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Rovelli V, Cefalo G, Ercoli V, Zuvadelli J, Olivia T, Graziani D, Luisella A, Bassi D, Re Dionigi A, Selmi R, Paci S, Salvatici E, Banderali G. Hyperphenylalaninemias genotyping: Results of over 60 years of history in Lombardy, Italy. Endocrinol Diabetes Metab 2023; 6:e396. [PMID: 36537053 PMCID: PMC10000623 DOI: 10.1002/edm2.396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/11/2022] [Accepted: 11/23/2022] [Indexed: 03/11/2023] Open
Abstract
BACKGROUND Hyperphenylalaninemias (HPA) are due to several gene mutations, of which the PAH gene is the most frequently involved. Prevalence and incidence of disease vary between populations, with genotype/phenotype correlations not always capable to correctly predict disease severity. The aim of this study was to give an overview of PAH mutations among one of the largest cohort of patients among Europe, born in Lombardy (Italy) starting from late 1970 s and including over a 60 years of activity; furthermore, to evaluate and discuss identified genotype/phenotype correlations and related reliability. PATIENTS/METHODS Eight hundred and twenty-six HPA patients in current follow-up at the San Paolo Hospital in Milan (Italy) were retrospectively reviewed, including molecular results and allelic phenotype and genotype values (attributed on the basis of the APV/GPV system) to verify genotype-phenotype correlations. RESULTS A total of 166 different PAH variants were reviewed; of those, seven variants were identified as not previously described in literature. Most frequently reported variant was p.Ala403Val, followed by p.Arg261Gln, p.Val245Ala, IVS10-11 g>a, p.Tyr414Cys and p.Leu48Ser. Phenotype prediction, based on APV/GPV, matched the actual phenotype in most cases, but not always. CONCLUSION/DISCUSSION The cohort of patients included in this study constitute a representative sample of the HPA population worldwide. Studies on this sample may allow to improve clinical and genetic evaluation performances for affected patients, consequently to develop personalized medicine interventions and provide more precise indications on the correct treatment approach based on the accumulated evidence, also in light of a prognostically reliable but not always conclusive APV/GPV system.
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Affiliation(s)
- Valentina Rovelli
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Graziella Cefalo
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Vittoria Ercoli
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Juri Zuvadelli
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Turri Olivia
- Department of Laboratory Diagnostic TechnologiesSan Paolo Hospital, ASST Santi Paolo e CarloMilanItaly
| | - Daniela Graziani
- Department of Laboratory Diagnostic TechnologiesSan Paolo Hospital, ASST Santi Paolo e CarloMilanItaly
| | - Alberti Luisella
- Regional Laboratory of Newborn Screening, Department of Women, Mothers and Neonatal Care, Children's Hospital “V. Buzzi”ASST Fatebenefratelli SaccoMilanItaly
| | - Davide Bassi
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Alice Re Dionigi
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Raed Selmi
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Sabrina Paci
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Elisabetta Salvatici
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
| | - Giuseppe Banderali
- Clinical Department of Pediatrics, Inborn Errors of Metabolism Unit, San Paolo Hospital, ASST Santi Paolo e CarloUniversity of MilanMilanItaly
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2
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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: 14] [Impact Index Per Article: 14.0] [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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3
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Klaessens S, Stroobant V, De Plaen E, Van den Eynde BJ. Systemic tryptophan homeostasis. Front Mol Biosci 2022; 9:897929. [PMID: 36188218 PMCID: PMC9515494 DOI: 10.3389/fmolb.2022.897929] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 08/01/2022] [Indexed: 11/27/2022] Open
Abstract
Tryptophan is an essential amino acid, which is not only a building block for protein synthesis, but also a precursor for the biosynthesis of co-enzymes and neuromodulators, such as NAD/NADP(H), kynurenic acid, melatonin and serotonin. It also plays a role in immune homeostasis, as local tryptophan catabolism impairs T-lymphocyte mediated immunity. Therefore, tryptophan plasmatic concentration needs to be stable, in spite of large variations in dietary supply. Here, we review the main checkpoints accounting for tryptophan homeostasis, including absorption, transport, metabolism and elimination, and we discuss the physiopathology of disorders associated with their dysfunction. Tryptophan is catabolized along the kynurenine pathway through the action of two enzymes that mediate the first and rate-limiting step of the pathway: indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO). While IDO1 expression is restricted to peripheral sites of immune modulation, TDO is massively expressed in the liver and accounts for 90% of tryptophan catabolism. Recent data indicated that the stability of the TDO protein is regulated by tryptophan and that this regulation allows a tight control of tryptophanemia. TDO is stabilized when tryptophan is abundant in the plasma, resulting in rapid degradation of dietary tryptophan. In contrast, when tryptophan is scarce, TDO is degraded by the proteasome to avoid excessive tryptophan catabolism. This is triggered by the unmasking of a degron in a non-catalytic tryptophan-binding site, resulting in TDO ubiquitination by E3 ligase SKP1-CUL1-F-box. Deficiency in TDO or in the hepatic aromatic transporter SLC16A10 leads to severe hypertryptophanemia, which can disturb immune and neurological homeostasis.
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Affiliation(s)
- Simon Klaessens
- Ludwig Institute for Cancer Research, Brussels, Belgium
- de Duve Institute, UCLouvain, Brussels, Belgium
- *Correspondence: Simon Klaessens, ; Benoit J. Van den Eynde,
| | - Vincent Stroobant
- Ludwig Institute for Cancer Research, Brussels, Belgium
- de Duve Institute, UCLouvain, Brussels, Belgium
| | - Etienne De Plaen
- Ludwig Institute for Cancer Research, Brussels, Belgium
- de Duve Institute, UCLouvain, Brussels, Belgium
| | - Benoit J. Van den Eynde
- Ludwig Institute for Cancer Research, Brussels, Belgium
- de Duve Institute, UCLouvain, Brussels, Belgium
- Walloon Excellence in Life Sciences and Biotechnology, Wavre, Belgium
- Nuffield Department of Clinical Medicine, Ludwig Institute for Cancer Research, University of Oxford, Oxford, United Kingdom
- *Correspondence: Simon Klaessens, ; Benoit J. Van den Eynde,
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4
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Deubiquitinase USP19 extends the residual enzymatic activity of phenylalanine hydroxylase variants. Sci Rep 2022; 12:14243. [PMID: 35987969 PMCID: PMC9392723 DOI: 10.1038/s41598-022-18656-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 08/17/2022] [Indexed: 11/09/2022] Open
Abstract
Phenylalanine hydroxylase (PAH) is a key enzyme in mammals that maintains the phenylalanine (Phe) concentration at an appropriate physiological level. Some genetic mutations in the PAH gene lead to destabilization of the PAH enzyme, leading to phenylketonuria (PKU). Destabilized PAH variants can have a certain amount of residual enzymatic activity that is sufficient for metabolism of Phe. However, accelerated degradation of those variants can lead to insufficient amounts of cellular PAH protein. The optimal protein level of PAH in cells is regulated by a balancing act between E3 ligases and deubiquitinating enzymes (DUBs). In this work, we analyzed the protein expression and stability of two PKU-linked PAH protein variants, R241C and R243Q, prevalent in the Asian population. We found that the tested PAH variants were highly ubiquitinated and thus targeted for rapid protein degradation. We demonstrated that USP19, a DUB that interacts with both PAH variants, plays a regulatory role by extending their half-lives. The deubiquitinating activity of USP19 prevents protein degradation and increases the abundance of both PAH protein variants. Thus, our study reveals a novel mechanism by which deubiquitinating activity of USP19 extends the residual enzymatic activity of PAH variants.
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5
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Alves MMS, Leandro P, Mertens HDT, Pereiro AB, Archer M. Impact of Fluorinated Ionic Liquids on Human Phenylalanine Hydroxylase-A Potential Drug Delivery System. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:893. [PMID: 35335706 PMCID: PMC8950220 DOI: 10.3390/nano12060893] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/16/2022]
Abstract
Phenylketonuria (PKU) is an autosomal recessive disease caused by deficient activity of human phenylalanine hydroxylase (hPAH), which can lead to neurologic impairments in untreated patients. Although some therapies are already available for PKU, these are not without drawbacks. Enzyme-replacement therapy through the delivery of functional hPAH could be a promising strategy. In this work, biophysical methods were used to evaluate the potential of [N1112(OH)][C4F9SO3], a biocompatible fluorinated ionic liquid (FIL), as a delivery system of hPAH. The results herein presented show that [N1112(OH)][C4F9SO3] spontaneously forms micelles in a solution that can encapsulate hPAH. This FIL has no significant effect on the secondary structure of hPAH and is able to increase its enzymatic activity, despite the negative impact on protein thermostability. The influence of [N1112(OH)][C4F9SO3] on the complex oligomerization equilibrium of hPAH was also assessed.
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Affiliation(s)
- Márcia M. S. Alves
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal;
- LAQV, REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT NOVA), 2829-516 Caparica, Portugal
| | - Paula Leandro
- Research Institute for Medicines (iMed.Ulisboa) and Department of Pharmaceutical Sciences and Medicines, Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal;
| | - Haydyn D. T. Mertens
- European Molecular Biology Lamboratory (EMBL), Hamburg Unit c/o Deutches Elektronen Synchrotron (DESY), D-22607 Hamburg, Germany;
| | - Ana B. Pereiro
- LAQV, REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT NOVA), 2829-516 Caparica, Portugal
| | - Margarida Archer
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal;
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6
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Manek R, Zhang YV, Berthelette P, Hossain M, Cornell CS, Gans J, Anarat-Cappillino G, Geller S, Jackson R, Yu D, Singh K, Ryan S, Bangari DS, Xu EY, Kyostio-Moore SRM. Blood phenylalanine reduction reverses gene expression changes observed in a mouse model of phenylketonuria. Sci Rep 2021; 11:22886. [PMID: 34819582 PMCID: PMC8613214 DOI: 10.1038/s41598-021-02267-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 11/09/2021] [Indexed: 12/02/2022] Open
Abstract
Phenylketonuria (PKU) is a genetic deficiency of phenylalanine hydroxylase (PAH) in liver resulting in blood phenylalanine (Phe) elevation and neurotoxicity. A pegylated phenylalanine ammonia lyase (PEG-PAL) metabolizing Phe into cinnamic acid was recently approved as treatment for PKU patients. A potentially one-time rAAV-based delivery of PAH gene into liver to convert Phe into tyrosine (Tyr), a normal way of Phe metabolism, has now also entered the clinic. To understand differences between these two Phe lowering strategies, we evaluated PAH and PAL expression in livers of PAHenu2 mice on brain and liver functions. Both lowered brain Phe and increased neurotransmitter levels and corrected animal behavior. However, PAL delivery required dose optimization, did not elevate brain Tyr levels and resulted in an immune response. The effect of hyperphenylalanemia on liver functions in PKU mice was assessed by transcriptome and proteomic analyses. We observed an elevation in Cyp4a10/14 proteins involved in lipid metabolism and upregulation of genes involved in cholesterol biosynthesis. Majority of the gene expression changes were corrected by PAH and PAL delivery though the role of these changes in PKU pathology is currently unclear. Taken together, here we show that blood Phe lowering strategy using PAH or PAL corrects both brain pathology as well as previously unknown lipid metabolism associated pathway changes in liver.
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Affiliation(s)
- Rachna Manek
- Genomic Medicine Unit, Sanofi, Framingham, MA, USA.
| | - Yao V Zhang
- Genomic Medicine Unit, Sanofi, Framingham, MA, USA
| | | | | | | | - Joseph Gans
- Translational Sciences, Sanofi, Framingham, MA, USA
| | | | - Sarah Geller
- Pre-Development Sciences NA, Analytical R&D, Sanofi, Framingham, MA, USA
| | | | - Dan Yu
- Genomic Medicine Unit, Sanofi, Framingham, MA, USA
| | - Kuldeep Singh
- Global Discovery Pathology, Sanofi, Framingham, MA, USA
| | - Sue Ryan
- Global Discovery Pathology, Sanofi, Framingham, MA, USA
| | | | - Ethan Y Xu
- Translational Sciences, Sanofi, Framingham, MA, USA
- Excision BioTherapeutics, Cambridge, MA, USA
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7
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Solomon EI, DeWeese DE, Babicz JT. Mechanisms of O 2 Activation by Mononuclear Non-Heme Iron Enzymes. Biochemistry 2021; 60:3497-3506. [PMID: 34266238 PMCID: PMC8768060 DOI: 10.1021/acs.biochem.1c00370] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Two major subclasses of mononuclear non-heme ferrous enzymes use two electron-donating organic cofactors (α-ketoglutarate or pterin) to activate O2 to form FeIV═O intermediates that further react with their substrates through hydrogen atom abstraction or electrophilic aromatic substitution. New spectroscopic methodologies have been developed, enabling the study of the active sites in these enzymes and their oxygen intermediates. Coupled to electronic structure calculations, the results of these spectroscopies provide fundamental insight into mechanism. This Perspective summarizes the results of these studies in elucidating the mechanism of dioxygen activation to form the FeIV═O intermediate and the geometric and electronic structure of this intermediate that enables its high reactivity and selectivity in product formation.
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Affiliation(s)
- Edward I. Solomon
- Department of Chemistry, Stanford University, 333 Campus Dr. Stanford, CA, 94305, United States,SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, 94025, United States
| | - Dory E. DeWeese
- Department of Chemistry, Stanford University, 333 Campus Dr. Stanford, CA, 94305, United States
| | - Jeffrey T. Babicz
- Department of Chemistry, Stanford University, 333 Campus Dr. Stanford, CA, 94305, United States
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8
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Zhang Z, Ma D, Wang X, Wang Y, Li Y, Yang P, Sun Y, Jiang T, Xu Z. A joint method for the screening of pharmacological chaperones for phenylalanine hydroxylase. Org Biomol Chem 2021; 19:5827-5835. [PMID: 34113943 DOI: 10.1039/d1ob00638j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phenylalanine hydroxylase (PAH) deficiency (PAHD) is an autosomal recessive disorder that causes severe injury to the nervous system, the treatment of which mainly depends on dietary therapy. The limited treatment options for PAHD are an incentive to develop new methods to identify more efficient therapeutic drugs, such as agonists which could improve PAH activity. In this study, we aimed to establish a rapid and convenient method for the screening and verification of PAH agonists. We compared fluorospectrophotometry and tandem mass spectrometry for detection of enzymatic formation of tyrosine, finding that the latter was a more sensitive method. We optimized immunoprecipitation purification conditions and measurement conditions of PAH activity. The optimal ratio between PAH protein and magnetic beads was 500 μg protein per 20 μL beads, and the optimized conditions for the detection of PAH enzymatic activity included the presence of 75 μM coenzyme ((6R)-l-erythro-5,6,7,8-tetrahydrobiopterin) and 30 min reaction time. Based on virtual screening, we screened ten candidate agonists from the FDA drug library. Three of these (nefopam, fluocinonide, and risperidone) were found to activate the enzyme in a dose-dependent manner (0.1-10 μM) by the joint method. We tested the efficacy of the three agonists on three PAH mutations (p.I65T, p.H107R, and p.D101N) that influence enzyme activity, and found that risperidone could specifically activate D101N-mutated enzyme. In conclusion, we established a joint method that is highly reliable, cost-effective, labor-saving, and time-saving. And we also found a specific agonist for D101N-mutated PAH by this joint method which may assist the development of clinical treatment for PAHD patients with different enzyme deficiencies.
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Affiliation(s)
- Zhilei Zhang
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
| | - Dingyuan Ma
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
| | - Xin Wang
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
| | - Yanyun Wang
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
| | - Yahong Li
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
| | - Peiyin Yang
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
| | - Yun Sun
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
| | - Tao Jiang
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
| | - Zhengfeng Xu
- The affiliated Obstetrics and Gynecology Hospital with Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Center of Genetic Medicine, Nanjing 210004, Jiangsu, P.R. China.
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9
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Conde-Giménez M, Sancho J. Unravelling the Complex Denaturant and Thermal-Induced Unfolding Equilibria of Human Phenylalanine Hydroxylase. Int J Mol Sci 2021; 22:ijms22126539. [PMID: 34207146 PMCID: PMC8234983 DOI: 10.3390/ijms22126539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/11/2021] [Accepted: 06/15/2021] [Indexed: 12/27/2022] Open
Abstract
Human phenylalanine hydroxylase (PAH) is a metabolic enzyme involved in the catabolism of L-Phe in liver. Loss of conformational stability and decreased enzymatic activity in PAH variants result in the autosomal recessive disorder phenylketonuria (PKU), characterized by developmental and psychological problems if not treated early. One current therapeutic approach to treat PKU is based on pharmacological chaperones (PCs), small molecules that can displace the folding equilibrium of unstable PAH variants toward the native state, thereby rescuing the physiological function of the enzyme. Understanding the PAH folding equilibrium is essential to develop new PCs for different forms of the disease. We investigate here the urea and the thermal-induced denaturation of full-length PAH and of a truncated form lacking the regulatory and the tetramerization domains. For either protein construction, two distinct transitions are seen in chemical denaturation followed by fluorescence emission, indicating the accumulation of equilibrium unfolding intermediates where the catalytic domains are partly unfolded and dissociated from each other. According to analytical centrifugation, the chemical denaturation intermediates of either construction are not well-defined species but highly polydisperse ensembles of protein aggregates. On the other hand, each protein construction similarly shows two transitions in thermal denaturation measured by fluorescence or differential scanning calorimetry, also indicating the accumulation of equilibrium unfolding intermediates. The similar temperatures of mid denaturation of the two constructions, together with their apparent lack of response to protein concentration, indicate the catalytic domains are unfolded in the full-length PAH thermal intermediate, where they remain associated. That the catalytic domain unfolds in the first thermal transition is relevant for the choice of PCs identified in high throughput screening of chemical libraries using differential scanning fluorimetry.
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Affiliation(s)
- María Conde-Giménez
- Departamento de Bioquímica y Biología Molecular y Celular, Biocomputation and Complex Systems Physics Institute (BIFI)-Joint Units: BIFI-IQFR (CSIC) and GBsC-CSIC, University of Zaragoza, 50009 Zaragoza, Spain;
| | - Javier Sancho
- Departamento de Bioquímica y Biología Molecular y Celular, Biocomputation and Complex Systems Physics Institute (BIFI)-Joint Units: BIFI-IQFR (CSIC) and GBsC-CSIC, University of Zaragoza, 50009 Zaragoza, Spain;
- Aragon Health Research Institute (IIS Aragón), 50009 Zaragoza, Spain
- Correspondence:
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10
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Arturo EC, Merkel GW, Hansen MR, Lisowski S, Almeida D, Gupta K, Jaffe EK. Manipulation of a cation-π sandwich reveals conformational flexibility in phenylalanine hydroxylase. Biochimie 2021; 183:63-77. [PMID: 33221376 PMCID: PMC9856217 DOI: 10.1016/j.biochi.2020.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/04/2020] [Accepted: 11/10/2020] [Indexed: 01/24/2023]
Abstract
Phenylalanine hydroxylase (PAH) is an allosteric enzyme that maintains phenylalanine (Phe) below neurotoxic levels; its failure results in phenylketonuria, an inborn error of amino acid metabolism. Wild type (WT) PAH equilibrates among resting-state (RS-PAH) and activated (A-PAH) conformations, whose equilibrium position depends upon allosteric Phe binding. The RS-PAH conformation of WT rat PAH (rPAH) contains a cation-π sandwich involving Phe80 that cannot exist in the A-PAH conformation. Phe80 variants F80A, F80D, F80L, and F80R were prepared and evaluated using native PAGE, size exclusion chromatography, ion exchange behavior, intrinsic protein fluorescence, enzyme kinetics, and limited proteolysis, each as a function of [Phe]. Like WT rPAH, F80A and F80D show allosteric activation by Phe while F80L and F80R are constitutively active. Maximal activity of all variants suggests relief of a rate-determining conformational change. Limited proteolysis of WT rPAH (minus Phe) reveals facile cleavage within a 4-helix bundle that is buried in the RS-PAH tetramer interface, reflecting dynamic dissociation of that tetramer. This cleavage is not seen for the Phe80 variants, which all show proteolytic hypersensitivity in a linker that repositions during the RS-PAH to A-PAH interchange. Hypersensitivity is corrected by addition of Phe such that all variants become like WT rPAH and achieve the A-PAH conformation. Thus, manipulation of Phe80 perturbs the conformational space sampled by PAH, increasing sampling of on-pathway intermediates in the RS-PAH and A-PAH interchange. The behavior of the Phe80 variants mimics that of disease-associated R68S and suggests a molecular basis for proteolytic susceptibility in PKU-associated human PAH variants.
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Affiliation(s)
- Emilia C. Arturo
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111,Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102
| | - George W. Merkel
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Michael R. Hansen
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Sophia Lisowski
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Deeanne Almeida
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Kushol Gupta
- Department pf Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Eileen K. Jaffe
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111,To whom correspondence should be addressed: Eileen K. Jaffe: Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA 19111; ; Tel.(215) 728-3695; Fax. (215) 728-2412
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11
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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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12
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Jaffe EK. Wrangling Shape-Shifting Morpheeins to Tackle Disease and Approach Drug Discovery. Front Mol Biosci 2020; 7:582966. [PMID: 33330623 PMCID: PMC7729013 DOI: 10.3389/fmolb.2020.582966] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/26/2020] [Indexed: 12/15/2022] Open
Abstract
Homo-multimeric proteins that can come apart, change shape, and reassemble differently with functional consequences have been called morpheeins and/or transformers; these provide a largely unexplored context for understanding disease and developing allosteric therapeutics. This article describes such proteins within the context of protein structure dynamics, provides one detailed example related to an inborn error of metabolism and potential herbicide development, and describes the context for applying these ideas for understanding disease and designing bioactive molecules, such as therapeutics.
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Affiliation(s)
- Eileen K Jaffe
- Fox Chase Cancer Center, Philadelphia, PA, United States
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13
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ProtCID: a data resource for structural information on protein interactions. Nat Commun 2020; 11:711. [PMID: 32024829 PMCID: PMC7002494 DOI: 10.1038/s41467-020-14301-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 12/13/2019] [Indexed: 12/16/2022] Open
Abstract
Structural information on the interactions of proteins with other molecules is plentiful, and for some proteins and protein families, there may be 100s of available structures. It can be very difficult for a scientist who is not trained in structural bioinformatics to access this information comprehensively. Previously, we developed the Protein Common Interface Database (ProtCID), which provided clusters of the interfaces of full-length protein chains as a means of identifying biological assemblies. Because proteins consist of domains that act as modular functional units, we have extended the analysis in ProtCID to the individual domain level. This has greatly increased the number of large protein-protein clusters in ProtCID, enabling the generation of hypotheses on the structures of biological assemblies of many systems. The analysis of domain families allows us to extend ProtCID to the interactions of domains with peptides, nucleic acids, and ligands. ProtCID provides complete annotations and coordinate sets for every cluster. The authors previously developed the Protein Common Interface Database (ProtCID), which compares and clusters the interfaces of pairs of full-length protein chains with defined Pfam domain architectures in different PDB entries to identify biological assemblies. Here the authors extend ProtCID to the clustering of domain-domain interactions that also allows analyzing domain interactions with peptides, nucleic acids, and ligands.
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14
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Porphobilinogen synthase: An equilibrium of different assemblies in human health. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 169:85-104. [PMID: 31952692 DOI: 10.1016/bs.pmbts.2019.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Porphobilinogen synthase (PBGS) is an essential enzyme that catalyzes an early step in heme biosynthesis. An unexpected human PBGS quaternary structure dynamic drove the definition of morpheeins, which are protein multimers that dissociate, change shape, and re-assemble differently with functional consequences. Each PBGS monomer has two domains that can reposition through a hinge motion. Human PBGS exists in an equilibrium among high activity octamer, low activity hexamer, and low mole-fraction dimer in which the hinge motion occurs. The dimer conformation dictates the multimer architecture. An octamer-specific inter-subunit interaction responds to pH, resulting in a pH-dependence to the octamer-hexamer equilibrium. An inborn error of metabolism, ALAD porphyria, is caused by single amino acid substitutions that stabilize the hexamer relative to octamer. Drugs that stabilize the PBGS hexamer result in a drug side effect that can exacerbate porphyria. PBGS is essential for all organisms that require respiration, photosynthesis, or methanogenesis. Consequently, phylogenetic variation in PBGS multimerization equilibria provides insight into how Nature has harnessed oligomeric variation in the control of protein function. The dynamic multimerization of PBGS revealed the morpheein mechanism for allostery, a structural basis for inborn errors of metabolism, a quaternary structure focus for drug discovery and/or drug side effects, and a pathway toward new antibiotics or herbicides. The fortuitous discovery of PBGS quaternary structure dynamics arose from characterization of a low-activity single amino acid variant that dramatically stabilized the hexamer, whose existence had previously gone unnoticed.
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15
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Tomé CS, Lopes RR, Sousa PMF, Amaro MP, Leandro J, Mertens HDT, Leandro P, Vicente JB. Structure of full-length wild-type human phenylalanine hydroxylase by small angle X-ray scattering reveals substrate-induced conformational stability. Sci Rep 2019; 9:13615. [PMID: 31541188 PMCID: PMC6754429 DOI: 10.1038/s41598-019-49944-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/03/2019] [Indexed: 01/30/2023] Open
Abstract
Human phenylalanine hydroxylase (hPAH) hydroxylates L-phenylalanine (L-Phe) to L-tyrosine, a precursor for neurotransmitter biosynthesis. Phenylketonuria (PKU), caused by mutations in PAH that impair PAH function, leads to neurological impairment when untreated. Understanding the hPAH structural and regulatory properties is essential to outline PKU pathophysiological mechanisms. Each hPAH monomer comprises an N-terminal regulatory, a central catalytic and a C-terminal oligomerisation domain. To maintain physiological L-Phe levels, hPAH employs complex regulatory mechanisms. Resting PAH adopts an auto-inhibited conformation where regulatory domains block access to the active site. L-Phe-mediated allosteric activation induces a repositioning of the regulatory domains. Since a structure of activated wild-type hPAH is lacking, we addressed hPAH L-Phe-mediated conformational changes and report the first solution structure of the allosterically activated state. Our solution structures obtained by small-angle X-ray scattering support a tetramer with distorted P222 symmetry, where catalytic and oligomerisation domains form a core from which regulatory domains protrude, positioning themselves close to the active site entrance in the absence of L-Phe. Binding of L-Phe induces a large movement and dimerisation of regulatory domains, exposing the active site. Activated hPAH is more resistant to proteolytic cleavage and thermal denaturation, suggesting that the association of regulatory domains stabilises hPAH.
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Affiliation(s)
- Catarina S Tomé
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | - Raquel R Lopes
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Pedro M F Sousa
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
| | - Mariana P Amaro
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - João Leandro
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
- Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Paula Leandro
- Research Institute for Medicines (iMed.ULisboa) and Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal.
| | - João B Vicente
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
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16
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Peacock RB, Hicks CW, Walker AM, Dewing SM, Lewis KM, Abboud JC, Stewart SWA, Kang C, Watson JM. Structural and Functional Characterization of Dynamic Oligomerization in Burkholderia cenocepacia HMG-CoA Reductase. Biochemistry 2019; 58:3960-3970. [PMID: 31469273 DOI: 10.1021/acs.biochem.9b00494] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMGR), in most organisms, catalyzes the four-electron reduction of the thioester (S)-HMG-CoA to the primary alcohol (R)-mevalonate, utilizing NADPH as the hydride donor. In some organisms, including the opportunistic lung pathogen Burkholderia cenocepacia, it catalyzes the reverse reaction, utilizing NAD+ as a hydride acceptor in the oxidation of mevalonate. B. cenocepacia HMGR has been previously shown to exist as an ensemble of multiple non-additive oligomeric states, each with different levels of enzymatic activity, suggesting that the enzyme exhibits characteristics of the morpheein model of allostery. We have characterized a number of factors, including pH, substrate concentration, and enzyme concentration, that modulate the structural transitions that influence the interconversion among the multiple oligomers. We have also determined the crystal structure of B. cenocepacia HMGR in the hexameric state bound to coenzyme A and ADP. This hexameric assembly provides important clues about how the transition among oligomers might occur, and why B. cenocepacia HMGR, unique among characterized HMGRs, exhibits morpheein-like behavior.
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Affiliation(s)
- Riley B Peacock
- Department of Chemistry and Biochemistry , Gonzaga University , Spokane , Washington 99258 , United States
| | - Chad W Hicks
- Department of Chemistry and Biochemistry , Gonzaga University , Spokane , Washington 99258 , United States
| | - Alexander M Walker
- Department of Chemistry , Washington State University , Pullman , Washington 99164 , United States
| | - Sophia M Dewing
- Department of Chemistry and Biochemistry , Gonzaga University , Spokane , Washington 99258 , United States
| | - Kevin M Lewis
- Department of Chemistry , Washington State University , Pullman , Washington 99164 , United States
| | - Jean-Claude Abboud
- Department of Chemistry and Biochemistry , Gonzaga University , Spokane , Washington 99258 , United States
| | - Samuel W A Stewart
- Department of Chemistry and Biochemistry , Gonzaga University , Spokane , Washington 99258 , United States
| | - ChulHee Kang
- Department of Chemistry , Washington State University , Pullman , Washington 99164 , United States
| | - Jeffrey M Watson
- Department of Chemistry and Biochemistry , Gonzaga University , Spokane , Washington 99258 , United States
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17
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Arturo EC, Gupta K, Hansen MR, Borne E, Jaffe EK. Biophysical characterization of full-length human phenylalanine hydroxylase provides a deeper understanding of its quaternary structure equilibrium. J Biol Chem 2019; 294:10131-10145. [PMID: 31076506 PMCID: PMC6664189 DOI: 10.1074/jbc.ra119.008294] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/09/2019] [Indexed: 11/06/2022] Open
Abstract
Dysfunction of human phenylalanine hydroxylase (hPAH, EC 1.14.16.1) is the primary cause of phenylketonuria, the most common inborn error of amino acid metabolism. The dynamic domain rearrangements of this multimeric protein have thwarted structural study of the full-length form for decades, until now. In this study, a tractable C29S variant of hPAH (C29S) yielded a 3.06 Å resolution crystal structure of the tetrameric resting-state conformation. We used size-exclusion chromatography in line with small-angle X-ray scattering (SEC-SAXS) to analyze the full-length hPAH solution structure both in the presence and absence of Phe, which serves as both substrate and allosteric activators. Allosteric Phe binding favors accumulation of an activated PAH tetramer conformation, which is biophysically distinct in solution. Protein characterization with enzyme kinetics and intrinsic fluorescence revealed that the C29S variant and hPAH are otherwise equivalent in their response to Phe, further supported by their behavior on various chromatography resins and by analytical ultracentrifugation. Modeling of resting-state and activated forms of C29S against SAXS data with available structural data created and evaluated several new models for the transition between the architecturally distinct conformations of PAH and highlighted unique intra- and inter-subunit interactions. Three best-fitting alternative models all placed the allosteric Phe-binding module 8-10 Å farther from the tetramer center than do all previous models. The structural insights into allosteric activation of hPAH reported here may help inform ongoing efforts to treat phenylketonuria with novel therapeutic approaches.
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Affiliation(s)
- Emilia C Arturo
- From the Molecular Therapeutics Program, Fox Chase Cancer Center, Temple University Health Systems, Philadelphia, Pennsylvania 19111
- the Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, and
| | - Kushol Gupta
- the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Michael R Hansen
- From the Molecular Therapeutics Program, Fox Chase Cancer Center, Temple University Health Systems, Philadelphia, Pennsylvania 19111
| | - Elias Borne
- From the Molecular Therapeutics Program, Fox Chase Cancer Center, Temple University Health Systems, Philadelphia, Pennsylvania 19111
| | - Eileen K Jaffe
- From the Molecular Therapeutics Program, Fox Chase Cancer Center, Temple University Health Systems, Philadelphia, Pennsylvania 19111,
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18
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Ge Y, Borne E, Stewart S, Hansen MR, Arturo EC, Jaffe EK, Voelz VA. Simulations of the regulatory ACT domain of human phenylalanine hydroxylase (PAH) unveil its mechanism of phenylalanine binding. J Biol Chem 2018; 293:19532-19543. [PMID: 30287685 DOI: 10.1074/jbc.ra118.004909] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/17/2018] [Indexed: 12/20/2022] Open
Abstract
Phenylalanine hydroxylase (PAH) regulates phenylalanine (Phe) levels in mammals to prevent neurotoxicity resulting from high Phe concentrations as observed in genetic disorders leading to hyperphenylalaninemia and phenylketonuria. PAH senses elevated Phe concentrations by transient allosteric Phe binding to a protein-protein interface between ACT domains of different subunits in a PAH tetramer. This interface is present in an activated PAH (A-PAH) tetramer and absent in a resting-state PAH (RS-PAH) tetramer. To investigate this allosteric sensing mechanism, here we used the GROMACS molecular dynamics simulation suite on the Folding@home computing platform to perform extensive molecular simulations and Markov state model (MSM) analysis of Phe binding to ACT domain dimers. These simulations strongly implicated a conformational selection mechanism for Phe association with ACT domain dimers and revealed protein motions that act as a gating mechanism for Phe binding. The MSMs also illuminate a highly mobile hairpin loop, consistent with experimental findings also presented here that the PAH variant L72W does not shift the PAH structural equilibrium toward the activated state. Finally, simulations of ACT domain monomers are presented, in which spontaneous transitions between resting-state and activated conformations are observed, also consistent with a mechanism of conformational selection. These mechanistic details provide detailed insight into the regulation of PAH activation and provide testable hypotheses for the development of new allosteric effectors to correct structural and functional defects in PAH.
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Affiliation(s)
- Yunhui Ge
- From the Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Elias Borne
- Fox Chase Cancer Center, Temple University Health System, Philadelphia, Pennsylvania 19111, and
| | - Shannon Stewart
- Fox Chase Cancer Center, Temple University Health System, Philadelphia, Pennsylvania 19111, and
| | - Michael R Hansen
- Fox Chase Cancer Center, Temple University Health System, Philadelphia, Pennsylvania 19111, and
| | - Emilia C Arturo
- Fox Chase Cancer Center, Temple University Health System, Philadelphia, Pennsylvania 19111, and.,Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Eileen K Jaffe
- Fox Chase Cancer Center, Temple University Health System, Philadelphia, Pennsylvania 19111, and
| | - Vincent A Voelz
- From the Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122,
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19
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Brasil S, Briso-Montiano A, Gámez A, Underhaug J, Flydal M, Desviat L, Merinero B, Ugarte M, Martinez A, Pérez B. New perspectives for pharmacological chaperoning treatment in methylmalonic aciduria cblB type. Biochim Biophys Acta Mol Basis Dis 2018; 1864:640-648. [DOI: 10.1016/j.bbadis.2017.11.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/17/2017] [Accepted: 11/27/2017] [Indexed: 02/08/2023]
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20
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Kim HL, Ryu HC, Park YS. Quantitative analysis by flow cytometry of green fluorescent protein-tagged human phenylalanine hydroxylase expressed in Dictyostelium. Pteridines 2017. [DOI: 10.1515/pterid-2017-0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
We have developed a fluorescence assay system to monitor the protein levels of human phenylalanine hydroxylase (hPAH). Wild-type (WT) and three mutant hPAHs (I65T, L255V, and S349L) were expressed as green fluorescent protein (GFP)-tagged forms in a PAH knockout mutant (pah
−) of Dictyostelium discoideum Ax2. The fluorescence-activated cell sorting (FACS) analysis showed that the GFP positive cells were the most frequent in WT but were rare in pah
−, demonstrating the successful expression of GFP-tagged hPAHs in Dictyostelium. The fluorescence levels of mutants relative to WT were higher than expected from the protein amounts determined from the non-tagged forms, probably due to the presence of the N-terminal GFP. However, treatment of the cells with cumene hydroperoxide, which is known to accelerate protein degradation, decreased fluorescence levels, suggesting that protein stability changes in individual mutations can be monitored by FACS analysis. For an evaluation study, a putative pharmacological chaperone effect of yeast extract on S349L was examined by Western blot and FACS analysis. Both the protein amount and the fluorescence levels were increased by yeast extract, supporting that the FACS analysis could replace the time- and labor-consuming procedures such as the Western blot and cell culture. The fluorescence-based cell assay system may be valuable for the high-throughput screening of pharmacological chaperones for phenylketonuria mutations.
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Affiliation(s)
- Hye-Lim Kim
- School of Biological Sciences , Inje University , Gimhae 50834 , Republic of Korea
| | - Hyun-Chul Ryu
- School of Biological Sciences , Inje University , Gimhae 50834 , Republic of Korea
| | - Young Shik Park
- School of Biological Sciences , Inje University , Gimhae 50834 , Republic of Korea
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21
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Jaffe EK. New protein structures provide an updated understanding of phenylketonuria. Mol Genet Metab 2017; 121:289-296. [PMID: 28645531 PMCID: PMC5549558 DOI: 10.1016/j.ymgme.2017.06.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 06/08/2017] [Indexed: 11/16/2022]
Abstract
Phenylketonuria (PKU) and less severe hyperphenylalaninemia (HPA) constitute the most common inborn error of amino acid metabolism, and is most often caused by defects in phenylalanine hydroxylase (PAH) function resulting in accumulation of Phe to neurotoxic levels. Despite the success of dietary intervention in preventing permanent neurological damage, individuals living with PKU clamor for additional non-dietary therapies. The bulk of disease-associated mutations are PAH missense variants, which occur throughout the entire 452 amino acid human PAH protein. While some disease-associated mutations affect protein structure (e.g. truncations) and others encode catalytically dead variants, most have been viewed as defective in protein folding/stability. Here we refine this view to address how PKU-associated missense variants can perturb the equilibrium among alternate native PAH structures (resting-state PAH and activated PAH), thus shifting the tipping point of this equilibrium to a neurotoxic Phe concentration. This refined view of PKU introduces opportunities for the design or discovery of therapeutic pharmacological chaperones that can help restore the tipping point to healthy Phe levels and how such a therapeutic might work with or without the inhibitory pharmacological chaperone BH4. Dysregulation of an equilibrium of architecturally distinct native PAH structures departs from the concept of "misfolding", provides an updated understanding of PKU, and presents an enhanced foundation for understanding genotype/phenotype relationships.
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Affiliation(s)
- Eileen K Jaffe
- Fox Chase Cancer Center - Temple University Health System, 333 Cottman Ave, Philadelphia, PA 19111, USA.
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22
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Abstract
X-ray scattering is uniquely suited to the study of disordered systems and thus has the potential to provide insight into dynamic processes where diffraction methods fail. In particular, while X-ray crystallography has been a staple of structural biology for more than half a century and will continue to remain so, a major limitation of this technique has been the lack of dynamic information. Solution X-ray scattering has become an invaluable tool in structural and mechanistic studies of biological macromolecules where large conformational changes are involved. Such systems include allosteric enzymes that play key roles in directing metabolic fluxes of biochemical pathways, as well as large, assembly-line type enzymes that synthesize secondary metabolites with pharmaceutical applications. Furthermore, crystallography has the potential to provide information on protein dynamics via the diffuse scattering patterns that are overlaid with Bragg diffraction. Historically, these patterns have been very difficult to interpret, but recent advances in X-ray detection have led to a renewed interest in diffuse scattering analysis as a way to probe correlated motions. Here, we will review X-ray scattering theory and highlight recent advances in scattering-based investigations of protein solutions and crystals, with a particular focus on complex enzymes.
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Affiliation(s)
- Steve P Meisburger
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - William C Thomas
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Maxwell B Watkins
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Nozomi Ando
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
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23
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Huang H, Wang W, Tao YX. Pharmacological chaperones for the misfolded melanocortin-4 receptor associated with human obesity. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2496-2507. [PMID: 28284973 DOI: 10.1016/j.bbadis.2017.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/28/2017] [Accepted: 03/01/2017] [Indexed: 01/01/2023]
Abstract
The melanocortin-4 receptor (MC4R) plays a vital role in regulating energy homeostasis. Mutations in the MC4R cause early-onset severe obesity. The majority of loss of function MC4R mutants are retained intracellularly, many of which are not terminally misfolded and can be stabilized and targeted to the plasma membrane by different chaperones. Some of the mutants might be functional once coaxed to the cell surface. Molecular chaperones and chemical chaperones correct the misfolding of some mutant MC4Rs. However, their therapeutic application is very limited due to their non-specific mechanism of action and, for chemical chaperone, high dosage needed to be effective. Several pharmacological chaperones have been identified for the MC4R and Ipsen 5i and Ipsen 17 are the most potent and efficacious. Here we provide a comprehensive review on how different approaches have been applied to rescue misfolded MC4R mutants. This article is part of a Special Issue entitled: Melanocortin Receptors - edited by Ya-Xiong Tao.
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Affiliation(s)
- Hui Huang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Wei Wang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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24
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Tidemand KD, Christensen HEM, Hoeck N, Harris P, Boesen J, Peters GH. Stabilization of tryptophan hydroxylase 2 by l-phenylalanine-induced dimerization. FEBS Open Bio 2016; 6:987-999. [PMID: 27761358 PMCID: PMC5055035 DOI: 10.1002/2211-5463.12100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/20/2016] [Accepted: 06/29/2016] [Indexed: 12/12/2022] Open
Abstract
Tryptophan hydroxylase 2 (TPH2) catalyses the initial and rate‐limiting step in the biosynthesis of serotonin, which is associated with a variety of disorders such as depression, obsessive compulsive disorder, and schizophrenia. Full‐length TPH2 is poorly characterized due to low purification quantities caused by its inherent instability. Three truncated variants of human TPH2 (rchTPH2; regulatory and catalytic domain, NΔ47‐rchTPH2; truncation of 47 residues in the N terminus of rchTPH2, and chTPH2; catalytic domain) were expressed, purified, and examined for changes in transition temperature, inactivation rate, and oligomeric state. chTPH2 displayed 14‐ and 11‐fold higher half‐lives compared to rchTPH2 and NΔ47‐rchTPH2, respectively. Differential scanning calorimetry experiments demonstrated that this is caused by premature unfolding of the less stable regulatory domain. By differential scanning fluorimetry, the unfolding transitions of rchTPH2 and NΔ47‐rchTPH2 are found to shift from polyphasic to apparent two‐state by the addition of l‐Trp or l‐Phe. Analytical gel filtration revealed that rchTPH2 and NΔ47‐rchTPH2 reside in a monomer–dimer equilibrium which is significantly shifted toward dimer in the presence of l‐Phe. The dimerizing effect induced by l‐Phe is accompanied by a stabilizing effect, which resulted in a threefold increase in half‐lives of rchTPH2 and NΔ47‐rchTPH2. Addition of l‐Phe to the purification buffer significantly increases the purification yields, which will facilitate characterization of hTPH2.
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Affiliation(s)
- Kasper D Tidemand
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | | | - Niclas Hoeck
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Pernille Harris
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Jane Boesen
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
| | - Günther H Peters
- Department of Chemistry Technical University of Denmark Kongens Lyngby Denmark
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25
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Koshiba S, Motoike I, Kojima K, Hasegawa T, Shirota M, Saito T, Saigusa D, Danjoh I, Katsuoka F, Ogishima S, Kawai Y, Yamaguchi-Kabata Y, Sakurai M, Hirano S, Nakata J, Motohashi H, Hozawa A, Kuriyama S, Minegishi N, Nagasaki M, Takai-Igarashi T, Fuse N, Kiyomoto H, Sugawara J, Suzuki Y, Kure S, Yaegashi N, Tanabe O, Kinoshita K, Yasuda J, Yamamoto M. The structural origin of metabolic quantitative diversity. Sci Rep 2016; 6:31463. [PMID: 27528366 PMCID: PMC4985752 DOI: 10.1038/srep31463] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 07/18/2016] [Indexed: 12/21/2022] Open
Abstract
Relationship between structural variants of enzymes and metabolic phenotypes in human population was investigated based on the association study of metabolite quantitative traits with whole genome sequence data for 512 individuals from a population cohort. We identified five significant associations between metabolites and non-synonymous variants. Four of these non-synonymous variants are located in enzymes involved in metabolic disorders, and structural analyses of these moderate non-synonymous variants demonstrate that they are located in peripheral regions of the catalytic sites or related regulatory domains. In contrast, two individuals with larger changes of metabolite levels were also identified, and these individuals retained rare variants, which caused non-synonymous variants located near the catalytic site. These results are the first demonstrations that variant frequency, structural location, and effect for phenotype correlate with each other in human population, and imply that metabolic individuality and susceptibility for diseases may be elicited from the moderate variants and much more deleterious but rare variants.
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Affiliation(s)
- Seizo Koshiba
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Ikuko Motoike
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Information Sciences, Tohoku University, 6-3-09, Aramaki Aza-Aoba, Aoba-ku, Sendai, 980-8579 Japan
| | - Kaname Kojima
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Takanori Hasegawa
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Matsuyuki Shirota
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Tomo Saito
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Daisuke Saigusa
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Inaho Danjoh
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Fumiki Katsuoka
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Soichi Ogishima
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Yosuke Kawai
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Yumi Yamaguchi-Kabata
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Miyuki Sakurai
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan
| | - Sachiko Hirano
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan
| | - Junichi Nakata
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan
| | - Hozumi Motohashi
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Institute of Development, Aging and Cancer, Tohoku University, 4-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Atsushi Hozawa
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Shinichi Kuriyama
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Naoko Minegishi
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Masao Nagasaki
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan.,Graduate School of Information Sciences, Tohoku University, 6-3-09, Aramaki Aza-Aoba, Aoba-ku, Sendai, 980-8579 Japan
| | - Takako Takai-Igarashi
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Nobuo Fuse
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Hideyasu Kiyomoto
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Junichi Sugawara
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Yoichi Suzuki
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Shigeo Kure
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Nobuo Yaegashi
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Osamu Tanabe
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Kengo Kinoshita
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Information Sciences, Tohoku University, 6-3-09, Aramaki Aza-Aoba, Aoba-ku, Sendai, 980-8579 Japan.,Institute of Development, Aging and Cancer, Tohoku University, 4-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Jun Yasuda
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
| | - Masayuki Yamamoto
- Tohoku Medical Megabank organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573 Japan.,Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575 Japan
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26
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Yue WW. From structural biology to designing therapy for inborn errors of metabolism. J Inherit Metab Dis 2016; 39:489-98. [PMID: 27240455 PMCID: PMC4920855 DOI: 10.1007/s10545-016-9923-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 02/09/2016] [Accepted: 02/11/2016] [Indexed: 12/11/2022]
Abstract
At the SSIEM Symposium in Istanbul 2010, I presented an overview of protein structural approaches in the study of inborn errors of metabolism (Yue and Oppermann 2011). Five years on, the field is going strong with new protein structures, uncovered catalytic functions and novel chemical matters for metabolic enzymes, setting the stage for the next generation of drug discovery. This article aims to update on recent advances and lessons learnt on inborn errors of metabolism via the protein-centric approach, citing examples of work from my group, collaborators and co-workers that cover diverse pathways of transsulfuration, cobalamin and glycogen metabolism. Taking into consideration that many inborn errors of metabolism result in the loss of enzyme function, this presentation aims to outline three key principles that guide the design of small molecule therapy in this technically challenging field: (1) integrating structural, biochemical and cell-based data to evaluate the wide spectrum of mutation-driven enzyme defects in stability, catalysis and protein-protein interaction; (2) studying multi-domain proteins and multi-protein complexes as examples from nature, to learn how enzymes are activated by small molecules; (3) surveying different regions of the enzyme, away from its active site, that can be targeted for the design of allosteric activators and inhibitors.
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Affiliation(s)
- Wyatt W Yue
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, OX3 7DQ, UK.
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27
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Abstract
More than 950 phenylalanine hydroxylase (PAH) gene variants have been identified in people with phenylketonuria (PKU). These vary in their consequences for the residual level of PAH activity, from having little or no effect to abolishing PAH activity completely. Advances in genotyping technology and the availability of locus-specific and genotype databases have greatly expanded our understanding of the correlations between individual gene variant, residual PAH activity, tetrahydrobiopterin (BH4 ) responsiveness, and the clinical PKU phenotype. Most patients (∼76%) have compound heterozygous PAH gene variants and one mutated allele may markedly influence the activity of the second mutated allele, which in turn may influence either positively or negatively the activity of the biologically active heterotetrameric form of the PAH. While it is possible to predict the level of BH4 responsiveness (∼71%) and PKU severity (∼78%) from the nature of the underlying gene variants, these relationships remain complex and incompletely understood. A greater understanding of these relationships may increase the potential for individualized management of PKU in future. Inherited deficiencies in BH4 metabolism account for about 1%-2% of all hyperphenylalaninemias and are clinically more severe than PKU. Almost 90% of all patients are deficient in 6-pyruvoyl-tetrahydropterin synthase and dihydropteridine reductase.
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Affiliation(s)
- Nenad Blau
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany
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28
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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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29
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Meisburger SP, Taylor AB, Khan CA, Zhang S, Fitzpatrick PF, Ando N. Domain Movements upon Activation of Phenylalanine Hydroxylase Characterized by Crystallography and Chromatography-Coupled Small-Angle X-ray Scattering. J Am Chem Soc 2016; 138:6506-16. [PMID: 27145334 PMCID: PMC4896396 DOI: 10.1021/jacs.6b01563] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mammalian phenylalanine hydroxylase (PheH) is an allosteric enzyme that catalyzes the first step in the catabolism of the amino acid phenylalanine. Following allosteric activation by high phenylalanine levels, the enzyme catalyzes the pterin-dependent conversion of phenylalanine to tyrosine. Inability to control elevated phenylalanine levels in the blood leads to increased risk of mental disabilities commonly associated with the inherited metabolic disorder, phenylketonuria. Although extensively studied, structural changes associated with allosteric activation in mammalian PheH have been elusive. Here, we examine the complex allosteric mechanisms of rat PheH using X-ray crystallography, isothermal titration calorimetry (ITC), and small-angle X-ray scattering (SAXS). We describe crystal structures of the preactivated state of the PheH tetramer depicting the regulatory domains docked against the catalytic domains and preventing substrate binding. Using SAXS, we further describe the domain movements involved in allosteric activation of PheH in solution and present the first demonstration of chromatography-coupled SAXS with Evolving Factor Analysis (EFA), a powerful method for separating scattering components in a model-independent way. Together, these results support a model for allostery in PheH in which phenylalanine stabilizes the dimerization of the regulatory domains and exposes the active site for substrate binding and other structural changes needed for activity.
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Affiliation(s)
- Steve P. Meisburger
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Alexander B. Taylor
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Crystal A. Khan
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Shengnan Zhang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Paul F. Fitzpatrick
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Nozomi Ando
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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30
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Patel D, Kopec J, Fitzpatrick F, McCorvie TJ, Yue WW. Structural basis for ligand-dependent dimerization of phenylalanine hydroxylase regulatory domain. Sci Rep 2016; 6:23748. [PMID: 27049649 PMCID: PMC4822156 DOI: 10.1038/srep23748] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 03/08/2016] [Indexed: 02/01/2023] Open
Abstract
The multi-domain enzyme phenylalanine hydroxylase (PAH) catalyzes the hydroxylation of dietary I-phenylalanine (Phe) to I-tyrosine. Inherited mutations that result in PAH enzyme deficiency are the genetic cause of the autosomal recessive disorder phenylketonuria. Phe is the substrate for the PAH active site, but also an allosteric ligand that increases enzyme activity. Phe has been proposed to bind, in addition to the catalytic domain, a site at the PAH N-terminal regulatory domain (PAH-RD), to activate the enzyme via an unclear mechanism. Here we report the crystal structure of human PAH-RD bound with Phe at 1.8 Å resolution, revealing a homodimer of ACT folds with Phe bound at the dimer interface. This work delivers the structural evidence to support previous solution studies that a binding site exists in the RD for Phe, and that Phe binding results in dimerization of PAH-RD. Consistent with our structural observation, a disease-associated PAH mutant impaired in Phe binding disrupts the monomer:dimer equilibrium of PAH-RD. Our data therefore support an emerging model of PAH allosteric regulation, whereby Phe binds to PAH-RD and mediates the dimerization of regulatory modules that would bring about conformational changes to activate the enzyme.
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Affiliation(s)
- Dipali Patel
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
| | - Jolanta Kopec
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
| | - Fiona Fitzpatrick
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
| | - Thomas J McCorvie
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
| | - Wyatt W Yue
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, UK OX3 7DQ
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31
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First structure of full-length mammalian phenylalanine hydroxylase reveals the architecture of an autoinhibited tetramer. Proc Natl Acad Sci U S A 2016; 113:2394-9. [PMID: 26884182 DOI: 10.1073/pnas.1516967113] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Improved understanding of the relationship among structure, dynamics, and function for the enzyme phenylalanine hydroxylase (PAH) can lead to needed new therapies for phenylketonuria, the most common inborn error of amino acid metabolism. PAH is a multidomain homo-multimeric protein whose conformation and multimerization properties respond to allosteric activation by the substrate phenylalanine (Phe); the allosteric regulation is necessary to maintain Phe below neurotoxic levels. A recently introduced model for allosteric regulation of PAH involves major domain motions and architecturally distinct PAH tetramers [Jaffe EK, Stith L, Lawrence SH, Andrake M, Dunbrack RL, Jr (2013) Arch Biochem Biophys 530(2):73-82]. Herein, we present, to our knowledge, the first X-ray crystal structure for a full-length mammalian (rat) PAH in an autoinhibited conformation. Chromatographic isolation of a monodisperse tetrameric PAH, in the absence of Phe, facilitated determination of the 2.9 Å crystal structure. The structure of full-length PAH supersedes a composite homology model that had been used extensively to rationalize phenylketonuria genotype-phenotype relationships. Small-angle X-ray scattering (SAXS) confirms that this tetramer, which dominates in the absence of Phe, is different from a Phe-stabilized allosterically activated PAH tetramer. The lack of structural detail for activated PAH remains a barrier to complete understanding of phenylketonuria genotype-phenotype relationships. Nevertheless, the use of SAXS and X-ray crystallography together to inspect PAH structure provides, to our knowledge, the first complete view of the enzyme in a tetrameric form that was not possible with prior partial crystal structures, and facilitates interpretation of a wealth of biochemical and structural data that was hitherto impossible to evaluate.
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32
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Zhang S, Fitzpatrick PF. Identification of the Allosteric Site for Phenylalanine in Rat Phenylalanine Hydroxylase. J Biol Chem 2016; 291:7418-25. [PMID: 26823465 DOI: 10.1074/jbc.m115.709998] [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: 12/11/2015] [Indexed: 11/06/2022] Open
Abstract
Liver phenylalanine hydroxylase (PheH) is an allosteric enzyme that requires activation by phenylalanine for full activity. The location of the allosteric site for phenylalanine has not been established. NMR spectroscopy of the isolated regulatory domain (RDPheH(25-117) is the regulatory domain of PheH lacking residues 1-24) of the rat enzyme in the presence of phenylalanine is consistent with formation of a side-by-side ACT dimer. Six residues in RDPheH(25-117) were identified as being in the phenylalanine-binding site on the basis of intermolecular NOEs between unlabeled phenylalanine and isotopically labeled protein. The location of these residues is consistent with two allosteric sites per dimer, with each site containing residues from both monomers. Site-specific variants of five of the residues (E44Q, A47G, L48V, L62V, and H64N) decreased the affinity of RDPheH(25-117) for phenylalanine based on the ability to stabilize the dimer. Incorporation of the A47G, L48V, and H64N mutations into the intact protein increased the concentration of phenylalanine required for activation. The results identify the location of the allosteric site as the interface of the regulatory domain dimer formed in activated PheH.
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Affiliation(s)
- Shengnan Zhang
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
| | - Paul F Fitzpatrick
- From the Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229
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33
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Ahmad MF, Huff SE, Pink J, Alam I, Zhang A, Perry K, Harris ME, Misko T, Porwal SK, Oleinick NL, Miyagi M, Viswanathan R, Dealwis CG. Identification of Non-nucleoside Human Ribonucleotide Reductase Modulators. J Med Chem 2015; 58:9498-509. [PMID: 26488902 DOI: 10.1021/acs.jmedchem.5b00929] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ribonucleotide reductase (RR) catalyzes the rate-limiting step of dNTP synthesis and is an established cancer target. Drugs targeting RR are mainly nucleoside in nature. In this study, we sought to identify non-nucleoside small-molecule inhibitors of RR. Using virtual screening, binding affinity, inhibition, and cell toxicity, we have discovered a class of small molecules that alter the equilibrium of inactive hexamers of RR, leading to its inhibition. Several unique chemical categories, including a phthalimide derivative, show micromolar IC50s and KDs while demonstrating cytotoxicity. A crystal structure of an active phthalimide binding at the targeted interface supports the noncompetitive mode of inhibition determined by kinetic studies. Furthermore, the phthalimide shifts the equilibrium from dimer to hexamer. Together, these data identify several novel non-nucleoside inhibitors of human RR which act by stabilizing the inactive form of the enzyme.
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Affiliation(s)
- Md Faiz Ahmad
- Department of Pharmacology, School of Medicine, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Sarah E Huff
- Department of Chemistry, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - John Pink
- Case Comprehensive Cancer Center, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Intekhab Alam
- Department of Pharmacology, School of Medicine, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Andrew Zhang
- Department of Pharmacology, School of Medicine, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Kay Perry
- Northeastern-CAT at the Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Michael E Harris
- Department of Biochemistry, School of Medicine, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Tessianna Misko
- Department of Pharmacology, School of Medicine, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Suheel K Porwal
- Department of Chemistry, Dehradun Institute of Technology, University of Deharadun , Dehradun 248197, India
| | - Nancy L Oleinick
- Case Comprehensive Cancer Center, Case Western Reserve University , Cleveland, Ohio 44106, United States.,Department of Radiation Oncology, School of Medicine, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Masaru Miyagi
- Center for Proteomics and Bioinformatics, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Rajesh Viswanathan
- Department of Chemistry, Case Western Reserve University , Cleveland, Ohio 44106, United States
| | - Chris Godfrey Dealwis
- Department of Pharmacology, School of Medicine, Case Western Reserve University , Cleveland, Ohio 44106, United States.,Center for Proteomics and the Department of Chemistry, Case Western Reserve University , Cleveland, Ohio 44106, United States
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34
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Carluccio C, Fraternali F, Salvatore F, Fornili A, Zagari A. Towards the identification of the allosteric Phe-binding site in phenylalanine hydroxylase. J Biomol Struct Dyn 2015; 34:497-507. [PMID: 26479306 DOI: 10.1080/07391102.2015.1052016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The enzyme phenylalanine hydroxylase (PAH) is defective in the inherited disorder phenylketonuria. PAH, a tetrameric enzyme, is highly regulated and displays positive cooperativity for its substrate, Phe. Whether Phe binds to an allosteric site is a matter of debate, despite several studies worldwide. To address this issue, we generated a dimeric model for Phe-PAH interactions, by performing molecular docking combined with molecular dynamics simulations on human and rat wild-type sequences and also on a human G46S mutant. Our results suggest that the allosteric Phe-binding site lies at the dimeric interface between the regulatory and the catalytic domains of two adjacent subunits. The structural and dynamical features of the site were characterized in depth and described. Interestingly, our findings provide evidence for lower allosteric Phe-binding ability of the G46S mutant than the human wild-type enzyme. This also explains the disease-causing nature of this mutant.
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Affiliation(s)
- Carla Carluccio
- a CEINGE-Biotecnologie Avanzate , S.c. a r.l., Napoli , Italy
| | - Franca Fraternali
- b Randall Division of Cell and Molecular Biophysics , King's College London , London , UK
| | - Francesco Salvatore
- a CEINGE-Biotecnologie Avanzate , S.c. a r.l., Napoli , Italy.,c SDN-Istituto di Ricerca Diagnostica e Nucleare , Napoli , Italy
| | - Arianna Fornili
- b Randall Division of Cell and Molecular Biophysics , King's College London , London , UK
| | - Adriana Zagari
- a CEINGE-Biotecnologie Avanzate , S.c. a r.l., Napoli , Italy
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35
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Zhang S, Hinck AP, Fitzpatrick PF. The Amino Acid Specificity for Activation of Phenylalanine Hydroxylase Matches the Specificity for Stabilization of Regulatory Domain Dimers. Biochemistry 2015; 54:5167-74. [PMID: 26252467 PMCID: PMC4551101 DOI: 10.1021/acs.biochem.5b00616] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Liver
phenylalanine hydroxylase is allosterically activated by
phenylalanine. The structural changes that accompany activation have
not been identified, but recent studies of the effects of phenylalanine
on the isolated regulatory domain of the enzyme support a model in
which phenylalanine binding promotes regulatory domain dimerization.
Such a model predicts that compounds that stabilize the regulatory
domain dimer will also activate the enzyme. Nuclear magnetic resonance
spectroscopy and analytical ultracentrifugation were used to determine
the ability of different amino acids and phenylalanine analogues to
stabilize the regulatory domain dimer. The abilities of these compounds
to activate the enzyme were analyzed by measuring their effects on
the fluorescence change that accompanies activation and on the activity
directly. At concentrations of 10–50 mM, d-phenylalanine, l-methionine, l-norleucine, and (S)-2-amino-3-phenyl-1-propanol were able to activate the enzyme to
the same extent as 1 mM l-phenylalanine. Lower levels of
activation were seen with l-4-aminophenylalanine, l-leucine, l-isoleucine, and 3-phenylpropionate. The ability
of these compounds to stabilize the regulatory domain dimer agreed
with their ability to activate the enzyme. These results support a
model in which allosteric activation of phenylalanine hydroxylase
is linked to dimerization of regulatory domains.
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Affiliation(s)
- Shengnan Zhang
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78229, United States
| | - Andrew P Hinck
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78229, United States
| | - Paul F Fitzpatrick
- Department of Biochemistry, University of Texas Health Science Center , San Antonio, Texas 78229, United States
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36
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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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37
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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
![]()
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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38
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Lang EJM, Cross PJ, Mittelstädt G, Jameson GB, Parker EJ. Allosteric ACTion: the varied ACT domains regulating enzymes of amino-acid metabolism. Curr Opin Struct Biol 2014; 29:102-11. [PMID: 25543886 DOI: 10.1016/j.sbi.2014.10.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 10/28/2014] [Indexed: 11/29/2022]
Abstract
Allosteric regulation of enzyme activity plays important metabolic roles. Here we review the allostery of enzymes of amino-acid metabolism conferred by a discrete domain known as the ACT domain. This domain of 60-70 residues has a βαββαβ topology leading to a four-stranded β4β1β3β2 antiparallel sheet with two antiparallel helices on one face. Extensive sequence variation requires a combined sequence/structure/function analysis for identification of the ACT domain. Common features include highly varied modes of self-association of ACT domains, ligand binding at domain interfaces, and transmittal of allosteric signals through conformational changes and/or the manipulation of quaternary equilibria. A recent example illustrates the relatively facile adoption of this versatile module of allostery by gene fusion.
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Affiliation(s)
- Eric J M Lang
- Maurice Wilkins Centre, Biomolecular Interaction Centre, Department of Chemistry, University of Canterbury, Christchurch, New Zealand
| | - Penelope J Cross
- Maurice Wilkins Centre, Biomolecular Interaction Centre, Department of Chemistry, University of Canterbury, Christchurch, New Zealand
| | - Gerd Mittelstädt
- Maurice Wilkins Centre, Biomolecular Interaction Centre, Department of Chemistry, University of Canterbury, Christchurch, New Zealand
| | - Geoffrey B Jameson
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Emily J Parker
- Maurice Wilkins Centre, Biomolecular Interaction Centre, Department of Chemistry, University of Canterbury, Christchurch, New Zealand.
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39
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Zhang S, Roberts KM, Fitzpatrick PF. Phenylalanine binding is linked to dimerization of the regulatory domain of phenylalanine hydroxylase. Biochemistry 2014; 53:6625-7. [PMID: 25299136 PMCID: PMC4251497 DOI: 10.1021/bi501109s] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Analytical ultracentrifugation has
been used to analyze the oligomeric
structure of the isolated regulatory domain of phenylalanine hydroxylase.
The protein exhibits a monomer–dimer equilibrium with a dissociation
constant of ∼46 μM; this value is unaffected by the removal
of the 24 N-terminal residues or by phosphorylation of Ser16. In contrast,
phenylalanine binding (Kd = 8 μM)
stabilizes the dimer. These results suggest that dimerization of the
regulatory domain of phenylalanine hydroxylase is linked to allosteric
activation of the enzyme.
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Affiliation(s)
- Shengnan Zhang
- Department of Biochemistry, University of Texas Health Science Center at San Antonio , San Antonio, Texas 78229, United States
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40
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Huang P, López Villar E. Possible mechanism and clinical potentials of allostery. Clin Transl Med 2014; 3:18. [PMID: 25024818 PMCID: PMC4091739 DOI: 10.1186/2001-1326-3-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/16/2014] [Indexed: 11/10/2022] Open
Abstract
Allostery is involved in the dynamic regulation of biological functions in proteins. Advances in allostery research have recently drawn great interest and brought allostery closer to the clinic. The present commentary describes the mechanism by which allostery may involve in from a cell-wide view and its contribution to the discovery of new therapeutics to diseases.
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Affiliation(s)
- Peixin Huang
- Liver Cancer Institute, Pulmonary Department, Fudan University Zhongshan Hospital, Shanghai 200032, China
| | - Elena López Villar
- Department of Oncohematology of Children, Hospital Universitario Niño Jesús, Avda. Menéndez Pelayo, NO 65, 28009 Madrid, Spain
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41
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Xu XL, Grant GA. Regulation of Mycobacterium tuberculosis D-3-phosphoglycerate dehydrogenase by phosphate-modulated quaternary structure dynamics and a potential role for polyphosphate in enzyme regulation. Biochemistry 2014; 53:4239-49. [PMID: 24956108 DOI: 10.1021/bi500469d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
D-3-phosphoglycerate dehydrogenase (PGDH) catalyzes the first reaction in the "phosphorylated" pathway of l-serine biosynthesis. In Mycobacterium tuberculosis, it is a type 1 enzyme (mtPGDH) in that it contains both an ACT domain and an ASB domain in addition to a catalytic domain. The published crystal structures (Protein Data Bank entries 1YGY and 3DC2) show a tartrate molecule interacting with cationic residues at the ASB-ACT domain interfaces and a serine molecule bound at the ACT domain interface. These sites have previously been shown to be involved in the mechanism of serine and substrate inhibition of catalytic activity. This investigation has revealed a mechanism of allosteric quaternary structure dynamics in mtPGDH that is modulated by physiologically relevant molecules, phosphate and polyphosphate. In the absence of phosphate and polyphosphate, the enzyme exists in equilibrium between an inactive dimer and an active tetramer that is insensitive to inhibition of catalytic activity by L-serine. Phosphate induces a conversion to an active tetramer and octamer that are sensitive to inhibition of catalytic activity by L-serine. Small polyphosphates (pyrophosphate and triphosphate) induce a conversion to an active dimer that is insensitive to L-serine inhibition. The difference in the tendency of each respective dimer to form a tetramer as well as slightly altered elution positions on size exclusion chromatography indicates that there is likely a conformational difference between the serine sensitive and insensitive states. This appears to constitute a unique mechanism in type 1 PGDHs that may be unique in pathogenic Mycobacterium species and may provide the organisms with a unique metabolic advantage.
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Affiliation(s)
- Xiao Lan Xu
- Department of Developmental Biology and ‡Department of Medicine, Washington University School of Medicine , 660 South Euclid Avenue, Box 8103, St. Louis, Missouri 63110, United States
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42
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Complex molecular regulation of tyrosine hydroxylase. J Neural Transm (Vienna) 2014; 121:1451-81. [PMID: 24866693 DOI: 10.1007/s00702-014-1238-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/04/2014] [Indexed: 12/16/2022]
Abstract
Tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, is strictly controlled by several interrelated regulatory mechanisms. Enzyme synthesis is controlled by epigenetic factors, transcription factors, and mRNA levels. Enzyme activity is regulated by end-product feedback inhibition. Phosphorylation of the enzyme is catalyzed by several protein kinases and dephosphorylation is mediated by two protein phosphatases that establish a sensitive process for regulating enzyme activity on a minute-to-minute basis. Interactions between tyrosine hydroxylase and other proteins introduce additional layers to the already tightly controlled production of catecholamines. Tyrosine hydroxylase degradation by the ubiquitin-proteasome coupled pathway represents yet another mechanism of regulation. Here, we revisit the myriad mechanisms that regulate tyrosine hydroxylase expression and activity and highlight their physiological importance in the control of catecholamine biosynthesis.
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43
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Pharmacological chaperoning: a primer on mechanism and pharmacology. Pharmacol Res 2014; 83:10-9. [PMID: 24530489 DOI: 10.1016/j.phrs.2014.01.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 12/26/2022]
Abstract
Approximately forty percent of diseases are attributable to protein misfolding, including those for which genetic mutation produces misfolding mutants. Intriguingly, many of these mutants are not terminally misfolded since native-like folding, and subsequent trafficking to functional locations, can be induced by target-specific, small molecules variably termed pharmacological chaperones, pharmacoperones, or pharmacochaperones (PCs). PC targets include enzymes, receptors, transporters, and ion channels, revealing the breadth of proteins that can be engaged by ligand-assisted folding. The purpose of this review is to provide an integrated primer of the diverse mechanisms and pharmacology of PCs. In this regard, we examine the structural mechanisms that underlie PC rescue of misfolding mutants, including the ability of PCs to act as surrogates for defective intramolecular interactions and, at the intermolecular level, overcome oligomerization deficiencies and dominant negative effects, as well as influence the subunit stoichiometry of heteropentameric receptors. Not surprisingly, PC-mediated structural correction of misfolding mutants normalizes interactions with molecular chaperones that participate in protein quality control and forward-trafficking. A variety of small molecules have proven to be efficacious PCs and the advantages and disadvantages of employing orthostatic antagonists, active-site inhibitors, orthostatic agonists, and allosteric modulator PCs are considered. Also examined is the possibility that several therapeutic agents may have unrecognized activity as PCs, and this chaperoning activity may mediate/contribute to therapeutic action and/or account for adverse effects. Lastly, we explore evidence that pharmacological chaperoning exploits intrinsic ligand-assisted folding mechanisms. Given the widespread applicability of PC rescue of mutants associated with protein folding disorders, both in vitro and in vivo, the therapeutic potential of PCs is vast. This is most evident in the treatment of lysosomal storage disorders, cystic fibrosis, and nephrogenic diabetes insipidus, for which proof of principle in humans has been demonstrated.
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44
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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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45
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Mazzola PN, Karikas GA, Schulpis KH, Dutra-Filho CS. Antioxidant treatment strategies for hyperphenylalaninemia. Metab Brain Dis 2013; 28:541-50. [PMID: 23657560 DOI: 10.1007/s11011-013-9414-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 05/01/2013] [Indexed: 12/12/2022]
Abstract
Hyperphenylalaninemia (HPA) leads to increased oxidative stress in patients with phenylketonuria (PKU) and in animal models of PKU. Early diagnosis and immediate adherence to a phenylalanine-restricted diet prevents HPA and, consequently, severe brain damage. However, treated adolescent and adult PKU patients have difficulties complying with the diet, leading to an oscillation of phenylalanine levels and associated oxidative stress. The brain is especially susceptible to reactive species, and oxidative stress might add to the impaired cognitive function found in these patients. The restricted PKU diet has a very limited nutrient content from natural foods and almost no animal protein, which reduces the intake of important compounds. These specific compounds can act as scavengers of reactive species and can be co-factors of antioxidant enzymes. Supplementation with nutrients, vitamins, and tetrahydropterin has given quite promising results in patients and animal models. Antioxidant supplementation has been studied in HPA, however there is no consensus about its always beneficial effects. In this way, regular exercise could be a beneficial addition on antioxidant status in PKU patients. A deeper understanding of PKU molecular biochemistry, and genetics, as well as the need for improved targeted treatment options, could lead to the development of new therapeutic strategies.
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Affiliation(s)
- Priscila Nicolao Mazzola
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica. Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600 - Anexo, CEP 90035-003, Porto Alegre, RS, Brazil,
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46
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Jaffe EK. Impact of quaternary structure dynamics on allosteric drug discovery. Curr Top Med Chem 2013; 13:55-63. [PMID: 23409765 DOI: 10.2174/1568026611313010006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 11/29/2012] [Accepted: 11/30/2012] [Indexed: 11/22/2022]
Abstract
The morpheein model of allosteric regulation draws attention to proteins that can exist as an equilibrium of functionally distinct assemblies where: one subunit conformation assembles into one multimer; a different subunit conformation assembles into a different multimer; and the various multimers are in a dynamic equilibrium whose position can be modulated by ligands that bind to a multimer-specific ligand binding site. The case study of porphobilinogen synthase (PBGS) illustrates how such an equilibrium holds lessons for disease mechanisms, drug discovery, understanding drug side effects, and identifying proteins wherein drug discovery efforts might focus on quaternary structure dynamics. The morpheein model of allostery has been proposed as applicable for a wide assortment of disease-associated proteins (Selwood, T., Jaffe, E., (2012) Arch. Bioch. Biophys, 519:131-143). Herein we discuss quaternary structure dynamics aspects to drug discovery for the disease-associated putative morpheeins phenylalanine hydroxylase, HIV integrase, pyruvate kinase, and tumor necrosis factor α. Also highlighted is the quaternary structure equilibrium of transthyretin and successful drug discovery efforts focused on controlling its quaternary structure dynamics.
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Affiliation(s)
- Eileen K Jaffe
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
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47
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Cross PJ, Parker EJ. Allosteric inhibitor specificity of Thermotoga maritima 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase. FEBS Lett 2013; 587:3063-8. [PMID: 23916814 DOI: 10.1016/j.febslet.2013.07.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/22/2013] [Accepted: 07/22/2013] [Indexed: 10/26/2022]
Abstract
3-Deoxy-D-arabino-heptulosonate 7-phosphate synthase (DAH7PS) catalyses the first step of the shikimate pathway for the biosynthesis of aromatic amino acids. Allosteric regulation of Thermotoga maritima DAH7PS is mediated by L-Tyr binding to a discrete ACT regulatory domain appended to a core catalytic (β/α)8 barrel. Variants of T. maritima DAH7PS (TmaDAH7PS) were created to probe the role of key residues in inhibitor selection. Substitution Ser31Gly severely reduced inhibition by L-Tyr. In contrast both L-Tyr and L-Phe inhibited the TmaHis29Ala variant, while the variant where Ser31 and His29 were interchanged (His29Ser/Ser31His), was inhibited to a greater extent by L-Phe than L-Tyr. These studies highlight the role and importance of His29 and Ser31 for determining both inhibitory ligand selectivity and the potency of allosteric response by TmaDAH7PS.
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Affiliation(s)
- Penelope J Cross
- Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch, New Zealand
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48
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Regulation of phenylalanine hydroxylase: conformational changes upon phosphorylation detected by H/D exchange and mass spectrometry. Arch Biochem Biophys 2013; 535:115-9. [PMID: 23537590 DOI: 10.1016/j.abb.2013.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 02/20/2013] [Accepted: 03/17/2013] [Indexed: 02/06/2023]
Abstract
The enzyme phenylalanine hydroxylase catalyzes the hydroxylation of excess phenylalanine in the liver to tyrosine. The enzyme is regulated allosterically by phenylalanine and by phosphorylation of Ser16. Hydrogen/deuterium exchange monitored by mass spectrometry has been used to gain insight into any structural change upon phosphorylation. Peptides in both the catalytic and regulatory domains show increased deuterium incorporation into the phosphorylated protein. Deuterium is incorporated into fewer peptides than when the enzyme is activated by phenylalanine, and the incorporation is slower. This establishes that the conformational change upon phosphorylation of phenylalanine hydroxylase is different from and less extensive than that upon phenylalanine activation.
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