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Martinez M, Harding CO, Schwank G, Thöny B. State-of-the-art 2023 on gene therapy for phenylketonuria. J Inherit Metab Dis 2024; 47:80-92. [PMID: 37401651 PMCID: PMC10764640 DOI: 10.1002/jimd.12651] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/13/2023] [Accepted: 06/30/2023] [Indexed: 07/05/2023]
Abstract
Phenylketonuria (PKU) or hyperphenylalaninemia is considered a paradigm for an inherited (metabolic) liver defect and is, based on murine models that replicate all human pathology, an exemplar model for experimental studies on liver gene therapy. Variants in the PAH gene that lead to hyperphenylalaninemia are never fatal (although devastating if untreated), newborn screening has been available for two generations, and dietary treatment has been considered for a long time as therapeutic and satisfactory. However, significant shortcomings of contemporary dietary treatment of PKU remain. A long list of various gene therapeutic experimental approaches using the classical model for human PKU, the homozygous enu2/2 mouse, witnesses the value of this model to develop treatment for a genetic liver defect. The list of experiments for proof of principle includes recombinant viral (AdV, AAV, and LV) and non-viral (naked DNA or LNP-mRNA) vector delivery methods, combined with gene addition, genome, gene or base editing, and gene insertion or replacement. In addition, a list of current and planned clinical trials for PKU gene therapy is included. This review summarizes, compares, and evaluates the various approaches for the sake of scientific understanding and efficacy testing that may eventually pave the way for safe and efficient human application.
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Affiliation(s)
- Michael Martinez
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - Cary O. Harding
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - Gerald Schwank
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Beat Thöny
- Division of Metabolism, University Children’s Hospital Zurich and Children’s Research Centre, Zurich, Switzerland
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2
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Ajami N, Soleimani A, Jafarzadeh‐Esfehani R, Hasanpour M, Rashid Shomali R, Abbaszadegan MR. Mutational landscape of phenylketonuria in Iran. J Cell Mol Med 2023; 27:2457-2466. [PMID: 37525467 PMCID: PMC10468661 DOI: 10.1111/jcmm.17865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 06/11/2023] [Accepted: 06/28/2023] [Indexed: 08/02/2023] Open
Abstract
To date more than 1000 different variants in the PAH gene have been identified in patients with phenylketonuria (PKU). In Iran, several studies have been performed to investigate the genetics bases of the PKU in different parts of the country. In this study, we have analysed and present an update of the mutational landscape of the PAH gene as well as the population genetics and frequencies of detected variants for each cohort. Published articles on PKU mutations in Iran were identified through a comprehensive PubMed, Google Scholar, Web of Science (ISI), SCOPUS, Elsevier, Wiley Online Library and SID literature search using the terms: "phenylketonuria", "hyperphenylalaninemia", and "PKU" in combination with "Iran", "Iranian population", "mutation analysis", and "Molecular genetics". Among the literature-related to genetics of PKU, 18 studies were on the PKU mutations. According to these studies, in different populations of Iran 1497 patients were included for mutation detection that resulted in detection of 129 different mutations. Results of genetic analysis of the different cohorts of Iranian PKU patients show that the most prevalent mutation in Iran is the pathogenic splice variant c.1066-11G > A, occurring in 19.54% of alleles in the cohort. Four other common mutations were p.Arg261Gln, p.Pro281Leu, c.168 + 5G > C and p.Arg243Ter (8.18%, 6.45%, 5.88% and 3.7%, respectively). One notable feature of the studied populations is its high rate of consanguineous marriages. Considering this feature, determining the prevalent PKU mutations could be advantageous for designing screening and diagnostic panels in Iran.
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Affiliation(s)
- Naser Ajami
- Department of Medical Genetics and Molecular Medicine, School of MedicineMashhad University of Medical SciencesMashhadIran
- Medical Genetics Research Center, School of MedicineMashhad University of Medical SciencesMashhadIran
| | - Anvar Soleimani
- Department of Medical Microbiology, College of Health SciencesCihan University‐ SulaimaniyaSulaimaniyaIraq
| | - Reza Jafarzadeh‐Esfehani
- Blood Borne Infections Research Center, Academic Center for EducationCulture and Research (ACECR)‐ Khorasan RazaviMashhadIran
| | - Mojtaba Hasanpour
- Department of Biology, Faculty of SciencesUniversity of GuilanRashtIran
| | - Romina Rashid Shomali
- Reproductive Health Research Center, Department of Obstetrics and Gynecology, Alzahra HospitalGuilan University of Medical SciencesRashtIran
| | - Mohammad Reza Abbaszadegan
- Department of Medical Genetics and Molecular Medicine, School of MedicineMashhad University of Medical SciencesMashhadIran
- Immunology Research CenterMashhad University of Medical SciencesMashhadIran
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3
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Alghamdi MA, O'Donnell‐Luria A, Almontashiri NA, AlAali WY, Ali HH, Levy HL. Classical phenylketonuria presenting as maternal PKU syndrome in the offspring of an intellectually normal woman. JIMD Rep 2023; 64:312-316. [PMID: 37701331 PMCID: PMC10494492 DOI: 10.1002/jmd2.12384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/06/2023] [Accepted: 07/11/2023] [Indexed: 09/14/2023] Open
Abstract
Phenylketonuria (PKU) is an autosomal recessive inborn error of metabolism resulting from a deficiency of phenylalanine hydroxylase (PAH). If untreated by dietary restriction of phenylalanine intake, impaired postnatal cognitive development results from the neurotoxic effects of excessive phenylalanine (Phe). Signs and symptoms include severe intellectual disability and behavior problems with a high frequency of seizures and variable microcephaly. Maternal PKU syndrome refers to fetal damage resulting in congenital abnormalities when the mother has untreated PKU during pregnancy. Here, we report an intellectually normal 32-year-old female who presented with recurrent pregnancy loss and two neonatal deaths with congenital heart disease, microcephaly, intrauterine growth restriction, and respiratory distress. She was diagnosed with PKU through exome sequencing performed for carrier testing with a homozygous pathogenic variant in the PAH gene, c.169_171del, p.(Glu57del) that is associated with classical PKU. Consistent with the genetic finding, she had a markedly increased plasma phenylalanine concentration of 1642 μmol/L (normal <100). This case demonstrates that recurrent pregnancy loss due to untreated maternal PKU may present as an initial finding in otherwise unsuspected classical PKU and illustrates that extreme degrees of variable expressivity may occur in classical PKU. Moreover, this case illustrates the value of genomic sequencing of women who experience recurrent pregnancy loss or neonatal anomalies.
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Affiliation(s)
- Malak Ali Alghamdi
- Harvard Medical SchoolBostonMassachusettsUSA
- Medical Genetic Division, Pediatric DepartmentCollege of Medicine, King Saud UniversityRiyadhSaudi Arabia
- Program in Medical and Population GeneticsBroad Institute of MIT and HarvardCambridgeMassachusettsUSA
| | - Anne O'Donnell‐Luria
- Harvard Medical SchoolBostonMassachusettsUSA
- Program in Medical and Population GeneticsBroad Institute of MIT and HarvardCambridgeMassachusettsUSA
- Division of Genetics and GenomicsBoston Children's HospitalBostonMassachusettsUSA
| | - Naif A. Almontashiri
- Center for Genetics and Inherited Diseases (CGID)Taibah UniversityMadinahSaudi Arabia
| | - Wajeih Y. AlAali
- Dr. Sulaiman Al Habib Medical GroupArryan HospitalRiyadhSaudi Arabia
| | - Hebatallah H. Ali
- Research Center, College of MedicineKing Saud UniversityRiyadhSaudi Arabia
| | - Harvey L. Levy
- Harvard Medical SchoolBostonMassachusettsUSA
- Program in Medical and Population GeneticsBroad Institute of MIT and HarvardCambridgeMassachusettsUSA
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4
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Yu X, Liu F, Wei B, Li M, Lu R, Pan L. Mutation Characteristics of Phenylalanine Hydroxylase Gene in Children with Phenylketonuria in Yinchuan City. Discov Med 2023; 35:533-538. [PMID: 37553307 DOI: 10.24976/discov.med.202335177.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
BACKGROUND Phenylalanine hydroxylase deficiency (PAHD) is an autosomal recessive disorder affecting phenylalanine (Phe) metabolism caused by mutations in the phenylalanine hydroxylase (PAH) gene. It has a complex phenotype with many variants and genotypes in various populations. This study sets out to analyze the screening results of children with phenylketonuria (PKU) in Yinchuan City and characterize the mutation variants of the PAH gene. METHODS Phenylketonuria screening results were retrospectively analyzed in 398,605 neonates (207,361 males and 191,244 females) born in different maternity hospitals in Yinchuan City between January 2017 and December 2021. Screening for genetic metabolic diseases was performed with parental consent at their own expense. A comprehensive diagnosis was performed by integrating tandem mass spectrometry (MS/MS) findings with clinical presentations. High-throughput sequencing (HTS) was used to detect genetic and metabolic disease-associated genes in children with PKU who were clinically diagnosed and voluntarily tested. The identified loci were validated through Sanger sequencing and parental verification. RESULTS Among the screened newborns, 45 (11.3/100,000) PKU cases were diagnosed. In the 38 cases that underwent self-financed PAH sequencing, 56 mutations were detected in 76 chromosomes, with an overall detection rate of 73.7%. All patients harbored mutant genes, and the 56 mutations detected identified represented 14 variants, including 8 missense mutations, 2 splicing mutations, 2 nonsense mutations, and 2 silent mutations. The mutations were primarily distributed in exons 2, 3, 6, 7, 9, 11, and intron 4, with the highest frequency observed in exon 7 (25 [44.7%]), followed by exon 11 (15 [26.7%]). The most prevalent mutations were exon 7-p.R252W (10 [17.9%]) and exon 7-p.R261Q (8 [14.3%]). CONCLUSIONS The PAH gene mutations in children with PKU in Yinchuan City are predominantly concentrated in exons 6, 7, and 11, with the highest detection rates observed for p.R252W and p.R261Q mutations.
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Affiliation(s)
- Xinyou Yu
- Department of Prenatal Diagnosis Center, General Hospital of Ningxia Medical University, 750004 Yinchuan, Ningxia, China
| | - Fang Liu
- Department of Reproductive Medicine, Yinchuan Maternity and Child Health Care Hospital, 750004 Yinchuan, Ningxia, China
| | - Bo Wei
- Department of Prenatal Diagnosis Center, General Hospital of Ningxia Medical University, 750004 Yinchuan, Ningxia, China
| | - Meijuan Li
- Department of Prenatal Diagnosis Center, General Hospital of Ningxia Medical University, 750004 Yinchuan, Ningxia, China
| | - Ruiping Lu
- Department of Prenatal Diagnosis Center, General Hospital of Ningxia Medical University, 750004 Yinchuan, Ningxia, China
| | - Lihua Pan
- Department of Prenatal Diagnosis Center, General Hospital of Ningxia Medical University, 750004 Yinchuan, Ningxia, China
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Jiang L, Liu Y, Zhou Y, Xu Q, Cheng S, Yan J, Xiao Y, Han L, Wang Y, Cai W. Targeted metabolomics unravels altered phenylalanine levels in piglets receiving total parenteral nutrition. FASEB J 2023; 37:e23014. [PMID: 37261736 DOI: 10.1096/fj.202300261rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/06/2023] [Accepted: 05/19/2023] [Indexed: 06/02/2023]
Abstract
Parenteral nutrition, received by many patients with intestinal failure, can induce hepatobiliary complications, which is termed as parenteral nutrition-associated liver disease (PNALD). The spectrum of PNALD ranges from cholestasis and steatosis to fibrosis and cirrhosis. Although many factors contribute to the pathogenesis of PNALD, the underlying mechanisms remain unclear. In this study, we performed targeted metabolomics to characterize the metabolomic profile in neonatal piglets receiving total parenteral nutrition (TPN) or enteral nutrition (EN) for 1 or 2 weeks. Overall, the metabolomic signature of TPN groups differed from EN groups at both time points. Among the 20 acylcarnitines identified, a majority of them were significantly reduced in TPN groups. KEGG pathway analysis showed that phenylalanine metabolism-associated pathways were dysregulated accompanied by more progressive liver steatosis associated with TPN. Next, we evaluated phenylalanine catabolism and its association with fatty acid oxidation in piglets and rats with PNALD. We showed that the hepatic expression of phenylalanine-degrading enzyme phenylalanine hydroxylase (PAH) was reduced and systemic phenylalanine levels were increased in both animal models of PNALD. Moreover, carnitine palmitoyltransferase 1A, a central regulator of fatty acid oxidation, was downregulated and its expression was negatively correlated with phenylalanine levels in TPN-fed animals. To explore the effects of phenylalanine accumulation on lipid metabolism, we treated HepG2 cells with phenylalanine co-cultured with sodium palmitate or soybean oil emulsion to induce lipid accumulation. We found that phenylalanine treatment exacerbated lipid accumulation by inhibiting fatty acid oxidation without affecting fatty acid synthesis. In summary, our findings establish a pathogenic role of increased phenylalanine levels in driving liver steatosis, linking dysregulation of phenylalanine catabolism with lipid accumulation in the context of PNALD.
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Affiliation(s)
- Lu Jiang
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
- Shanghai Institute for Pediatric Research, Shanghai, China
| | - Yang Liu
- Department of Pediatric Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yongchang Zhou
- Shanghai Institute for Pediatric Research, Shanghai, China
| | - Qingyang Xu
- Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Siyang Cheng
- Department of Pediatric Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Junkai Yan
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
- Shanghai Institute for Pediatric Research, Shanghai, China
| | - Yongtao Xiao
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
- Shanghai Institute for Pediatric Research, Shanghai, China
| | - Lianshu Han
- Department of Pediatric Endocrinology/Genetics, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ying Wang
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Wei Cai
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
- Shanghai Institute for Pediatric Research, Shanghai, China
- Department of Pediatric Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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Wang H, Wang C, Yuan W, Chen H, Lu W, Zhang H, Chen YQ, Zhao J, Chen W. The role of phenylalanine hydroxylase in lipogenesis in the oleaginous fungus Mortierella alpina. Microbiology (Reading) 2021; 167. [PMID: 34402775 DOI: 10.1099/mic.0.001062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phenylalanine hydroxylase (PAH) catalyses the irreversible hydroxylation of phenylalanine to tyrosine, which is the rate-limiting reaction in phenylalanine metabolism in animals. A variety of polyunsaturated fatty acids can be synthesized by the lipid-producing fungus Mortierella alpina, which has a wide range of industrial applications in the production of arachidonic acid. In this study, RNA interference (RNAi) with the gene PAH was used to explore the role of phenylalanine hydroxylation in lipid biosynthesis in M. alpina. Our results indicated that PAH knockdown decreased the PAH transcript level by approximately 55% and attenuated cellular fatty acid biosynthesis. Furthermore, the level of NADPH, which is a critical reducing agent and the limiting factor in lipogenesis, was decreased in response to PAH RNAi, in addition to the downregulated transcription of other genes involved in NADPH production. Our study indicates that PAH is part of an overall enzymatic and regulatory mechanism supplying NADPH required for lipogenesis in M. alpina.
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Affiliation(s)
- Hongchao Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China
| | - Chunmei Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China
| | - Weiwei Yuan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China
| | - Wenwei Lu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, PR China.,Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, PR China
| | - Yong Q Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, PR China.,Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, PR China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, PR China.,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, PR China.,Beijing Innovation Centre of Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing 100048, PR China
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Mordhorst A, Dhandapani P, Matthes S, Mosienko V, Rothe M, Todiras M, Self J, Schunck WH, Schütz A, Bader M, Alenina N. Phenylalanine hydroxylase contributes to serotonin synthesis in mice. FASEB J 2021; 35:e21648. [PMID: 33993565 DOI: 10.1096/fj.202100366r] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/11/2021] [Accepted: 04/21/2021] [Indexed: 12/31/2022]
Abstract
Serotonin is an important signaling molecule in the periphery and in the brain. The hydroxylation of tryptophan is the first and rate-limiting step of its synthesis. In most vertebrates, two enzymes have been described to catalyze this step, tryptophan hydroxylase (TPH) 1 and 2, with expression localized to peripheral and neuronal cells, respectively. However, animals lacking both TPH isoforms still exhibit about 10% of normal serotonin levels in the blood demanding an additional source of the monoamine. In this study, we provide evidence by the gain and loss of function approaches in in vitro and in vivo systems, including stable-isotope tracing in mice, that phenylalanine hydroxylase (PAH) is a third TPH in mammals. PAH contributes to serotonin levels in the blood, and may be important as a local source of serotonin in organs in which no other TPHs are expressed, such as liver and kidney.
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Affiliation(s)
- Alexander Mordhorst
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany.,Charite - University Medicine, Berlin, Germany
| | - Priyavathi Dhandapani
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Susann Matthes
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Valentina Mosienko
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | | | - Mihail Todiras
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Nicolae Testemiţanu State University of Medicine and Pharmacy, Chișinău, Moldova
| | - Julie Self
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Wolf-Hagen Schunck
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Anja Schütz
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Michael Bader
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany.,Charite - University Medicine, Berlin, Germany.,Institute for Biology, University of Lübeck, Lübeck, Germany
| | - Natalia Alenina
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany.,Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia.,Institute of Cytology, Russian Academy of Science, St. Petersburg, Russia
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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9
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Aslan T, Yenenler-Kutlu A, Gerlevik U, Aktuğlu Zeybek AÇ, Kıykım E, Sezerman OU, Birgul Iyison N. Identifying and elucidating the roles of Y198N and Y204F mutations in the PAH enzyme through molecular dynamic simulations. J Biomol Struct Dyn 2021; 40:9018-9029. [PMID: 33970801 DOI: 10.1080/07391102.2021.1921619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phenylketonuria is an autosomal recessive disorder caused by mutations in the phenylalanine hydroxylase gene. In phenylketonuria causes various symptoms including severe mental retardation. PAH gene of a classical Phenylketonuria patient was sequenced, and two novel heterozygous mutations, p.Y198N and p.Y204F, were found. This study aimed to reveal the impacts of these variants on the structural stability of the PAH enzyme. In-silico analyses using prediction tools and molecular dynamics simulations were performed. Mutations were introduced to the wild type catalytic monomer and full length tetramer crystal structures. Variant pathogenicity analyses predicted p.Y198N to be damaging, and p.Y204F to be benign by some prediction tools and damaging by others. Simulations suggested p.Y198N mutation cause significant fluctuations in the spatial organization of two catalytic residues in the temperature accelerated MD simulations with the monomer and increased root-mean-square deviations in the tetramer structure. p.Y204F causes noticeable changes in the spatial positioning of T278 suggesting a possible segregation from the catalytic site in temperature accelerated MD simulations with the monomer. This mutation also leads to increased root-mean-square fluctuations in the regulatory domain which may lead to conformational change resulting in inhibition of dimerization and enzyme activation. Our study reports two novel mutations in the PAH gene and gives insight to their effects on the PAH activity. MD simulations did not yield conclusive results that explains the phenotype but gave plausible insight to possible effects which should be investigated further with in-silico and in-vitro studies to assess the roles of these mutations in etiology of PKU. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Tolga Aslan
- Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, Bogazici University, Istanbul, Turkey
| | - Aslı Yenenler-Kutlu
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey.,Faculty of Science and Literature, Department of Molecular Biology & Genetics, Istinye University, Istanbul, Turkey
| | - Umut Gerlevik
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Ayşe Çiğdem Aktuğlu Zeybek
- Cerrahpasa Faculty of Medicine, Divisions of Nutrition and Metabolism, Department of Pediatrics, Istanbul University, İstanbul, Turkey
| | - Ertuğrul Kıykım
- Cerrahpasa Faculty of Medicine, Divisions of Nutrition and Metabolism, Department of Pediatrics, Istanbul University, İstanbul, Turkey
| | - Osman Uğur Sezerman
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Necla Birgul Iyison
- Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, Bogazici University, Istanbul, Turkey
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10
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Odagiri S, Kabata D, Tomita S, Kudo S, Sakaguchi T, Nakano N, Yamamoto K, Shintaku H, Hamazaki T. Clinical and Genetic Characteristics of Patients with Mild Hyperphenylalaninemia Identified by Newborn Screening Program in Japan. Int J Neonatal Screen 2021; 7:ijns7010017. [PMID: 33803550 PMCID: PMC8006226 DOI: 10.3390/ijns7010017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/13/2021] [Accepted: 03/15/2021] [Indexed: 11/22/2022] Open
Abstract
Phenylketonuria (PKU) and hyperphenylalaninemia (HPA), both identified in newborn screening, are attributable to variants in PAH. Reportedly, the p.R53H(c.158G>A) variant is common in patients with HPA in East Asia. Here, we aimed to define the association between p.R53H and HPA phenotype, and study the long-term outcome of patients with HPA carrying p.R53H. We retrospectively reviewed the genotype in 370 patients detected by newborn screening, and identified the phenotype in 280 (117, HPA; 163, PKU). p.R413P(c.1238G>C) was the most frequently found (n = 117, 31.6%) variant, followed by p.R53H (n = 89, 24.1%). The odds ratio for heterozygous p.R53H to cause HPA was 48.3 (95% CI 19.410-120.004). Furthermore, we assessed the non-linear association between the phenylalanine (Phe) value and elapsed time using the follow-up data of the blood Phe levels of 73 patients with HPA carrying p.R53H. The predicted levels peaked at 161.9 μmol (95% CI 152.088-172.343) at 50-60 months of age and did not exceed 360 μmol/L during the 210-month long observation period. The findings suggest that patients with HPA, carrying p.R53H, do not need frequent Phe monitoring as against those with PKU. Our study provides convincing evidence to determine clinical management of patients detected through newborn screening in Japan.
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Affiliation(s)
- Shino Odagiri
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
| | - Daijiro Kabata
- Department of Medical Statistics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (D.K.); (S.T.)
| | - Shogo Tomita
- Department of Medical Statistics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (D.K.); (S.T.)
| | - Satoshi Kudo
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
| | - Tomoko Sakaguchi
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
| | - Noriko Nakano
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
| | - Kouji Yamamoto
- Department of Biostatistics, Yokohama City University School of Medicine, Yokohama 236-0004, Japan;
| | - Haruo Shintaku
- Donated Course “Disability Medicine and Regenerative Medicine”, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan;
| | - Takashi Hamazaki
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
- Correspondence: ; Tel.: +81-6-6645-3815
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11
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Qiang R, Wang L, He J, Xu WJ, Li W, Cai N, Wang XB, Zhang R, Zhang LP, Ma XP, Wei C, Song C, Yu W, Wang X, Li X. Development of a mutation hotspot detection kit for the phenylalanine hydroxylase gene by ARMS-PCR combined with fluorescent probe technology. Biosci Rep 2021; 41:BSR20201660. [PMID: 33564846 DOI: 10.1042/BSR20201660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 01/24/2021] [Accepted: 02/09/2021] [Indexed: 11/17/2022] Open
Abstract
To develop a screening kit for detecting mutation hotspots of the phenylalanine hydroxylase (PAH) gene. Thirteen exons of the PAH gene were sequenced in 84 cases with phenylketonuria (PKU) diagnosed during neonatal genetic and metabolic disease screening in Shaanxi province, and their mutations were analyzed. We designed and developed a screening kit to detect nine mutation sites covering more than 50% of the PAH mutations found in Shaanxi province (c.728G>A, c.1197A>T, c.331C>T, c.1068C>A, c.611A>G, c.1238G>C, c.721C>T, c.442-1G>A, and c.158G>A) by using amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) combined with fluorescent probe technology. Peripheral blood and dried blood samples from PKU families were used for clinical verification of the newly developed kit. PAH gene mutations were detected in 84 children diagnosed with PKU. A total of 159 mutant alleles were identified, consisting of 100 missense mutations, 28 shear mutations, 24 nonsense mutations, and 7 deletion mutations. Exon 7 had the highest mutation frequency (32.08%). Among them, the mutation frequency of p.R243Q was the highest, accounting for 20.13% of all mutations, followed by p.R111X, IVS4-1G>A, EX6-96A>G, and p.R413P; these five loci accounted for 47.17% (75/159) of all mutations. In addition, we identified three previously unreported PAH gene mutations (p.C334X, p.G46D, and p.G256D). Fifteen mutation sites were identified in the 47 PAH carriers identified by next-generation sequencing (NGS), which were verified by the newly developed kit, with an agreement rate of 100%. This newly developed kit based on ARMS-PCR combined with fluorescent probe technology can be used to detect common PAH gene mutations.
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12
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Tresbach RH, Sperb-Ludwig F, Ligabue-Braun R, Tonon T, de Oliveira Cardoso MT, Heredia RS, da Silva Rosa MTA, Martins BC, Poubel MO, da Silva LCS, Maillot F, Schwartz IVD. Phenylketonuria Diagnosis by Massive Parallel Sequencing and Genotype-Phenotype Association in Brazilian Patients. Genes (Basel) 2020; 12:E20. [PMID: 33375644 DOI: 10.3390/genes12010020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/04/2022] Open
Abstract
Phenylketonuria (PKU) is a common inborn error of amino acid metabolism in which the enzyme phenylalanine hydroxylase, which converts phenylalanine to tyrosine, is functionally impaired due to pathogenic variants in the PAH gene. Thirty-four Brazilian patients with a biochemical diagnosis of PKU, from 33 unrelated families, were analyzed through next-generation sequencing in the Ion Torrent PGM™ platform. Phenotype–genotype correlations were made based on the BioPKU database. Three patients required additional Sanger sequencing analyses. Twenty-six different pathogenic variants were identified. The most frequent variants were c.1315+1G>A (n = 8/66), c.473G>A (n = 6/66), and c.1162G>A (n = 6/66). One novel variant, c.524C>G (p.Pro175Arg), was found in one allele and was predicted as likely pathogenic by the American College of Medical Genetics and Genomics (ACMG) criteria. The molecular modeling of p.Pro175Arg indicated that this substitution can affect monomers binding in the PAH tetramer, which could lead to a change in the stability and activity of this enzyme. Next-generation sequencing was a fast and effective method for diagnosing PKU and is useful for patient phenotype prediction and genetic counseling.
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13
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Huang L, Yao W, Wang T, Li J, He Q, Huang F. Acetylation of Phenylalanine Hydroxylase and Tryptophan 2,3-Dioxygenase Alters Hepatic Aromatic Amino Acid Metabolism in Weaned Piglets. Metabolites 2020; 10:E146. [PMID: 32283695 DOI: 10.3390/metabo10040146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/28/2020] [Accepted: 04/02/2020] [Indexed: 11/20/2022] Open
Abstract
Weaning significantly alters hepatic aromatic amino acid (AAA) metabolism and physiological functions. However, less is known about the regulating mechanism of hepatic AAA metabolism after weaning. A total of 200 21-day-old piglets (Duroc × Landrace) were assigned randomly to the control group and the weaning group. In this study, weaning significantly decreased the concentration of phenylalanine, tryptophan, and tyrosine in piglet livers (p < 0.05). Additionally, through the detection of liver AAA metabolites and metabolic enzyme activity, it was observed that hepatic tryptophan catabolism was enhanced, while that of phenylalanine was weakened (p < 0.05). Intriguingly, acetyl-proteome profiling of liver from weaned piglets showed that weaning exacerbated the acetylation of phenylalanine hydroxylase (PAH) and the deacetylation of tryptophan 2,3-dioxygenase (TDO). Analysis of PAH and TDO acetylation in Chang liver cells showed that acetylation decreased the PAH activity, while deacetylation increased the TDO activity (p < 0.05). Furthermore, metabolites of AAAs and the acetylation statuses of PAH and TDO in primary hepatocytes from weaned piglets were consistent with the results in vivo. These findings indicated that weaning altered the PAH and TDO activity by affecting the acetylation state of the enzyme in piglets’’ livers. Lysine acetylation may be a potential regulatory mechanism for AAA metabolism in response to weaning.
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14
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Jafarzadeh-Esfehani R, Vojdani S, Hashemian S, Mirinezhad M, Pourafshar M, Forouzanfar N, Zargari S, Jaripour ME, Sadr-Nabavi A. Genetic variants of the phenylalanine hydroxylase gene in patients with phenylketonuria in the northeast of Iran. J Pediatr Endocrinol Metab 2020; 33:355-359. [PMID: 32069237 DOI: 10.1515/jpem-2019-0351] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/06/2020] [Indexed: 11/15/2022]
Abstract
Background Phenylketonuria (PKU) is a common metabolic disorder with great burden if left untreated or undiagnosed. Genetic variations in the phenylalanine hydroxylase (PAH) gene may be widely varied across different regions of a country. By knowing the most common mutations, diagnostic work-ups will be offered sooner and with lower costs for patients. The present study defines the most common genetic variations in the PAH gene in Khorasan province of Iran. Methods The present cross-sectional study took place in Khorasan province of Iran within a 6-year period starting from 2012 to 2018. Every patient who had been referred as suspicious PKU cases or referred for prenatal diagnosis was included in the present study. Results A total number of 122 individuals with a mean age of 26.22 years were enrolled in the present study. The most frequent genetic variations in the PAH gene were c.1066-11G > A and c.143 T > C. Exon 7 carried the most genetic variations compared to any single exon. Also, three patients had compound heterozygous status for c.727 C > T/c.1066-11 G > A in exon 7 and 11 of the PAH gene. Conclusions Mutations in the PAH gene are widely varied among different populations, and our results confirmed this fact. Determination of the most prevalent mutations and polymorphisms in each region will reduce the time and cost of diagnosing such preventable diseases and will therefore reduce the disease burden.
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Affiliation(s)
- Reza Jafarzadeh-Esfehani
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Samaneh Vojdani
- Department of Medical Genetics, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Somayyeh Hashemian
- Department of Pediatric Diseases, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammadreza Mirinezhad
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Narjes Forouzanfar
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Selma Zargari
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Ariane Sadr-Nabavi
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Azadi Square, Mashhad, Iran.,Academic Center for Education, Culture and Research (ACECR)-Khorasan Razavi, Mashhad, Iran, Phone: 09155570305, 05138827046
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15
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Luo H, Yang L, Kim SH, Wulff T, Feist AM, Herrgard M, Palsson BØ. Directed Metabolic Pathway Evolution Enables Functional Pterin-Dependent Aromatic-Amino-Acid Hydroxylation in Escherichia coli. ACS Synth Biol 2020; 9:494-499. [PMID: 32149495 DOI: 10.1021/acssynbio.9b00488] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tetrahydrobiopterin-dependent hydroxylation of aromatic amino acids is the first step in the biosynthesis of many neuroactive compounds in humans. A fundamental challenge in building these pathways in Escherichia coli is the provision of the non-native hydroxylase cofactor, tetrahydrobiopterin. To solve this, we designed a genetic selection that relies on the tyrosine synthesis activity of phenylalanine hydroxylase. Using adaptive laboratory evolution, we demonstrate the use of this selection to discover: (1) a minimum set of heterologous enzymes and a host folE (T198I) mutation for achieving this type of hydroxylation chemistry in whole cells, (2) functional complementation of tetrahydrobiopterin by indigenous cofactors, and (3) a tryptophan hydroxylase mutation for improving protein abundance. Thus, the goal of having functional aromatic-amino-acid hydroxylation in E. coli was achieved through directed metabolic pathway evolution.
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Affiliation(s)
- Hao Luo
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Lei Yang
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Se Hyeuk Kim
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Tune Wulff
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Adam M Feist
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby 2800, Denmark
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States of America
| | - Markus Herrgard
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Bernhard Ø Palsson
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kongens Lyngby 2800, Denmark
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States of America
- Department of Pediatrics, University of California, San Diego, La Jolla, California 92093, United States of America
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16
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Richards DY, Winn SR, Dudley S, Nygaard S, Mighell TL, Grompe M, Harding CO. AAV-Mediated CRISPR/Cas9 Gene Editing in Murine Phenylketonuria. Mol Ther Methods Clin Dev 2019; 17:234-245. [PMID: 31970201 PMCID: PMC6962637 DOI: 10.1016/j.omtm.2019.12.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 12/10/2019] [Indexed: 12/12/2022]
Abstract
Phenylketonuria (PKU) due to recessively inherited phenylalanine hydroxylase (PAH) deficiency results in hyperphenylalaninemia, which is toxic to the central nervous system. Restriction of dietary phenylalanine intake remains the standard of PKU care and prevents the major neurologic manifestations of the disease, yet shortcomings of dietary therapy remain, including poor adherence to a difficult and unpalatable diet, an increased incidence of neuropsychiatric illness, and imperfect neurocognitive outcomes. Gene therapy for PKU is a promising novel approach to promote lifelong neurological protection while allowing unrestricted dietary phenylalanine intake. In this study, liver-tropic recombinant AAV2/8 vectors were used to deliver CRISPR/Cas9 machinery and facilitate correction of the Pah enu2 allele by homologous recombination. Additionally, a non-homologous end joining (NHEJ) inhibitor, vanillin, was co-administered with the viral drug to promote homology-directed repair (HDR) with the AAV-provided repair template. This combinatorial drug administration allowed for lifelong, permanent correction of the Pah enu2 allele in a portion of treated hepatocytes of mice with PKU, yielding partial restoration of liver PAH activity, substantial reduction of blood phenylalanine, and prevention of maternal PKU effects during breeding. This work reveals that CRISPR/Cas9 gene editing is a promising tool for permanent PKU gene editing.
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Affiliation(s)
- Daelyn Y Richards
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Shelley R Winn
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Sandra Dudley
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Sean Nygaard
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Taylor L Mighell
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Markus Grompe
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Cary O Harding
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
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17
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Sarkar A, Mukundan N, Sowndarya S, Dubey VK, Babu R, Lakshmanan V, Rangiah K, Panicker MM, Palakodeti D, Subramanian SP, Subramanian R. Serotonin is essential for eye regeneration in planaria Schmidtea mediterranea. FEBS Lett 2019; 593:3198-3209. [PMID: 31529697 DOI: 10.1002/1873-3468.13607] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/23/2019] [Accepted: 09/06/2019] [Indexed: 12/31/2022]
Abstract
Planaria is an ideal system to study factors involved in regeneration and tissue homeostasis. Little is known about the role of metabolites and small molecules in stem cell maintenance and lineage specification in planarians. Using liquid chromatography and mass spectrometry (LC-MS)-based quantitative metabolomics, we determined the relative levels of metabolites in stem cells, progenitors, and differentiated cells of the planarian Schmidtea mediterranea. Tryptophan and its metabolic product serotonin are significantly enriched in stem cells and progenitor population. Serotonin biosynthesis in these cells is brought about by a noncanonical enzyme, phenylalanine hydroxylase. Knockdown of Smed-pah leads to complete disappearance of eyes in regenerating planaria, while exogenous supply of serotonin and its precursor rescues the eyeless phenotype. Our results demonstrate a key role for serotonin in eye regeneration.
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Affiliation(s)
- Arunabha Sarkar
- National Centre for Biological Sciences (NCBS), Bangalore, Karnataka, India
| | - Namita Mukundan
- Institute for Stem Cell Science and Regenerative Medicine (InStem), Bangalore, Karnataka, India.,Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India
| | - Sai Sowndarya
- Institute for Stem Cell Science and Regenerative Medicine (InStem), Bangalore, Karnataka, India
| | - Vinay Kumar Dubey
- Institute for Stem Cell Science and Regenerative Medicine (InStem), Bangalore, Karnataka, India.,Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India
| | - Rosana Babu
- Institute for Stem Cell Science and Regenerative Medicine (InStem), Bangalore, Karnataka, India
| | - Vairavan Lakshmanan
- Institute for Stem Cell Science and Regenerative Medicine (InStem), Bangalore, Karnataka, India
| | - Kannan Rangiah
- Central Food Technology Research Institute, Mysore, Karnataka, India
| | | | - Dasaradhi Palakodeti
- Institute for Stem Cell Science and Regenerative Medicine (InStem), Bangalore, Karnataka, India
| | | | - Ramaswamy Subramanian
- Institute for Stem Cell Science and Regenerative Medicine (InStem), Bangalore, Karnataka, India
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18
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Zastrow DB, Baudet H, Shen W, Thomas A, Si Y, Weaver MA, Lager AM, Liu J, Mangels R, Dwight SS, Wright MW, Dobrowolski SF, Eilbeck K, Enns GM, Feigenbaum A, Lichter-Konecki U, Lyon E, Pasquali M, Watson M, Blau N, Steiner RD, Craigen WJ, Mao R. Unique aspects of sequence variant interpretation for inborn errors of metabolism (IEM): The ClinGen IEM Working Group and the Phenylalanine Hydroxylase Gene. Hum Mutat 2019; 39:1569-1580. [PMID: 30311390 DOI: 10.1002/humu.23649] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/28/2018] [Accepted: 09/06/2018] [Indexed: 11/09/2022]
Abstract
The ClinGen Inborn Errors of Metabolism Working Group was tasked with creating a comprehensive, standardized knowledge base of genes and variants for metabolic diseases. Phenylalanine hydroxylase (PAH) deficiency was chosen to pilot development of the Working Group's standards and guidelines. A PAH variant curation expert panel (VCEP) was created to facilitate this process. Following ACMG-AMP variant interpretation guidelines, we present the development of these standards in the context of PAH variant curation and interpretation. Existing ACMG-AMP rules were adjusted based on disease (6) or strength (5) or both (2). Disease adjustments include allele frequency thresholds, functional assay thresholds, and phenotype-specific guidelines. Our validation of PAH-specific variant interpretation guidelines is presented using 85 variants. The PAH VCEP interpretations were concordant with existing interpretations in ClinVar for 69 variants (81%). Development of biocurator tools and standards are also described. Using the PAH-specific ACMG-AMP guidelines, 714 PAH variants have been curated and will be submitted to ClinVar. We also discuss strategies and challenges in applying ACMG-AMP guidelines to autosomal recessive metabolic disease, and the curation of variants in these genes.
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Affiliation(s)
- Diane B Zastrow
- Palo Alto Medical Foundation, Palo Alto, California.,Stanford University, Stanford, California
| | - Heather Baudet
- University of North Carolina, Chapel Hill, North Carolina
| | - Wei Shen
- ARUP Laboratories, Salt Lake City, Utah.,University of Utah, Salt Lake City, Utah
| | - Amanda Thomas
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York
| | - Yue Si
- GeneDx, Gaithersburg, Maryland
| | - Meredith A Weaver
- American College of Medical Genetics and Genomics, Bethesda, Maryland
| | - Angela M Lager
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Jixia Liu
- Marshfield Clinic Research Institute, Marshfield, Wisconsin
| | | | | | | | | | | | | | - Annette Feigenbaum
- Rady Children's Hospital and University of California, San Diego, California
| | - Uta Lichter-Konecki
- Children's Hospital of Pittsburg of UPMC, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Elaine Lyon
- ARUP Laboratories, Salt Lake City, Utah.,University of Utah, Salt Lake City, Utah
| | - Marzia Pasquali
- ARUP Laboratories, Salt Lake City, Utah.,University of Utah, Salt Lake City, Utah
| | - Michael Watson
- American College of Medical Genetics and Genomics, Bethesda, Maryland
| | - Nenad Blau
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany
| | - Robert D Steiner
- Marshfield Clinic Research Institute, Marshfield, Wisconsin.,University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | | | - Rong Mao
- ARUP Laboratories, Salt Lake City, Utah.,University of Utah, Salt Lake City, Utah
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19
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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20
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Abstract
1. Consistent differences in the proportion of an orally administered dose of S-carboxymethyl-l-cysteine subsequently excreted in the urine as S-oxide metabolites were reported 40 years ago. This observation suggested the existence of inter-individual variation in the ability to undertake the enzymatic S-oxygenation of this compound. Pedigree studies and investigations employing twin pairs indicated a genetically controlled phenomenon overlaid with environmental influences. It was reproducible and not related to gender or age.2. Studies undertaken in several healthy volunteer cohorts always provided similar results that were not significantly different when statistically analysed. However, when compared to these healthy populations, a preponderance of subjects exhibiting the characteristic of poor sulfoxidation of S-carboxymethyl-l-cysteine was found within groups of patients suffering from various disease conditions. The most striking of these associations were witnessed amongst subjects diagnosed with neurodegenerative disorders; although, underlying mechanisms were unknown.3. Exhaustive investigation has identified the enzyme responsible for this S-oxygenation reaction as the tetrahydrobiopterin-dependent aromatic amino acid hydroxylase, phenylalanine 4-monooxygenase classically assigned the sole function of converting phenylalanine to tyrosine. The underlying principle is discussed that enzymes traditionally associated solely with intermediary metabolism may have as yet unrecognised alternative roles in protecting the organism from potential toxic assault.
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Affiliation(s)
- Stephen C Mitchell
- Section of Computational and Systems Medicine, Faculty of Medicine, Imperial College London, London, UK
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21
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Pecimonova M, Kluckova D, Csicsay F, Reblova K, Krahulec J, Procházkova D, Skultety L, Kadasi L, Soltysova A. Structural and Functional Impact of Seven Missense Variants of Phenylalanine Hydroxylase. Genes (Basel) 2019; 10:E459. [PMID: 31208052 PMCID: PMC6628251 DOI: 10.3390/genes10060459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 11/17/2022] Open
Abstract
The molecular genetics of well-characterized inherited diseases, such as phenylketonuria (PKU) and hyperphenylalaninemia (HPA) predominantly caused by mutations in the phenylalanine hydroxylase (PAH) gene, is often complicated by the identification of many novel variants, often with no obvious impact on the associated disorder. To date, more than 1100 PAH variants have been identified of which a substantial portion have unknown clinical significance. In this work, we study the functionality of seven yet uncharacterized PAH missense variants p.Asn167Tyr, p.Thr200Asn, p.Asp229Gly, p.Gly239Ala, p.Phe263Ser, p.Ala342Pro, and p.Ile406Met first identified in the Czech PKU/HPA patients. From all tested variants, three of them, namely p.Asn167Tyr, p.Thr200Asn, and p.Ile406Met, exerted residual enzymatic activity in vitro similar to wild type (WT) PAH, however, when expressed in HepG2 cells, their protein level reached a maximum of 72.1% ± 4.9%, 11.2% ± 4.2%, and 36.6% ± 7.3% compared to WT PAH, respectively. Remaining variants were null with no enzyme activity and decreased protein levels in HepG2 cells. The chaperone-like effect of applied BH4 precursor increased protein level significantly for p.Asn167Tyr, p.Asp229Gly, p.Ala342Pro, and p.Ile406Met. Taken together, our results of functional characterization in combination with in silico prediction suggest that while p.Asn167Tyr, p.Thr200Asn, and p.Ile406Met PAH variants have a mild impact on the protein, p.Asp229Gly, p.Gly239Ala, p.Phe263Ser, and p.Ala342Pro severely affect protein structure and function.
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Affiliation(s)
- Martina Pecimonova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Daniela Kluckova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Frantisek Csicsay
- Insitute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Kamila Reblova
- Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic.
| | - Jan Krahulec
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Dagmar Procházkova
- Department of Pediatrics, Medical Faculty of Masaryk University and University Hospital Brno, Černopolní 9, 625 00 Brno, Czech Republic.
| | - Ludovit Skultety
- Insitute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Ludevit Kadasi
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
- Institute for Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Andrea Soltysova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
- Institute for Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
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22
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Vieira Neto E, Laranjeira F, Quelhas D, Ribeiro I, Seabra A, Mineiro N, Carvalho LM, Lacerda L, Ribeiro MG. Genotype-phenotype correlations and BH 4 estimated responsiveness in patients with phenylketonuria from Rio de Janeiro, Southeast Brazil. Mol Genet Genomic Med 2019; 7:e610. [PMID: 30829006 PMCID: PMC6503030 DOI: 10.1002/mgg3.610] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/15/2019] [Accepted: 01/24/2019] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Genetic heterogeneity and compound heterozygosis give rise to a continuous spectrum of phenylalanine hydroxylase deficiency and metabolic phenotypes in phenylketonuria (PKU). The most used parameters for evaluating phenotype in PKU are pretreatment phenylalanine (Phe) levels, tolerance for dietary Phe, and Phe overloading test. Phenotype can vary from a "classic" (severe) form to mild hyperphenylalaninemia, which does not require dietary treatment. A subset of patients is responsive to treatment by the cofactor tetrahydrobiopterin (BH4 ). Genotypes of PKU patients from Rio de Janeiro, Brazil, were compared to predicted and observed phenotypes. Genotype-based estimations of responsiveness to BH4 were also conducted. METHODS Phenotype was defined by pretreatment Phe levels. A standard prediction system based on arbitrary assigned values was employed to measure genotype-phenotype concordance. Patients were also estimated as BH4 -responders according to the responsiveness previously reported for their mutations and genotypes. RESULTS A 48.3% concordance rate between genotype-predicted and observed phenotypes was found. When the predicted phenotypes included those reported at the BIOPKU database, the concordance rate reached 77%. A total of 18 genotypes from 30 patients (29.4%) were estimated as of potential or probable BH4 responsiveness. Inconsistencies were observed in genotypic combinations including the common "moderate" mutations p.R261Q, p.V388M, and p.I65T and the mild mutations p.L48S, p.R68S, and p.L249F. CONCLUSION The high discordance rate between genotype-predicted and observed metabolic phenotypes in this study seems to be due partially to the high frequency of the so-called "moderate" common mutations, p.R261Q, p.V388M, and p.I65T, which are reported to be associated to erratic or more severe than expected metabolic phenotypes. Although our results of BH4 estimated responsiveness must be regarded as tentative, it should be emphasized that genotyping and genotype-phenotype association studies are important in selecting patients to be offered a BH4 overload test, especially in low-resource settings like Brazil.
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Affiliation(s)
- Eduardo Vieira Neto
- Agência Nacional de Saúde SuplementarGerência de Monitoramento AssistencialRio de JaneiroBrazil
- Serviço de Genética MédicaInstituto de Puericultura e Pediatria Martagão GesteiraUniversidade Federal do Rio de JaneiroRio de JaneiroBrazil
| | - Francisco Laranjeira
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Dulce Quelhas
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
- Unidade Multidisciplinar de Investigação BiomédicaUniversidade do PortoPortoPortugal
| | - Isaura Ribeiro
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
- Unidade Multidisciplinar de Investigação BiomédicaUniversidade do PortoPortoPortugal
| | - Alexandre Seabra
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
- Instituto de Ciências Biomédicas Abel SalazarUniversidade do PortoPortoPortugal
| | - Nicole Mineiro
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Lilian M. Carvalho
- Serviço de MetabologiaInstituto Estadual de Diabetes e Endocrinologia Luiz CapriglioneRio de JaneiroBrazil
| | - Lúcia Lacerda
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Márcia G. Ribeiro
- Serviço de Genética MédicaInstituto de Puericultura e Pediatria Martagão GesteiraUniversidade Federal do Rio de JaneiroRio de JaneiroBrazil
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23
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Rawlings L, Turton L, Mitchell SC, Steventon GB. Drug S-oxidation and phenylalanine hydroxylase: a biomarker for neurodegenerative susceptibility in Parkinson's disease and amyotrophic lateral sclerosis. Drug Metab Pers Ther 2019; 34:/j/dmdi.ahead-of-print/dmpt-2018-0038/dmpt-2018-0038.xml. [PMID: 30939113 DOI: 10.1515/dmpt-2018-0038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/11/2019] [Indexed: 06/09/2023]
Abstract
Background The S-oxidation of S-carboxymethyl-L-cysteine has been reported previously to be a biomarker of disease susceptibility in Parkinson's disease and amyotrophic lateral sclerosis. In the present investigation, the original observations have been extended and confirmed. Methods Meta-analysis of previously published investigations into the S-oxidation polymorphism together with new subject data was evaluated. Results The incidence of the poor metaboliser phenotype (no urinary recovery of S-oxide metabolites) was found to be 3%-7% within healthy and non-neurological disease populations, whereas 38% of the Parkinson's disease subjects and 39% of the amyotrophic lateral sclerosis group were phenotyped as poor metabolisers. The consequent odds risk ratio of developing Parkinson's disease was calculated to be 33.8 [95% confidence interval (CI), 13.3-86.1] and for amyotrophic lateral sclerosis was 35.2 (95% CI, 13.0-85.1). Conclusions The possible involvement of the enzyme responsible for this S-oxidation biotransformation reaction, phenylalanine hydroxylase, should be further investigated to elucidate its potential role in the mechanism(s) of toxicity in susceptible individuals displaying these diseases. The "Janus hypothesis," possibly explaining why phenylalanine hydroxylase is a biomarker of neurodegenerative disease susceptibility, together with the general theme that this concept may apply to many other hitherto unsuspected enzyme systems, is presented.
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Affiliation(s)
| | - Laura Turton
- Syneos Health, Thames House, Maidenhead, Berkshire, UK
| | - Stephen C Mitchell
- Section of Computational and Systems Medicine, Faculty of Medicine, Imperial College London, South Kensington, London, UK
| | - Glyn B Steventon
- ADMET Solutions Ltd., Ivar Gardens, Lychpit, Basingstoke, Hampshire RG24 8YD, UK, Phone: +44 (0)7786907053
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24
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Khan CA, Meisburger SP, Ando N, Fitzpatrick PF. The phenylketonuria-associated substitution R68S converts phenylalanine hydroxylase to a constitutively active enzyme but reduces its stability. J Biol Chem 2019; 294:4359-4367. [PMID: 30674554 DOI: 10.1074/jbc.ra118.006477] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/15/2019] [Indexed: 11/06/2022] Open
Abstract
The naturally occurring R68S substitution of phenylalanine hydroxylase (PheH) causes phenylketonuria (PKU). However, the molecular basis for how the R68S variant leads to PKU remains unclear. Kinetic characterization of R68S PheH establishes that the enzyme is fully active in the absence of allosteric binding of phenylalanine, in contrast to the WT enzyme. Analytical ultracentrifugation establishes that the isolated regulatory domain of R68S PheH is predominantly monomeric in the absence of phenylalanine and dimerizes in its presence, similar to the regulatory domain of the WT enzyme. Fluorescence and small-angle X-ray scattering analyses establish that the overall conformation of the resting form of R68S PheH is different from that of the WT enzyme. The data are consistent with the substitution disrupting the interface between the catalytic and regulatory domains of the enzyme, shifting the equilibrium between the resting and activated forms ∼200-fold, so that the resting form of R68S PheH is ∼70% in the activated conformation. However, R68S PheH loses activity 2 orders of magnitude more rapidly than the WT enzyme at 37 °C and is significantly more sensitive to proteolysis. We propose that, even though this substitution converts the enzyme to a constitutively active enzyme, it results in PKU because of the decrease in protein stability.
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Affiliation(s)
- Crystal A Khan
- From the Department of Biochemistry and Structural Biology, UT Health San Antonio, San Antonio, Texas 78229 and
| | - Steve P Meisburger
- the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Nozomi Ando
- the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Paul F Fitzpatrick
- From the Department of Biochemistry and Structural Biology, UT Health San Antonio, San Antonio, Texas 78229 and
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25
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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26
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CHEN T, ZHAO Z, JIANG P, SHU Q. [Research progress on phenotype and genotype of hyperphenylalaninemia]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2018; 47:219-226. [PMID: 30226320 PMCID: PMC10393690 DOI: 10.3785/j.issn.1008-9292.2018.06.01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 04/24/2018] [Indexed: 06/08/2023]
Abstract
Hyperphenylalaninemia(HPA), an autosomal recessive disease, is the most common inborn error of amino acid metabolism, caused by the deficiency of phenylalanine hydroxylase(PAH) or tetrahydrobiopterin(BH4) which induced by mutations of genes. The accumulation of the clinical database and genetic information will enhance the development of novel personalized medicine and to provide more accurate and timely diagnostic and therapeutic approaches for HPA. This paper summarizes the correlations between HPA metabolism and PAH, BH4, pathogenic genes and their distributions in HPA, as well as the phenotypes and genotypes of HPA, so as to provide reference for personalized medicine for HPA.
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Affiliation(s)
| | | | | | - Qiang SHU
- 舒强(1965-), 男, 博士, 主任医师, 教授, 博士生导师, 主要从事出生缺陷综合防治研究; E-mail:
;
https://orcid.org/0000-0002-4106-6255
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27
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Ye S, Zhou L, Zhou Z. [Thermal stability improvement for phenylalanine hydroxylase by site-directed mutagenesis]. Sheng Wu Gong Cheng Xue Bao 2018; 32:1243-1254. [PMID: 29022325 DOI: 10.13345/j.cjb.160022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In proteins of thermophilic bacteria, Gly is tend to be replaced by Ala and Lys is tend to be replaced by Arg to adapt the high temperature. In order to improve the thermal stability of phenylalanine hydroxylase (PAH) from Chromobacterium violaceum, all the Gly on PAH were mutated to Ala and Lys to Arg. Positive mutant enzymes with improved thermal stability were selected, followed by combined mutation and characterization. The results revealed that half-lives of K94R and G221A mutants at 50 °C were 26.2 min and 16.8 min, which were increased by 1.9-times and 0.9-times than the parent enzyme (9.0 min). The residual activity of K94R/G221A mutant was improved to 65.6% after keeping at 50 °C for 1 h, which was 6.6 time higher than the parent enzyme (8.6%). Circular dichroism (CD) spectroscopy revealed that Tm values of the parent enzyme, K94R, G221A and K94R/G221A were 51.5 ℃, 53.8 ℃, 53.1 ℃ and 54.8 ℃, respectively. According to the protein structure simulation, the two mutations were located on flexible loop. In the K94R mutant, the mutated Arg94 on the surface of the enzyme formed an extra hydrogen bond with Ile95, which stabilized the located loop. In the G221A mutant, the mutated Ala221 formed hydrophobic interaction with Leu281, which could stabilize both the loop and flexible area of the C-terminus of G221A. The results not only provided a reference for protein modification on thermal stability, but also laid the foundation for application of phenylalanine hydroxylase in the field of functional foods.
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Affiliation(s)
- Shuangshuang Ye
- School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Li Zhou
- School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Zhemin Zhou
- School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
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28
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Abstract
RATIONALE Phenylketonuria (PKU) is a metabolic disorder, which manifests a progressive irreversible neurological impairment during infancy and childhood. Hyperhomocysteinemia also showed that it might be involved in pathophysiology of many neuropsychiatric disorders. The late-onset clinical manifestations of these 2 diseases have not been reported elsewhere. We speculated that the late-onset PKU is caused by 2 kinds of metabolic dysfunction synergistically, especially a short period of irregular diet directly caused clinical symptoms. PATIENT CONCERNS A 21-year old Asian male patient demonstrated subacute leukodystrophy and visual-spatial disorders of late onset in adulthood. DIAGNOSES Phenylketonuria combined with homocysteinmia, who presented with heterozygous mutations in gene encoding PAH p.G247R (c.739G>C) and p.Y204C (c.611A>G), along with homozygous mutation of gene encoding MTHFR c.677C>T. INTERVENTIONS The patient was treated with cobalamine (500 μg/day), vitamin B6 (30 mg/day), folate (5 mg/day) and encouraged to follow a protein-restricted diet. OUTCOMES Visual disorientation and cognitive function showed improvement. Head MR showed similar resolution with the original lesion. Serum homocysteine and folate analysis were normal with decreased phenylalanine level. LESSONS This case suggests that neurological involvement of progressive nervous system dysfunction could be caused by more than one kind of inherited metabolic disturbances, and each one can induce or deteriorate the manifestations of another metabolic disorders.
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Affiliation(s)
- Chunchen Wang
- Department of Neurology & Acupuncture and Moxibustion Centre, Beijing Hospital of Traditional Chinese Medicine Affiliated to Capital Medical University, Beijing
| | - Jieying Li
- Department of Neurology, The Second People's Hospital of Guiyang, Guiyang, Guizhou, China
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29
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Zamanfar D, Jalali H, Mahdavi MR, Maadanisani M, Zaeri H, Asadpoor E. Investigation of Five Common Mutations on Phenylalanine Hydroxylase Gene of Phenylketonuria Patients from Two Provinces in North of Iran. Int J Prev Med 2017; 8:89. [PMID: 29184640 PMCID: PMC5686925 DOI: 10.4103/ijpvm.ijpvm_378_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 09/09/2017] [Indexed: 11/06/2022] Open
Abstract
Background: There are more than 500 different mutations on phenylalanine hydroxylase (PAH) gene that is responsible for phenylketonuria (PKU) diseases and the spectrum of these mutations is varied in different populations. The main clinical manifestation of untreated patients is severe mental retardation. The PAH gene, that is 90 kb long, is consisted of 13 exons and 12 introns. The aim of the present study was to identify the frequency of five common mutations on PAH gene among patients with PKU in Mazandaran and Golestan provinces including c.1066-11G>A, p. R261Q, p. R252W, p. R261X, and c.1200 + 1G>C. Methods: Forty unrelated PKU patients, that 22 of them, were from Mazandaran and 18 of them from Golestan provinces were enrolled in the study. Genomic DNA was extracted from leukocytes using Qiagen DNA extraction kit and polymerase chain reaction - restriction fragment length polymorphism method was applied to detect five common mutations. Results: Three out of the 5 investigate mutations were identified among the patients. The c.1066-11G>A mutation has the highest frequency (27.5%) among the patients and the frequency of p. R261Q and p. R261X mutations were 3.75 and 1.25%, respectively. In Golestan province, only c.1066-11G>A mutation was observed in investigated alleles. Conclusions: The high frequency of c.1066-11G>A mutation in Golestan province may be related to genetic drift, founder effect, and consanguinity.
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Affiliation(s)
- Daniel Zamanfar
- Diabetes Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Hossein Jalali
- Students research committee, Thalassemia Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mohammad Reza Mahdavi
- Students research committee, Thalassemia Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Morteza Maadanisani
- Diabetes Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Hossein Zaeri
- Neonatal and Children Health Research Center, Geolstan University of Medical Sciences, Gorgan, Iran
| | - Eynollah Asadpoor
- Central Health Center, Mazandaran University of Medical Sciences, Sari, Iran
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30
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Leandro J, Stokka AJ, Teigen K, Andersen OA, Flatmark T. Substituting Tyr 138 in the active site loop of human phenylalanine hydroxylase affects catalysis and substrate activation. FEBS Open Bio 2017; 7:1026-1036. [PMID: 28680815 PMCID: PMC5494296 DOI: 10.1002/2211-5463.12243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 04/27/2017] [Accepted: 05/10/2017] [Indexed: 11/22/2022] Open
Abstract
Mammalian phenylalanine hydroxylase (PAH) is a key enzyme in l‐phenylalanine (l‐Phe) metabolism and is active as a homotetramer. Biochemical and biophysical work has demonstrated that it cycles between two states with a variably low and a high activity, and that the substrate l‐Phe is the key player in this transition. X‐ray structures of the catalytic domain have shown mobility of a partially intrinsically disordered Tyr138‐loop to the active site in the presence of l‐Phe. The mechanism by which the loop dynamics are coupled to substrate binding at the active site in tetrameric PAH is not fully understood. We have here conducted functional studies of four Tyr138 point mutants. A high linear correlation (r2 = 0.99) was observed between their effects on the catalytic efficiency of the catalytic domain dimers and the corresponding effect on the catalytic efficiency of substrate‐activated full‐length tetramers. In the tetramers, a correlation (r2 = 0.96) was also observed between the increase in catalytic efficiency (activation) and the global conformational change (surface plasmon resonance signal response) at the same l‐Phe concentration. The new data support a similar functional importance of the Tyr138‐loop in the catalytic domain and the full‐length enzyme homotetramer.
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Affiliation(s)
- João Leandro
- Department of Biomedicine University of Bergen Norway.,Metabolism and Genetics Group Research Institute for Medicines (iMed.ULisboa) Faculty of Pharmacy University of Lisbon Portugal.,Present address: Department of Genetics and Genomic Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue, Box 1498 New York NY 10029 USA
| | - Anne J Stokka
- Department of Biomedicine University of Bergen Norway.,The Biotechnology Centre of Oslo University of Oslo Norway
| | - Knut Teigen
- Department of Biomedicine University of Bergen Norway
| | - Ole A Andersen
- Department of Biomedicine University of Bergen Norway.,Evotec (UK) Ltd .Abingdon UK
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31
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Turki A, Ueda K, Cheng B, Giezen A, Salvarinova R, Stockler-Ipsiroglu S, Elango R. The Indicator Amino Acid Oxidation Method with the Use of l-[1-13C]Leucine Suggests a Higher than Currently Recommended Protein Requirement in Children with Phenylketonuria. J Nutr 2017; 147:211-217. [PMID: 28053173 DOI: 10.3945/jn.116.240218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/01/2016] [Accepted: 12/01/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Phenylketonuria is characterized by mutations in the Phe hydroxylase gene that leads to the accumulation of Phe in plasma and the brain. The standard of care for phenylketonuria is nutritional management with dietary restriction of Phe and the provision of sufficient protein and energy for growth and health maintenance. The protein requirement in children with phenylketonuria is empirically determined based upon phenylketonuria nutritional guidelines that are adjusted individually in response to biochemical markers and growth. OBJECTIVE We determined dietary protein requirements in children with phenylketonuria with the use of the indicator amino acid oxidation (IAAO) technique, with l-[1-13C]Leu as the indicator amino acid. METHODS Four children (2 males; 2 females) aged 9-18 y with phenylketonuria [mild hyperphenylalanemia (mHPA); 6-10 mg/dL (360-600 μmol/L)] were recruited to participate in ≥7 separate test protein intakes (range: 0.2-3.2 g ⋅ kg-1 ⋅ d-1) with the IAAO protocol with the use of l-[1-13C]Leu followed by the collection of breath and urine samples over 8 h. The diets were isocaloric and provided energy at 1.7 times the resting energy expenditure. Protein was provided as a crystalline amino acid mixture based on an egg protein pattern, except Phe and Leu, which were maintained at a constant across intakes. Protein requirement was determined with the use of a 2-phase linear-regression crossover analysis of the rate of l-[1-13C]Leu tracer oxidation. RESULTS The mean protein requirement was determined to be 1.85 g ⋅ kg-1 ⋅ d-1 (R2 = 0.66; 95% CI: 1.37, 2.33). This result is substantially higher than the 2014 phenylketonuria recommendations (1.14-1.33 g ⋅ kg-1 ⋅ d-1; based on 120-140% above the current RDA for age). CONCLUSIONS To our knowledge, this is the first study to directly define a quantitative requirement for protein intake in children with mHPA and indicates that current protein recommendations in children with phenylketonuria may be insufficient. This trial was registered at clinicaltrials.gov as NCT01965691.
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Affiliation(s)
- Abrar Turki
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Pediatrics and
| | - Keiko Ueda
- Department of Pediatrics and.,Division of Biochemical Diseases, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Barbara Cheng
- Department of Pediatrics and.,Division of Biochemical Diseases, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Alette Giezen
- Department of Pediatrics and.,Division of Biochemical Diseases, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Ramona Salvarinova
- Department of Pediatrics and.,Division of Biochemical Diseases, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Sylvia Stockler-Ipsiroglu
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Pediatrics and.,Division of Biochemical Diseases, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Rajavel Elango
- Department of Pediatrics and .,School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; and.,Division of Biochemical Diseases, BC Children's Hospital, Vancouver, British Columbia, Canada
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Leandro J, Saraste J, Leandro P, Flatmark T. PKU mutation p.G46S prevents the stereospecific binding of l-phenylalanine to the dimer of human phenylalanine hydroxylase regulatory domain. FEBS Open Bio 2017; 7:195-203. [PMID: 28174686 PMCID: PMC5292662 DOI: 10.1002/2211-5463.12175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 12/01/2016] [Accepted: 12/03/2016] [Indexed: 11/23/2022] Open
Abstract
Mammalian phenylalanine hydroxylase (PAH) has a potential allosteric regulatory binding site for l‐phenylalanine (l‐Phe), in addition to its catalytic site. This arrangement is supported by a crystal structure of a homodimeric truncated form of the regulatory domain of human PAH (hPAH‐RD1–118/19–118) [Patel D et al. (2016) Sci Rep doi: 10.1038/srep23748]. In this study, a fusion protein of the domain (MBP‐(pepXa)‐hPAH‐RD1–120) was overexpressed and recovered in a metastable and soluble state, which allowed the isolation of a dimeric and a monomeric fusion protein. When cleaved from MBP, hPAH‐RD forms aggregates which are stereospecifically inhibited by l‐Phe (> 95%) at low physiological concentrations. Aggregation of the cleaved dimer of the mutant form hPAH‐G46S‐RD was not inhibited by l‐Phe, which is compatible with structurally/conformationally changed βαββαβ ACT domain folds in the mutant.
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Affiliation(s)
- João Leandro
- Department of Biomedicine University of Bergen Norway; Metabolism and Genetics Group Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL) Faculty of Pharmacy University of Lisbon Portugal
| | | | - Paula Leandro
- Metabolism and Genetics Group Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL) Faculty of Pharmacy University of Lisbon Portugal
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Sumaily KM, Mujamammi AH. Phenylketonuria: A new look at an old topic, advances in laboratory diagnosis, and therapeutic strategies. Int J Health Sci (Qassim) 2017; 11:63-70. [PMID: 29114196 PMCID: PMC5669513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Disorders of protein metabolism are the most common diseases among discovered inherited metabolic disorders. Phenylketonuria (PKU), a relatively common disorder that is responsive to treatment, is an inherited autosomal recessive disorder caused by a deficiency in phenylalanine hydroxylase (PAH) or one of several enzymes mediating biosynthesis or regeneration of the PAH cofactor tetrahydrobiopterin. The objective of this review is to discuss therapeutic strategies that have recently emerged for curing patients with PKU, which have demonstrated promising improvements in managing these patients. Data sourcing included a systematic literature review of PubMed with a focus on emerging knowledge pertaining to this well-studied disease. Recent advances in laboratory diagnosis and therapeutic strategies were described. Collectively, promising and rapid enhancements in neonatal diagnostic technologies and recently emerged therapeutic strategies are paving the way for early diagnosis and treating many inborn errors of metabolism, such as PKU.
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Affiliation(s)
- Khalid M. Sumaily
- Department of Pathology, Clinical Biochemistry Unit, King Saud University Medical City, King Saud University, Riyadh Saudi Arabia,Address for correspondence: Khalid M. Sumaily, Consultant in Medical Biochemistry and Biochemical Genetics, Department of Pathology, Clinical Biochemistry Unit, College of Medicine, King Saud University Medical City, King Saud University, P.O. Box 2925 (30), Riyadh 11461, Saudi Arabia. Phone: +00966114698502. Mobile: 00966540904761. E-mail:
| | - Ahmed H. Mujamammi
- Department of Pathology, Clinical Biochemistry Unit, King Saud University Medical City, King Saud University, Riyadh Saudi Arabia
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Gélvez N, Acosta J, López G, Castro D, Prieto JC, Bermúdez M, Tamayo ML. [Phenotypic and molecular characterization of a Colombian family with phenylketonuria]. Biomedica 2016; 36:390-6. [PMID: 27869385 DOI: 10.7705/biomedica.v36i3.2639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/12/2016] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Phenylketonuria is a metabolic disorder characterized by severe neurological involvement and behavioral disorder, whose early diagnosis enables an effective treatment to avoid disease sequelae, thus changing the prognosis. Objective: To characterize a family with phenylketonuria in Colombia at clinical, biochemical and molecular levels. Materials and methods: The population consisted of seven individuals of a consanguineous family with four children with suggestive symptoms of phenylketonuria. After signing an informed consent, blood and urine samples were taken for colorimetric tests and high performance liquid and thin layer chromatographies. DNA extraction and sequencing of the 13 exons of the PAH gene were performed in all subjects. We designed primers for each exon with the Primer 3 software using automatic sequencing equipment Abiprism 3100 Avant. Sequences were analyzed using the SeqScape, v2.0, software. Results: We described the clinical and molecular characteristics of a Colombian family with phenylketonuria and confirmed the presence of the mutation c.398_401delATCA. We established a genotype-phenotype correlation, highlighting the interesting clinical variability found among the affected patients despite having the same mutation in all of them. Conclusions: Early recognition of this disease is very important to prevent its neurological and psychological sequelae, given that patients reach old age without diagnosis or proper management.
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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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36
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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: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Dateki S, Watanabe S, Nakatomi A, Kinoshita E, Matsumoto T, Yoshiura KI, Moriuchi H. Genetic background of hyperphenylalaninemia in Nagasaki, Japan. Pediatr Int 2016; 58:431-3. [PMID: 27173423 DOI: 10.1111/ped.12924] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 11/30/2015] [Accepted: 01/13/2016] [Indexed: 11/28/2022]
Abstract
Phenylketonuria (PKU) and related hyperphenylalaninemia (HPA) are caused by a deficiency in hepatic phenylalanine hydroxylase (PAH). The incidence of PKU in Nagasaki prefecture is higher than that in all parts of Japan (1/15 894 vs 1/120 000). To investigate the genetic background of patients with HPA in Nagasaki prefecture, mutation analysis was done in 14 patients with PKU or mild HPA. Homozygous or compound heterozygous PAH mutations were identified in all the patients. The spectrum of PAH mutations in the cohort was broad and similar to those in all parts of Japan and East Asian countries. R53H is the most common mutation in patients with mild HPA. The present results provide further support for genotype-phenotype correlations in patients with HPA. The high incidence of PKU in Nagasaki, the westernmost part of Japan, might be due to migration of people with PAH mutations from China and Korea, and geographic factors.
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Affiliation(s)
- Sumito Dateki
- Department of Pediatrics, Nagasaki University Hospital, Nagasaki, Japan
| | - Satoshi Watanabe
- Department of Pediatrics, Nagasaki University Hospital, Nagasaki, Japan.,Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Akiko Nakatomi
- Department of Pediatrics, Nagasaki University Hospital, Nagasaki, Japan
| | | | - Tadashi Matsumoto
- Division of Developmental Disabilities, Misakaenosono Mutsumi Developmental, Medical and Welfare Center, Isahaya, Japan
| | - Koh-Ichiro Yoshiura
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Hiroyuki Moriuchi
- Department of Pediatrics, Nagasaki University Hospital, Nagasaki, Japan
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38
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Ren G, Dong Z, Liu C, Liu Y, Luan Z, Liu Q, Bao X, Wang S. [The expression of phenylalanine hydroxylase in the brain of ragworm Neanthes japonica (Polychaeta, Annelida)]. Sheng Wu Gong Cheng Xue Bao 2016; 32:518-526. [PMID: 28853273 DOI: 10.13345/j.cjb.150550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Phenylalanine hydroxylase (PAH) is a member of aromatic amino acid hydroxylase (AAAHs) family, and catalyze phenylalanine (Phe) into tyrosine (Tyr). Using immunological and RT-PCR methods to prove the existence of phenylalanine hydroxylase (PAH) gene in the brain of Neanthes japonica in protein and nucleic acid level. Using Western blotting to detect the pah immunogenicity of Neanthes japonica. Making paraffin sections and using immunohistochemical technique to identify the presence and distribution of the phenylalanine hydroxylase gene in the brain of Neanthes japonica. Clone pah gene from the brain of Neanthes japonica by RT-PCR, constructing plasmid and transferring into E. coli to amplification, picking a single homogeneous colony, double digesting then making sequence and comparing homology. Western blotting results showed that the expression of the protein is present in Neanthes japonica brain, immunohistochemistry technique results showed that phenylalanine hydroxylase mainly expressed in abdominal of forebrain, dorsal and sides of midbrain. RT-PCR technique results showed that the phenylalanine hydroxylase exist in the brain of Neanthes japonica and has a high homology with others animals. PAH is present in the lower organisms Neanthes japonica, in protein and nucleic acid level. Which provide the foundation for further study the evolution of aromatic amino acid hydroxylase genes in invertebrate.
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Affiliation(s)
- Guimin Ren
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Liaoning Medical University, Jinzhou 121000, Liaoning, China
| | - Zhe Dong
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Liaoning Medical University, Jinzhou 121000, Liaoning, China
| | - Chao Liu
- Department of Developmental Biology, School of Basic Medical Sciences, Liaoning Medical University, Jinzhou 121000, Liaoning, China
| | - Yimeng Liu
- Department of Developmental Biology, School of Basic Medical Sciences, Liaoning Medical University, Jinzhou 121000, Liaoning, China
| | - Zhidong Luan
- Department of Developmental Biology, School of Basic Medical Sciences, Liaoning Medical University, Jinzhou 121000, Liaoning, China
| | - Qi Liu
- Laboratory of Insect Brain Biology, Northeast Normal University, Changchun 130024, Jilin, China
| | - Xuexiang Bao
- Laboratory of Insect Brain Biology, Northeast Normal University, Changchun 130024, Jilin, China
| | - Shun Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Liaoning Medical University, Jinzhou 121000, Liaoning, China
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Arturo EC, Gupta K, Héroux A, Stith L, Cross PJ, Parker EJ, Loll PJ, Jaffe EK. 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] [What about the content of this article? (0)] [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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40
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Ding Y, Li XY, Liu YP, Li DX, Song JQ, Li MQ, Qin YP, Wu TF, Yang YL. [Psychomotor retardation and intermitent convulsions for 8 months in an infant]. Zhongguo Dang Dai Er Ke Za Zhi 2016; 18:67-71. [PMID: 26781416 PMCID: PMC7390091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 11/23/2015] [Indexed: 11/12/2023]
Abstract
This study reports a boy with psychomotor retardation and epilepsy due to maternal phenylketonuria (PKU). The boy was admitted at the age of 20 months because of psychomotor retardation and epilepsy. He had seizures from the age of 1 year. His development quotient was 43. He presented with microcephaly, normal skin and hair color. Brain MRI scan showed mild cerebral white matter demyelination, broadening bilateral lateral ventricle and foramen magnum stricture. Chromosome karyotype, urine organic acids, blood amino acids and acylcarnitines were normal. His mother had mental retardation from her childhood. She presented with learning difficulties and yellow hair. Her premarriage health examinations were normal. She married a healthy man at age of 26 years. When she visited us at 28 years old, PKU was found by markedly elevated blood phenylalanine (916.54 μmol/L vs normal range 20-120 μmol/L). On her phenylalanine hydroxylase (PAH) gene, a homozygous mutations c.611A>G (p.Y204C) was identified, which confirmed the diagnosis of PAH-deficient PKU. Her child carries a heterozygous mutation c.611A>G with normal blood phenylalanine. Her husband had no any mutation on PAH. It is concluded that family investigation is very important for the etiological diagnosis of the children with mental retardation and epilepsy. Carefully clinical and metabolic survey should be performed for the parents with mental problems to identify parental diseases-associated child brain damage, such as maternal PKU.
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Affiliation(s)
- Yuan Ding
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
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42
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Ding Y, Li XY, Liu YP, Li DX, Song JQ, Li MQ, Qin YP, Wu TF, Yang YL. [Psychomotor retardation and intermitent convulsions for 8 months in an infant]. Zhongguo Dang Dai Er Ke Za Zhi 2016; 18:67-71. [PMID: 26781416 PMCID: PMC7390091 DOI: 10.7499/j.issn.1008-8830.2016.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 11/23/2015] [Indexed: 06/05/2023]
Abstract
This study reports a boy with psychomotor retardation and epilepsy due to maternal phenylketonuria (PKU). The boy was admitted at the age of 20 months because of psychomotor retardation and epilepsy. He had seizures from the age of 1 year. His development quotient was 43. He presented with microcephaly, normal skin and hair color. Brain MRI scan showed mild cerebral white matter demyelination, broadening bilateral lateral ventricle and foramen magnum stricture. Chromosome karyotype, urine organic acids, blood amino acids and acylcarnitines were normal. His mother had mental retardation from her childhood. She presented with learning difficulties and yellow hair. Her premarriage health examinations were normal. She married a healthy man at age of 26 years. When she visited us at 28 years old, PKU was found by markedly elevated blood phenylalanine (916.54 μmol/L vs normal range 20-120 μmol/L). On her phenylalanine hydroxylase (PAH) gene, a homozygous mutations c.611A>G (p.Y204C) was identified, which confirmed the diagnosis of PAH-deficient PKU. Her child carries a heterozygous mutation c.611A>G with normal blood phenylalanine. Her husband had no any mutation on PAH. It is concluded that family investigation is very important for the etiological diagnosis of the children with mental retardation and epilepsy. Carefully clinical and metabolic survey should be performed for the parents with mental problems to identify parental diseases-associated child brain damage, such as maternal PKU.
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Affiliation(s)
- Yuan Ding
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China.
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Abstract
BACKGROUND Phenylketonuria is an inherited metabolic disorder characterised by an absence or deficiency of the enzyme phenylalanine hydroxylase. The aim of treatment is to lower blood phenylalanine concentrations to the recommended therapeutic range to prevent developmental delay and support normal growth. Current treatment consists of a low-phenylalanine diet in combination with a protein substitute which is free from or low in phenylalanine. Guidance regarding the use, dosage, and distribution of dosage of the protein substitute over a 24-hour period is unclear, and there is variation in recommendations among treatment centres. This is an update of a Cochrane review first published in 2005, and previously updated in 2008. OBJECTIVES To assess the benefits and adverse effects of protein substitute, its dosage, and distribution of dose in children and adults with phenylketonuria who are adhering to a low-phenylalanine diet. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which consists of references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. We also contacted manufacturers of the phenylalanine-free and low-phenylalanine protein substitutes for any data from published and unpublished randomised controlled trials.Date of the most recent search of the Group's Inborn Errors of Metabolism Trials Register: 03 April 2014. SELECTION CRITERIA All randomised or quasi-randomised controlled trials comparing: any dose of protein substitute with no protein substitute; an alternative dosage; or the same dose, but given as frequent small doses throughout the day compared with the same total daily dose given as larger boluses less frequently. DATA COLLECTION AND ANALYSIS Both authors independently extracted data and assessed trial quality. MAIN RESULTS Three trials (69 participants) are included in this review. One trial investigated the use of protein substitute in 16 participants, while a further two trials investigated the dosage of protein substitute in a total of 53 participants. Due to issues with data presentation in each trial, described in full in the review, formal statistical analyses of the data were impossible. Investigators will be contacted for further information. AUTHORS' CONCLUSIONS No conclusions could be drawn about the short- or long-term use of protein substitute in phenylketonuria due to the lack of adequate or analysable trial data. Additional data and randomised controlled trials are needed to investigate the use of protein substitute in phenylketonuria. Until further evidence is available, current practice in the use of protein substitute should continue to be monitored with care.
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Affiliation(s)
- Sarah HL Yi
- Emory Genetics Metabolic Nutrition Program2165 N. Decatur RoadDecaturGeorgiaUSA30033
| | - Rani H Singh
- Emory University School of MedicineDepartment of Human Genetics2165 North Decatur RoadDecaturGeorgiaUSA30033
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Yu W, He J, Yang X, Zou H, Gui J, Wang R, Yang L, Wang Z, Lei Q. Characterization of phenylalanine hydroxylase gene mutations in phenylketonuria in Xinjiang of China. Int J Clin Exp Med 2014; 7:4406-4412. [PMID: 25550961 PMCID: PMC4276219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/30/2014] [Indexed: 06/04/2023]
Abstract
To investigate the spectrum and frequency of phenylalanine hydroxylase (PAH) gene mutations in phenylketonuria (PKU) patients in Xinjiang, China. Polymerase chain reaction (PCR), in combination with single-strand conformation polymorphism (SSCP) and DNA sequencing analyses were performed, to screen potential mutations in the PAH gene in 46 individual PKU patients. Direct DNA sequencing was used to analyze the all of the exons in the PAH gene, including the promoter and flanking intron regions, in another 15 PKU patients. Our results indicated that, 30 different mutation types were identified in all 122 PAH alleles, with the mutation detection rate of 78.7% (96/122). Four novel mutations, i.e., 5'-Flanking -626G>A, 5'-Flanking -480DelACT, S196fsX4, and IVS8+1G>C, were identified for the first time. Similar to other regions in North China, R243Q, EX6-96A>G, IVS4-1A>G, R111X, and Y356X were the most prevalent PAH mutations in PKU patients from Xinjiang. Additionally, common mutations showed different frequencies in Xinjiang, when compared to other areas. Furthermore, sixteen different PAH gene mutation types were identified for the first time in the minorities in Xinjiang. Distinctive mutation spectrum of PAH gene in PKU patients from Xinjiang were characterized, which may promote the construction of PAH gene mutation database and serve as valuable tools for genetic diagnosis and counseling, and prognostic evaluation for PKU cases in the local area.
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Affiliation(s)
- Wuzhong Yu
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
| | - Jiang He
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
| | - Xi Yang
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
| | - Hongyun Zou
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
| | - Junhao Gui
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
| | - Rui Wang
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
| | - Liu Yang
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
| | - Zheng Wang
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
| | - Quan Lei
- Clinical Medical Institute, Urumqi General Hospital of Lanzhou Military Area Command, PLA Urumqi 830000, Xinjiang, China
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Vannini L, Augustine Dunn W, Reed TW, Willis JH. Changes in transcript abundance for cuticular proteins and other genes three hours after a blood meal in Anopheles gambiae. Insect Biochem Mol Biol 2014; 44:33-43. [PMID: 24269292 PMCID: PMC3970321 DOI: 10.1016/j.ibmb.2013.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/24/2013] [Accepted: 11/05/2013] [Indexed: 05/03/2023]
Abstract
Numerous studies have examined changes in transcript levels after Anopheles gambiae takes a blood meal. Marinotti et al. (2006) used microarrays and reported massive changes in transcript levels 3 h after feeding (BF3h) compared to non-blood fed (NBF). We were intrigued by the number of transcripts for structural cuticular proteins (CPs) that showed such major differences in levels and employed paired-end (50 bp) RNA-seq technology to compare whole body transcriptomes from 5-day-old females NBF and BF3h. We detected transcripts for the majority of CPs (164/243) but levels of only 12 were significantly altered by the blood meal. While relative transcript levels of NBF females were somewhat similar to the microarray data, there were major differences in BF3h animals, resulting in levels of many transcripts, both for CPs and other genes changing in the opposite direction. We compared our data also to other studies done with both microarrays and RNA-seq. Findings were consistent that a small number of CP genes have transcripts that persist even in 5-day-old adults. Some of these transcripts showed diurnal rhythms (Rund et al., 2013; Rinker et al., 2013). In situ hybridization revealed that transcripts for several of these CP genes were found exclusively or predominantly in the eye. Transcripts other than for CPs that changed in response to blood-feeding were predominantly expressed in midgut and Malpighian tubules. Even in these tissues, genes responsible for proteins with similar functions, such as immunity or digestion, responded differently, with transcript levels for some rising and others falling. These data demonstrate that genes coding for some CPs are dynamic in expression even in adults and that the response to a blood meal is rapid and precisely orchestrated.
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Affiliation(s)
- Laura Vannini
- University of Georgia, Cellular Biology, Athens, GA 30602, USA.
| | - W Augustine Dunn
- University of California Irvine, Molecular Biology and Biochemistry, Irvine, CA 92697, USA.
| | - Tyler W Reed
- University of Georgia, Cellular Biology, Athens, GA 30602, USA.
| | - Judith H Willis
- University of Georgia, Cellular Biology, Athens, GA 30602, USA.
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Cleary M, Trefz F, Muntau AC, Feillet F, van Spronsen FJ, Burlina A, Bélanger-Quintana A, Giżewska M, Gasteyger C, Bettiol E, Blau N, MacDonald A. Fluctuations in phenylalanine concentrations in phenylketonuria: a review of possible relationships with outcomes. Mol Genet Metab 2013; 110:418-23. [PMID: 24090706 DOI: 10.1016/j.ymgme.2013.09.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/03/2013] [Indexed: 11/21/2022]
Abstract
Fluctuations in blood phenylalanine concentrations may be an important determinant of intellectual outcome in patients with early and continuously treated phenylketonuria (PKU). This review evaluates the studies on phenylalanine fluctuations, factors affecting fluctuations, and if stabilizing phenylalanine concentrations affects outcomes, particularly neurocognitive outcome. Electronic literature searches of Embase and PubMed were performed for English-language publications, and the bibliographies of identified publications were also searched. In patients with PKU, phenylalanine concentrations are highest in the morning. Factors that can affect phenylalanine fluctuations include age, diet, timing and dosing of protein substitute and energy intake, dietary adherence, phenylalanine hydroxylase genotype, changes in dietary phenylalanine intake and protein metabolism, illness, and growth rate. Even distribution of phenylalanine-free protein substitute intake throughout 24h may reduce blood phenylalanine fluctuations. Patients responsive to and treated with 6R-tetrahydrobiopterin seem to have less fluctuation in their blood phenylalanine concentrations than controls. An increase in blood phenylalanine concentration may result in increased brain and cerebrospinal fluid phenylalanine concentrations within hours. Although some evidence suggests that stabilization of blood phenylalanine concentrations may have benefits in patients with PKU, more studies are needed to distinguish the effects of blood phenylalanine fluctuations from those of poor metabolic control.
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Affiliation(s)
- Maureen Cleary
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
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Stevenson M, McNaughton N. A comparison of phenylketonuria with attention deficit hyperactivity disorder: do markedly different aetiologies deliver common phenotypes? Brain Res Bull 2013; 99:63-83. [PMID: 24140048 DOI: 10.1016/j.brainresbull.2013.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 09/04/2013] [Accepted: 10/07/2013] [Indexed: 01/21/2023]
Abstract
Phenylketonuria (PKU) is a well-defined metabolic disorder arising from a mutation that disrupts phenylalanine metabolism and so produces a variety of neural changes indirectly. Severe cognitive impairment can be prevented by dietary treatment; however, residual symptoms may be reported. These residual symptoms appear to overlap a more prevalent childhood disorder: Attention Deficit/Hyperactivity Disorder (ADHD). However, the aetiology of ADHD is a vast contrast to PKU: it seems to arise from a complex combination of genes; and it has a substantial environmental component. We ask whether these two disorders result from two vastly different genotypes that converge on a specific core phenotype that includes similar dysfunctions of Gray's (Gray, 1982) Behavioural Inhibition System (BIS), coupled with other disorder-specific dysfunctions. If so, we believe comparison of the commonalities will allow greater understanding of the neuropsychology of both disorders. We review in detail the aetiology, treatment, neural pathology, cognitive deficits and electrophysiological abnormalities of PKU; and compare this with selected directly matching aspects of ADHD. The biochemical and neural pathologies of PKU and ADHD are quite distinct in their causes and detail; but they result in the disorder in the brain of large amino acid levels, dopamine and white matter that are very similar and could explain the overlap of symptoms within and between the PKU and ADHD spectra. The common deficits affect visual function, motor function, attention, working memory, planning, and inhibition. For each of PKU and ADHD separately, a subset of deficits has been attributed to a primary dysfunction of behavioural inhibition. In the case of ADHD (excluding the inattentive subtype) this has been proposed to involve a specific failure of the BIS; and we suggest that this is also true of PKU. This accounts for a substantial proportion of the parallels in the superficial symptoms of both disorders and we see this as linked to prefrontal, rather than more general, dysfunction of the BIS.
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Demirdas S, Maurice-Stam H, Boelen CCA, Hofstede FC, Janssen MCH, Langendonk JG, Mulder MF, Rubio-Gozalbo ME, van Spronsen FJ, de Vries M, Grootenhuis MA, Bosch AM. Evaluation of quality of life in PKU before and after introducing tetrahydrobiopterin (BH4); a prospective multi-center cohort study. Mol Genet Metab 2013; 110 Suppl:S49-56. [PMID: 24100246 DOI: 10.1016/j.ymgme.2013.09.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 09/19/2013] [Indexed: 11/26/2022]
Abstract
BACKGROUND Phenylketonuria (PKU) is a rare inborn error of metabolism caused by phenylalanine hydroxylase enzyme (PAH) deficiency. Treatment constitutes a strict Phe restricted diet with unpalatable amino acid supplements. Residual PAH activity enhancement with its cofactor tetrahydrobiopterin (BH4) is a novel treatment which increases dietary tolerance in some patients and permits dietary relaxation. Relaxation of diet may improve health related quality of life (HRQoL). This prospective cohort study aims to evaluate HRQoL of patients with PKU and effects of BH4 treatment on HRQoL. METHODS Patients aged 4years and older, diagnosed through newborn screening and early and continuously treated, were recruited from eight metabolic centers. Patients and mothers completed validated generic and chronic health-conditions HRQoL questionnaires (PedsQL, TAAQOL, and DISABKIDS) twice: before and after testing BH4 responsivity. Baseline results were compared to the general population. Data collected after BH4 testing was used to find differences in HRQoL between BH4 unresponsive patients and BH4 responsive patients after one year of treatment with BH4. Also a within patient comparison was performed to find differences in HRQoL before and after treatment with BH4. RESULTS 69/81 (85%) patients completed the questionnaires before BH4 responsivity testing, and 45/69 (65%) participated again after testing. Overall PKU patients demonstrated normal HRQoL. However, some significant differences were found when compared to the general population. A significantly higher (thus better) score on the PedsQL was reported by children 8-12 years on physical functioning and by children 13-17 years on total and psychosocial functioning. Furthermore, adult patients reported significantly lower (thus worse) scores in the TAAQOL cognitive domain. 10 patients proved to be responsive to BH4 treatment; however improvement in their HRQoL after relaxation of diet could not be demonstrated.
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Affiliation(s)
- Serwet Demirdas
- Department of Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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Polak E, Ficek A, Radvanszky J, Soltysova A, Urge O, Cmelova E, Kantarska D, Kadasi L. Phenylalanine hydroxylase deficiency in the Slovak population: genotype-phenotype correlations and genotype-based predictions of BH4-responsiveness. Gene 2013; 526:347-55. [PMID: 23764561 DOI: 10.1016/j.gene.2013.05.057] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 05/08/2013] [Accepted: 05/20/2013] [Indexed: 10/26/2022]
Abstract
We investigated the mutation spectrum of the phenylalanine hydroxylase gene (PAH) in a cohort of patients from 135 Slovak PKU families. Mutational screening of the known coding region, including conventional intron splice sites, was performed using high-resolution melting analysis, with subsequent sequencing analysis of the samples showing deviated melting profiles compared to control samples. The PAH gene was also screened for deletions and duplications using MLPA analysis. Forty-eight different disease causing mutations were identified in our patient group, including 30 missense, 8 splicing, 7 nonsense, 2 large deletions and 1 small deletion with frameshift; giving a detection rate of 97.6%. The most prevalent mutation was the p.R408W, occurring in 47% of all alleles, which concurs with results from neighboring and other Slavic countries. Other frequent mutations were: p.R158Q (5.3%), IVS12+1G>A (5.3%), p.R252W (5.1%), p.R261Q (3.9%) and p.A403V (3.6%). We also identified three novel missense mutations: p.F233I, p.R270I, p.F331S and one novel variant: c.-30A>T in the proximal part of the PAH gene promoter. A spectrum of 84 different genotypes was observed and a genotype based predictions of BH4-responsiveness were assessed. Among all genotypes, 36 were predicted to be BH4-responsive represented by 51 PKU families. In addition, genotype-phenotype correlations were performed.
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Affiliation(s)
- Emil Polak
- Comenius University, Faculty of Natural Sciences, Department of Molecular Biology, Mlynska Dolina, 842 15 Bratislava, Slovak Republic.
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Ronau JA, Paul LN, Fuchs JE, Corn IR, Wagner KT, Liedl KR, Abu-Omar MM, Das C. An additional substrate binding site in a bacterial phenylalanine hydroxylase. Eur Biophys J 2013; 42:691-708. [PMID: 23860686 PMCID: PMC3972754 DOI: 10.1007/s00249-013-0919-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 06/20/2013] [Accepted: 06/26/2013] [Indexed: 01/07/2023]
Abstract
Phenylalanine hydroxylase (PAH) is a non-heme iron enzyme that catalyzes oxidation of phenylalanine to tyrosine, a reaction that must be kept under tight regulatory control. Mammalian PAH has a regulatory domain in which binding of the substrate leads to allosteric activation of the enzyme. However, the existence of PAH regulation in evolutionarily distant organisms, for example some bacteria in which it occurs, has so far been underappreciated. In an attempt to crystallographically characterize substrate binding by PAH from Chromobacterium violaceum, a single-domain monomeric enzyme, electron density for phenylalanine was observed at a distal site 15.7 Å from the active site. Isothermal titration calorimetry (ITC) experiments revealed a dissociation constant of 24 ± 1.1 μM for phenylalanine. Under the same conditions, ITC revealed no detectable binding for alanine, tyrosine, or isoleucine, indicating the distal site may be selective for phenylalanine. Point mutations of amino acid residues in the distal site that contact phenylalanine (F258A, Y155A, T254A) led to impaired binding, consistent with the presence of distal site binding in solution. Although kinetic analysis revealed that the distal site mutants suffer discernible loss of their catalytic activity, X-ray crystallographic analysis of Y155A and F258A, the two mutants with the most noticeable decrease in activity, revealed no discernible change in the structure of their active sites, suggesting that the effect of distal binding may result from protein dynamics in solution.
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Affiliation(s)
- Judith A. Ronau
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA
| | - Lake N. Paul
- Bindley Biosciences Center, Purdue University, West Lafayette, IN 47907, USA
| | - Julian E. Fuchs
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Isaac R. Corn
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA
| | - Kyle T. Wagner
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Mahdi M. Abu-Omar
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA
| | - Chittaranjan Das
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA,To whom correspondence should be addressed: Chittaranjan Das, Brown Laboratory of Chemistry, 560 Oval Drive, West Lafayette, IN, 47907, (765)-494-5478, Fax: (765)-494-0239,
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