tecnológica, Quinta do Marquês, 2780-155 Oeiras, Portugal;
| | - Roberto Russo
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
| | - Roberta Paterna
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
| | - João Leandro
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
| | - Nuno R. Candeias
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33101 Tampere, Finland;
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Lídia M. D. Gonçalves
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
| | - Miguel Teixeira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal;
| | - Pedro M. F. Sousa
- Instituto de Biologia Experimental e Tecnológica, Quinta do Marquês, 2780-155 Oeiras, Portugal;
| | - Rita C. Guedes
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
| | - João B. Vicente
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal;
- Correspondence: (J.B.V.); (P.M.P.G.); (P.L.); Tel.: +351-217946400 (P.L.)
| | - Pedro M. P. Gois
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
- Correspondence: (J.B.V.); (P.M.P.G.); (P.L.); Tel.: +351-217946400 (P.L.)
| | - Paula Leandro
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (R.R.L.); (C.S.T.); (R.R.); (R.P.); (J.L.); (L.M.D.G.); (R.C.G.)
- Correspondence: (J.B.V.); (P.M.P.G.); (P.L.); Tel.: +351-217946400 (P.L.)
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7
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Ghorbani S, Szigetvari PD, Haavik J, Kleppe R. Serine 19 phosphorylation and 14‐3‐3 binding regulate phosphorylation and dephosphorylation of tyrosine hydroxylase on serine 31 and serine 40. J Neurochem 2019; 152:29-47. [DOI: 10.1111/jnc.14872] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/27/2019] [Accepted: 08/29/2019] [Indexed: 01/09/2023]
Affiliation(s)
- Sadaf Ghorbani
- Department of Biomedicine K.G. Jebsen Centre for Research on Neuropsychiatric Disorders University of Bergen Bergen Norway
| | - Peter D. Szigetvari
- Department of Biomedicine K.G. Jebsen Centre for Research on Neuropsychiatric Disorders University of Bergen Bergen Norway
| | - Jan Haavik
- Department of Biomedicine K.G. Jebsen Centre for Research on Neuropsychiatric Disorders University of Bergen Bergen Norway
- Division of Psychiatry Haukeland University Hospital Bergen Norway
| | - Rune Kleppe
- Division of Psychiatry Haukeland University Hospital Bergen Norway
- Computational Biology Unit Department of Informatics University of Bergen Bergen Norway
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8
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Baumann A, Jorge-Finnigan A, Jung-Kc K, Sauter A, Horvath I, Morozova-Roche LA, Martinez A. Tyrosine Hydroxylase Binding to Phospholipid Membranes Prompts Its Amyloid Aggregation and Compromises Bilayer Integrity. Sci Rep 2016; 6:39488. [PMID: 28004763 PMCID: PMC5177901 DOI: 10.1038/srep39488] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 11/21/2016] [Indexed: 12/14/2022] Open
Abstract
Tyrosine hydroxylase (TH), a rate-limiting enzyme in the synthesis of catecholamine neurotransmitters and hormones, binds to negatively charged phospholipid membranes. Binding to both large and giant unilamellar vesicles causes membrane permeabilization, as observed by efflux and influx of fluorescence dyes. Whereas the initial protein-membrane interaction involves the N-terminal tail that constitutes an extension of the regulatory ACT-domain, prolonged membrane binding induces misfolding and self-oligomerization of TH over time as shown by circular dichroism and Thioflavin T fluorescence. The gradual amyloid-like aggregation likely occurs through cross-β interactions involving aggregation-prone motives in the catalytic domains, consistent with the formation of chain and ring-like protofilaments observed by atomic force microscopy in monolayer-bound TH. PC12 cells treated with the neurotoxin 6-hydroxydopamine displayed increased TH levels in the mitochondrial fraction, while incubation of isolated mitochondria with TH led to a decrease in the mitochondrial membrane potential. Furthermore, cell-substrate impedance and viability assays showed that supplementing the culture media with TH compromises cell viability over time. Our results revealed that the disruptive effect of TH on cell membranes may be a cytotoxic and pathogenic factor if the regulation and intracellular stability of TH is compromised.
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Affiliation(s)
- Anne Baumann
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway.,Division of Psychiatry, Haukeland University Hospital, 5021 Bergen, Norway
| | - Ana Jorge-Finnigan
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway.,K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
| | - Kunwar Jung-Kc
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway
| | - Alexander Sauter
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway.,Department of Clinical Dentistry, University of Bergen, 5009 Bergen, Norway
| | - Istvan Horvath
- Department of Medical Biochemistry and Biophysics, Umeå University, 90187 Umeå, Sweden
| | | | - Aurora Martinez
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway.,K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
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9
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Stable preparations of tyrosine hydroxylase provide the solution structure of the full-length enzyme. Sci Rep 2016; 6:30390. [PMID: 27462005 PMCID: PMC4961952 DOI: 10.1038/srep30390] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/30/2016] [Indexed: 01/22/2023] Open
Abstract
Tyrosine hydroxylase (TH) catalyzes the rate-limiting step in the biosynthesis of catecholamine neurotransmitters. TH is a highly complex enzyme at mechanistic, structural, and regulatory levels, and the preparation of kinetically and conformationally stable enzyme for structural characterization has been challenging. Here, we report on improved protocols for purification of recombinant human TH isoform 1 (TH1), which provide large amounts of pure, stable, active TH1 with an intact N-terminus. TH1 purified through fusion with a His-tagged maltose-binding protein on amylose resin was representative of the iron-bound functional enzyme, showing high activity and stabilization by the natural feedback inhibitor dopamine. TH1 purified through fusion with a His-tagged ZZ domain on TALON is remarkably stable, as it was partially inhibited by resin-derived cobalt. This more stable enzyme preparation provided high-quality small-angle X-ray scattering (SAXS) data and reliable structural models of full-length tetrameric TH1. The SAXS-derived model reveals an elongated conformation (Dmax = 20 nm) for TH1, different arrangement of the catalytic domains compared with the crystal structure of truncated forms, and an N-terminal region with an unstructured tail that hosts the phosphorylation sites and a separated Ala-rich helical motif that may have a role in regulation of TH by interacting with binding partners.
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10
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The regulatory domain of human tryptophan hydroxylase 1 forms a stable dimer. Biochem Biophys Res Commun 2016; 476:457-461. [PMID: 27255998 DOI: 10.1016/j.bbrc.2016.05.144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 05/27/2016] [Indexed: 02/06/2023]
Abstract
The three eukaryotic aromatic amino acid hydroxylases phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase have essentially identical catalytic domains and discrete regulatory domains. The regulatory domains of phenylalanine hydroxylase form ACT domain dimers when phenylalanine is bound to an allosteric site. In contrast the regulatory domains of tyrosine hydroxylase form a stable ACT dimer that does not bind the amino acid substrate. The regulatory domain of isoform 1 of human tryptophan hydroxylase was expressed and purified; mutagenesis of Cys64 was required to prevent formation of disulfide-linked dimers. The resulting protein behaved as a dimer upon gel filtration and in analytical ultracentrifugation. The sw value of the protein was unchanged from 2.7 to 35 μM, a concentration range over which the regulatory domain of phenylalanine hydroxylase forms both monomers and dimers, consistent with the regulatory domain of tryptophan hydroxylase 1 forming a stable dimer stable that does not undergo a monomer-dimer equilibrium. Addition of phenylalanine, a good substrate for the enzyme, had no effect on the sw value, consistent with there being no allosteric site for the amino acid substrate.
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11
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Discovery of compounds that protect tyrosine hydroxylase activity through different mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1078-89. [DOI: 10.1016/j.bbapap.2015.04.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/21/2015] [Accepted: 04/24/2015] [Indexed: 12/12/2022]
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12
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Fitzpatrick PF. Structural insights into the regulation of aromatic amino acid hydroxylation. Curr Opin Struct Biol 2015; 35:1-6. [PMID: 26241318 DOI: 10.1016/j.sbi.2015.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/30/2015] [Accepted: 07/15/2015] [Indexed: 11/30/2022]
Abstract
The aromatic amino acid hydroxylases phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase are homotetramers, with each subunit containing a homologous catalytic domain and a divergent regulatory domain. The solution structure of the regulatory domain of tyrosine hydroxylase establishes that it contains a core ACT domain similar to that in phenylalanine hydroxylase. The isolated regulatory domain of tyrosine hydroxylase forms a stable dimer, while that of phenylalanine hydroxylase undergoes a monomer-dimer equilibrium, with phenylalanine stabilizing the dimer. These solution properties are consistent with the regulatory mechanisms of the two enzymes, in that phenylalanine hydroxylase is activated by phenylalanine binding to an allosteric site, while tyrosine hydroxylase is regulated by binding of catecholamines in the active site.
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Affiliation(s)
- Paul F Fitzpatrick
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, United States.
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13
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Zhang S, Huang T, Ilangovan U, Hinck AP, Fitzpatrick PF. The solution structure of the regulatory domain of tyrosine hydroxylase. J Mol Biol 2013; 426:1483-97. [PMID: 24361276 DOI: 10.1016/j.jmb.2013.12.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/13/2013] [Accepted: 12/10/2013] [Indexed: 11/19/2022]
Abstract
Tyrosine hydroxylase (TyrH) catalyzes the hydroxylation of tyrosine to form 3,4-dihydroxyphenylalanine in the biosynthesis of the catecholamine neurotransmitters. The activity of the enzyme is regulated by phosphorylation of serine residues in a regulatory domain and by binding of catecholamines to the active site. Available structures of TyrH lack the regulatory domain, limiting the understanding of the effect of regulation on structure. We report the use of NMR spectroscopy to analyze the solution structure of the isolated regulatory domain of rat TyrH. The protein is composed of a largely unstructured N-terminal region (residues 1-71) and a well-folded C-terminal portion (residues 72-159). The structure of a truncated version of the regulatory domain containing residues 65-159 has been determined and establishes that it is an ACT domain. The isolated domain is a homodimer in solution, with the structure of each monomer very similar to that of the core of the regulatory domain of phenylalanine hydroxylase. Two TyrH regulatory domain monomers form an ACT domain dimer composed of a sheet of eight strands with four α-helices on one side of the sheet. Backbone dynamic analyses were carried out to characterize the conformational flexibility of TyrH65-159. The results provide molecular details critical for understanding the regulatory mechanism of TyrH.
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Affiliation(s)
- Shengnan Zhang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Tao Huang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Udayar Ilangovan
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Andrew P Hinck
- 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.
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14
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Briggs GD, Bulley J, Dickson PW. Catalytic domain surface residues mediating catecholamine inhibition in tyrosine hydroxylase. J Biochem 2013; 155:183-93. [DOI: 10.1093/jb/mvt110] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Skjevik AA, Mileni M, Baumann A, Halskau O, Teigen K, Stevens RC, Martinez A. The N-terminal sequence of tyrosine hydroxylase is a conformationally versatile motif that binds 14-3-3 proteins and membranes. J Mol Biol 2013; 426:150-68. [PMID: 24055376 DOI: 10.1016/j.jmb.2013.09.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/27/2013] [Accepted: 09/11/2013] [Indexed: 01/17/2023]
Abstract
Tyrosine hydroxylase (TH) catalyzes the rate-limiting step in the synthesis of catecholamine neurotransmitters, and a reduction in TH activity is associated with several neurological diseases. Human TH is regulated, among other mechanisms, by Ser19-phosphorylation-dependent interaction with 14-3-3 proteins. The N-terminal sequence (residues 1-43), which corresponds to an extension to the TH regulatory domain, also interacts with negatively charged membranes. By using X-ray crystallography together with molecular dynamics simulations and structural bioinformatics analysis, we have probed the conformations of the Ser19-phosphorylated N-terminal peptide [THp-(1-43)] bound to 14-3-3γ, free in solution and bound to a phospholipid bilayer, and of the unphosphorylated peptide TH-(1-43) both free and bilayer bound. As seen in the crystal structure of THp-(1-43) complexed with 14-3-3γ, the region surrounding pSer19 adopts an extended conformation in the bound state, whereas THp-(1-43) adopts a bent conformation when free in solution, with higher content of secondary structure and higher number of internal hydrogen bonds. TH-(1-43) in solution presents the highest mobility and least defined structure of all forms studied, and it shows an energetically more favorable interaction with membranes relative to THp-(1-43). Cationic residues, notably Arg15 and Arg16, which are the recognition sites of the kinases phosphorylating at Ser19, are also contributing to the interaction with the membrane. Our results reveal the structural flexibility of this region of TH, in accordance with the functional versatility and conformational adaptation to different partners. Furthermore, this structural information has potential relevance for the development of therapeutics for neurodegenerative disorders, through modulation of TH-partner interactions.
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Affiliation(s)
| | - Mauro Mileni
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Anne Baumann
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
| | - Oyvind Halskau
- Department of Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5020 Bergen, Norway
| | - Knut Teigen
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
| | - Raymond C Stevens
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway.
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16
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Daubner SC, Avila A, Bailey JO, Barrera D, Bermudez JY, Giles DH, Khan CA, Shaheen N, Thompson JW, Vasquez J, Oxley SP, Fitzpatrick PF. Mutagenesis of a specificity-determining residue in tyrosine hydroxylase establishes that the enzyme is a robust phenylalanine hydroxylase but a fragile tyrosine hydroxylase. Biochemistry 2013; 52:1446-55. [PMID: 23368961 PMCID: PMC3584195 DOI: 10.1021/bi400031n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The aromatic amino acid hydroxylases tyrosine hydroxylase (TyrH) and phenylalanine hydroxylase (PheH) have essentially identical active sites; however, PheH is nearly incapable of hydroxylating tyrosine, while TyrH can readily hydroxylate both tyrosine and phenylalanine. Previous studies have indicated that Asp425 of TyrH is important in determining the substrate specificity of that enzyme [Daubner, S. C., Melendez, J., and Fitzpatrick, P. F. (2000) Biochemistry 39, 9652-9661]. Alanine-scanning mutagenesis of amino acids 423-427, a mobile loop containing Asp425, shows that only mutagenesis of Asp425 alters the activity of the enzyme significantly. Saturation mutagenesis of Asp425 results in large (up to 10(4)) decreases in the V(max) and V(max)/K(tyr) values for tyrosine hydroxylation, but only small decreases or even increases in the V(max) and V(max)/K(phe) values for phenylalanine hydroxylation. The decrease in the tyrosine hydroxylation activity of the mutant proteins is due to an uncoupling of tetrahydropterin oxidation from amino acid hydroxylation with tyrosine as the amino acid substrate. In contrast, with the exception of the D425W mutant, the extent of coupling of tetrahydropterin oxidation and amino acid hydroxylation is unaffected or increases with phenylalanine as the amino acid substrate. The decrease in the V(max) value with tyrosine as the substrate shows a negative correlation with the hydrophobicity of the amino acid residue at position 425. The results are consistent with a critical role of Asp425 being to prevent a hydrophobic interaction that results in a restricted active site in which hydroxylation of tyrosine does not occur.
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Affiliation(s)
- S. Colette Daubner
- Department of Biological Sciences, St. Mary’s University, San Antonio TX 78228
| | - Audrey Avila
- Department of Biological Sciences, St. Mary’s University, San Antonio TX 78228
| | - Johnathan O. Bailey
- Department of Biochemistry and Biophysics, Texas A&M University, College Station TX 77840
| | - Dimitrios Barrera
- Department of Chemistry and Biochemistry, St. Mary’s University, San Antonio TX 78228
| | - Jaclyn Y. Bermudez
- Department of Biological Sciences, St. Mary’s University, San Antonio TX 78228
| | - David H. Giles
- Department of Biochemistry, University of Texas Health Science Center San Antonio, San Antonio TX 78229
| | - Crystal A. Khan
- Department of Biochemistry, University of Texas Health Science Center San Antonio, San Antonio TX 78229
| | - Noel Shaheen
- Department of Biological Sciences, St. Mary’s University, San Antonio TX 78228
| | - Janie Womac Thompson
- Department of Biochemistry and Biophysics, Texas A&M University, College Station TX 77840
| | - Jessica Vasquez
- Department of Biochemistry and Biophysics, Texas A&M University, College Station TX 77840
| | - Susan P. Oxley
- Department of Chemistry and Biochemistry, St. Mary’s University, San Antonio TX 78228
| | - Paul F. Fitzpatrick
- Department of Biochemistry, University of Texas Health Science Center San Antonio, San Antonio TX 78229
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17
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Fitzpatrick PF. Allosteric regulation of phenylalanine hydroxylase. Arch Biochem Biophys 2012; 519:194-201. [PMID: 22005392 PMCID: PMC3271142 DOI: 10.1016/j.abb.2011.09.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 09/27/2011] [Accepted: 09/28/2011] [Indexed: 10/16/2022]
Abstract
The liver enzyme phenylalanine hydroxylase is responsible for conversion of excess phenylalanine in the diet to tyrosine. Phenylalanine hydroxylase is activated by phenylalanine; this activation is inhibited by the physiological reducing substrate tetrahydrobiopterin. Phosphorylation of Ser16 lowers the concentration of phenylalanine for activation. This review discusses the present understanding of the molecular details of the allosteric regulation of the enzyme.
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Affiliation(s)
- Paul F Fitzpatrick
- Department of Biochemistry and Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, TX 78229-3900, USA.
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18
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Monitoring allostery in D2O: a necessary control in studies using hydrogen/deuterium exchange to characterize allosteric regulation. Anal Bioanal Chem 2011; 401:1083-6. [PMID: 21701851 DOI: 10.1007/s00216-011-5133-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 04/15/2011] [Accepted: 05/20/2011] [Indexed: 10/18/2022]
Abstract
There is currently a renewed focus aimed at understanding allosteric mechanisms at atomic resolution. This current interest seeks to understand how both changes in protein conformations and changes in protein dynamics contribute to relaying an allosteric signal between two ligand binding sites on a protein (e.g., active and allosteric sites). Both nuclear magnetic resonance (NMR), by monitoring protein dynamics directly, and hydrogen/deuterium exchange, by monitoring solvent accessibility of backbone amides, offer insights into protein dynamics. Unfortunately, many allosteric proteins exceed the size limitations of standard NMR techniques. Although hydrogen/deuterium exchange as detected by mass spectrometry (H/DX-MS) offers an alternative evaluation method, any application of hydrogen/deuterium exchange requires that the property being measured functions in both H(2)O and D(2)O. Due to the promising future H/DX-MS has in the evaluation of allosteric mechanisms in large proteins, we demonstrate an evaluation of allosteric regulation in D(2)O. Exemplified using phenylalanine inhibition of rabbit muscle pyruvate kinase, we find that binding of the inhibitor is greatly reduced in D(2)O, but the effector continues to elicit an allosteric response.
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19
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Wang S, Lasagna M, Daubner SC, Reinhart GD, Fitzpatrick PF. Fluorescence spectroscopy as a probe of the effect of phosphorylation at serine 40 of tyrosine hydroxylase on the conformation of its regulatory domain. Biochemistry 2011; 50:2364-70. [PMID: 21302933 DOI: 10.1021/bi101844p] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phosphorylation of Ser40 in the regulatory domain of tyrosine hydroxylase activates the enzyme by increasing the rate constant for dissociation of inhibitory catecholamines from the active site by 3 orders of magnitude. To probe the changes in the structure of the N-terminal domain upon phosphorylation, individual phenylalanine residues at positions 14, 34, and 74 were replaced with tryptophan in a form of the protein in which the endogenous tryptophans had all been mutated to phenylalanine (W(3)F TyrH). The steady-state fluorescence anisotropy of F74W W(3)F TyrH was unaffected by phosphorylation, but the anisotropies of both F14W and F34W W(3)F TyrH increased significantly upon phosphorylation. The fluorescence of the single tryptophan residue at position 74 was less readily quenched by acrylamide than those at the other two positions; fluorescence increased the rate constant for quenching of the residues at positions 14 and 34 but did not affect that for the residue at position 74. Frequency domain analyses were consistent with phosphorylation having no effect on the amplitude of the rotational motion of the indole ring at position 74, resulting in a small increase in the rotational motion of the residue at position 14 and resulting in a larger increase in the rotational motion of the residue at position 34. These results are consistent with the local environment at position 74 being unaffected by phosphorylation, that at position 34 becoming much more flexible upon phosphorylation, and that at position 14 becoming slightly more flexible upon phosphorylation. The results support a model in which phosphorylation at Ser40 at the N-terminus of the regulatory domain causes a conformational change to a more open conformation in which the N-terminus of the protein no longer inhibits dissociation of a bound catecholamine from the active site.
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Affiliation(s)
- Shanzhi Wang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, United States
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20
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Daubner SC, Le T, Wang S. Tyrosine hydroxylase and regulation of dopamine synthesis. Arch Biochem Biophys 2010; 508:1-12. [PMID: 21176768 DOI: 10.1016/j.abb.2010.12.017] [Citation(s) in RCA: 620] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 01/22/2023]
Abstract
Tyrosine hydroxylase is the rate-limiting enzyme of catecholamine biosynthesis; it uses tetrahydrobiopterin and molecular oxygen to convert tyrosine to DOPA. Its amino terminal 150 amino acids comprise a domain whose structure is involved in regulating the enzyme's activity. Modes of regulation include phosphorylation by multiple kinases at four different serine residues, and dephosphorylation by two phosphatases. The enzyme is inhibited in feedback fashion by the catecholamine neurotransmitters. Dopamine binds to TyrH competitively with tetrahydrobiopterin, and interacts with the R domain. TyrH activity is modulated by protein-protein interactions with enzymes in the same pathway or the tetrahydrobiopterin pathway, structural proteins considered to be chaperones that mediate the neuron's oxidative state, and the protein that transfers dopamine into secretory vesicles. TyrH is modified in the presence of NO, resulting in nitration of tyrosine residues and the glutathionylation of cysteine residues.
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Affiliation(s)
- S Colette Daubner
- Department of Biological Sciences, St. Mary's University, San Antonio, TX 78228, USA.
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21
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Li J, Dangott LJ, Fitzpatrick PF. Regulation of phenylalanine hydroxylase: conformational changes upon phenylalanine binding detected by hydrogen/deuterium exchange and mass spectrometry. Biochemistry 2010; 49:3327-35. [PMID: 20307070 DOI: 10.1021/bi1001294] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Phenylalanine acts as an allosteric activator of the tetrahydropterin-dependent enzyme phenylalanine hydroxylase. Hydrogen/deuterium exchange monitored by mass spectrometry has been used to gain insight into local conformational changes accompanying activation of rat phenylalanine hydroxylase by phenylalanine. Peptides in the regulatory and catalytic domains that lie in the interface between these two domains show large increases in the extent of deuterium incorporation from solvent in the presence of phenylalanine. In contrast, the effects of phenylalanine on the exchange kinetics of a mutant enzyme lacking the regulatory domain are limited to peptides surrounding the binding site for the amino acid substrate. These results support a model in which the N-terminus of the protein acts as an inhibitory peptide, with phenylalanine binding causing a conformational change in the regulatory domain that alters the interaction between the catalytic and regulatory domains.
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Affiliation(s)
- Jun Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station,Texas 77843-2128, USA
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22
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Eser BE, Fitzpatrick PF. Measurement of intrinsic rate constants in the tyrosine hydroxylase reaction. Biochemistry 2010; 49:645-52. [PMID: 20025246 DOI: 10.1021/bi901874e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tyrosine hydroxylase (TyrH) is a pterin-dependent mononuclear non-heme aromatic amino acid hydroxylase that catalyzes the conversion of tyrosine to dihydroxyphenylalanine (DOPA). Chemical quench analyses of the enzymatic reaction show a burst of DOPA formation, followed by a linear rate equal to the k(cat) value at both 5 and 30 degrees C. The effects of increasing solvent viscosity confirm that k(cat) is approximately 84% limited by diffusion, most probably due to slow product release, and that tyrosine has a commitment to catalysis of 0.45. The effect of viscosity on the k(cat)/K(m) for 6-methyltetrahydropterin is greater than the theoretical limit, consistent with the coupling of pterin binding to the movement of a surface loop. The absorbance changes in the spectrum of the tetrahydropterin during the first turnover, the kinetics of DOPA formation during the first turnover, and the previously described kinetics for formation and decay of the Fe(IV)O intermediate [Eser, B. E., Barr, E. W., Frantom, P. A., Saleh, L., Bollinger, J. M., Jr., Krebs, C., and Fitzpatrick, P. F. (2007) J. Am. Chem. Soc. 129, 11334-11335] were analyzed globally, yielding a single set of rate constants for the TyrH reaction. Reversible binding of oxygen is followed by formation of Fe(IV)O and 4a-hydroxypterin with a rate constant of 13 s(-1) at 5 degrees C. Transfer of oxygen from Fe(IV)O to tyrosine to form DOPA follows with a rate constant of 22 s(-1). Release of DOPA and/or the 4a-hydroxypterin with a rate constant of 0.86 s(-1) completes the turnover.
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Affiliation(s)
- Bekir E Eser
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
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