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Graziani C, Barile A, Antonelli L, Fiorillo A, Ilari A, Vetica F, di Salvo ML, Paiardini A, Tramonti A, Contestabile R. The Z isomer of pyridoxilidenerhodanine 5'-phosphate is an efficient inhibitor of human pyridoxine 5'-phosphate oxidase, a crucial enzyme in vitamin B 6 salvage pathway and a potential chemotherapeutic target. FEBS J 2024. [PMID: 39288205 DOI: 10.1111/febs.17274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 07/30/2024] [Accepted: 09/02/2024] [Indexed: 09/19/2024]
Abstract
Pyridoxal 5'-phosphate (PLP), the catalytically active form of vitamin B6, acts as a cofactor in many metabolic processes. In humans, PLP is produced in the reactions catalysed by pyridox(am)ine 5'-phosphate oxidase (PNPO) and pyridoxal kinase (PDXK). Both PNPO and PDXK are involved in cancer progression of many tumours. The silencing of PNPO and PDXK encoding genes determines a strong reduction in tumour size and neoplastic cell invasiveness in models of acute myeloid leukaemia (in the case of PDXK) and ovarian and breast cancer (in the case of PNPO). In the present work, we demonstrate that pyridoxilidenerhodanine 5'-phosphate (PLP-R), a PLP analogue that has been tested by other authors on malignant cell lines reporting a reduction in proliferation, inhibits PNPO in vitro following a mixed competitive and allosteric mechanism. We also show that the unphosphorylated precursor of this inhibitor (PL-R), which has more favourable pharmacokinetic properties according to our predictions, is phosphorylated by PDXK and therefore transformed into PLP-R. On this ground, we propose the prototype of a novel prodrug-drug system as a useful starting point for the development of new, potential, antineoplastic agents.
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Affiliation(s)
- Claudio Graziani
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Italy
| | - Anna Barile
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Lorenzo Antonelli
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Italy
| | - Annarita Fiorillo
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Italy
| | - Andrea Ilari
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy
| | | | - Martino Luigi di Salvo
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Italy
| | - Alessandro Paiardini
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Italy
| | - Angela Tramonti
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Italy
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
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2
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Machover D, Almohamad W, Castagné V, Desterke C, Gomez L, Goldschmidt E. Treatment of patients with carcinomas in advanced stages with 5-fluorouracil, folinic acid and pyridoxine in tandem. Sci Rep 2024; 14:12054. [PMID: 38802419 PMCID: PMC11130240 DOI: 10.1038/s41598-024-62860-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 05/22/2024] [Indexed: 05/29/2024] Open
Abstract
The effect of high-dose pyridoxine (PN) on activity of 5-fluorouracil (FUra) and folinic acid (FA)-containing regimens was studied in 50 patients including 14 with digestive tract, and 36 with breast carcinomas (BC) in advanced stages with poor prognostic characteristics. Patients with colorectal, and pancreas adenocarcinoma received oxaliplatin, irinotecan, FUra, FA (Folfirinox), and patients with squamous cell carcinoma of the esophagus had paclitaxel, carboplatin, FUra, FA (TCbF). Patients with BC received AVCF (doxorubicin, vinorelbine, cyclophosphamide, FUra, FA) followed by TCbF or TCbF only, and patients who overexpressed HER2 received TCbF plus trastuzumab and pertuzumab. PN (1000-3000 mg/day iv) preceded each administration of FUra and FA. 47 patients (94%) responded, including 16 (32%) with CR. Median tumor reduction was 93%. Median event-free survival (EFS) was 37.7 months. The 25 patients with tumor shrinkage ≥ 91% had EFS of 52% from 42 months onwards. Unexpected toxicity did not occur. PN enhances potency of chemotherapy regimens comprising FUra and FA.
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Affiliation(s)
- David Machover
- INSERM U935-UA09, University Paris-Saclay, Paul-Brousse Hospital, 12, Avenue Paul-Vaillant-Couturier, 94800, Villejuif, France.
| | - Wathek Almohamad
- Department of Medical Oncology, University Paris-Saclay, Paul-Brousse Hospital, Assistance Publique-Hôpitaux de Paris (APHP), 94800, Villejuif, France
| | - Vincent Castagné
- Department of Pharmacy, University Paris-Saclay, Paul-Brousse Hospital, APHP, 94800, Villejuif, France
| | - Christophe Desterke
- INSERM U935-UA09, University Paris-Saclay, Paul-Brousse Hospital, 12, Avenue Paul-Vaillant-Couturier, 94800, Villejuif, France
| | - Léa Gomez
- Department of Biophysics and Nuclear Medicine, University Paris-Saclay, Kremlin-Bicêtre Hospital, APHP, 94270, Le Kremlin-Bicêtre, France
| | - Emma Goldschmidt
- Department of Medical Oncology, University Paris-Saclay, Paul-Brousse Hospital, Assistance Publique-Hôpitaux de Paris (APHP), 94800, Villejuif, France
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3
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Barile A, Graziani C, Antonelli L, Parroni A, Fiorillo A, di Salvo ML, Ilari A, Giorgi A, Rosignoli S, Paiardini A, Contestabile R, Tramonti A. Identification of the pyridoxal 5'-phosphate allosteric site in human pyridox(am)ine 5'-phosphate oxidase. Protein Sci 2024; 33:e4900. [PMID: 38284493 PMCID: PMC10804683 DOI: 10.1002/pro.4900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/18/2023] [Accepted: 12/31/2023] [Indexed: 01/30/2024]
Abstract
Adequate levels of pyridoxal 5'-phosphate (PLP), the catalytically active form of vitamin B6 , and its proper distribution in the body are essential for human health. The PLP recycling pathway plays a crucial role in these processes and its defects cause severe neurological diseases. The enzyme pyridox(am)ine 5'-phosphate oxidase (PNPO), whose catalytic action yields PLP, is one of the key players in this pathway. Mutations in the gene encoding PNPO are responsible for a severe form of neonatal epilepsy. Recently, PNPO has also been described as a potential target for chemotherapeutic agents. Our laboratory has highlighted the crucial role of PNPO in the regulation of PLP levels in the cell, which occurs via a feedback inhibition mechanism of the enzyme, exerted by binding of PLP at an allosteric site. Through docking analyses and site-directed mutagenesis experiments, here we identified the allosteric PLP binding site of human PNPO. This site is located in the same protein region as the allosteric site we previously identified in the Escherichia coli enzyme homologue. However, the identity and arrangement of the amino acid residues involved in PLP binding are completely different and resemble those of the active site of PLP-dependent enzymes. The identification of the PLP allosteric site of human PNPO paves the way for the rational design of enzyme inhibitors as potential anti-cancer compounds.
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Affiliation(s)
- Anna Barile
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
| | - Claudio Graziani
- Sapienza Università di RomaIstituto Pasteur Italia‐Fondazione Cenci BolognettiRomeItaly
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Lorenzo Antonelli
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Alessia Parroni
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
| | - Annarita Fiorillo
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Martino Luigi di Salvo
- Sapienza Università di RomaIstituto Pasteur Italia‐Fondazione Cenci BolognettiRomeItaly
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Andrea Ilari
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
| | - Alessandra Giorgi
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Serena Rosignoli
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Alessandro Paiardini
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Roberto Contestabile
- Sapienza Università di RomaIstituto Pasteur Italia‐Fondazione Cenci BolognettiRomeItaly
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Angela Tramonti
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
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Ciapaite J, van Roermund CWT, Bosma M, Gerrits J, Houten SM, IJlst L, Waterham HR, van Karnebeek CDM, Wanders RJA, Zwartkruis FJT, Jans JJ, Verhoeven-Duif NM. Maintenance of cellular vitamin B 6 levels and mitochondrial oxidative function depend on pyridoxal 5'-phosphate homeostasis protein. J Biol Chem 2023; 299:105047. [PMID: 37451483 PMCID: PMC10463200 DOI: 10.1016/j.jbc.2023.105047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 06/23/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023] Open
Abstract
Recently, biallelic variants in PLPBP coding for pyridoxal 5'-phosphate homeostasis protein (PLPHP) were identified as a novel cause of early-onset vitamin B6-dependent epilepsy. The molecular function and precise role of PLPHP in vitamin B6 metabolism are not well understood. To address these questions, we used PLPHP-deficient patient skin fibroblasts and HEK293 cells and YBL036C (PLPHP ortholog)-deficient yeast. We showed that independent of extracellular B6 vitamer type (pyridoxine, pyridoxamine, or pyridoxal), intracellular pyridoxal 5'-phosphate (PLP) was lower in PLPHP-deficient fibroblasts and HEK293 cells than controls. Culturing cells with pyridoxine or pyridoxamine led to the concentration-dependent accumulation of pyridoxine 5'-phosphate and pyridoxamine 5'-phosphate (PMP), respectively, suggesting insufficient pyridox(am)ine 5'-phosphate oxidase activity. Experiments utilizing 13C4-pyridoxine confirmed lower pyridox(am)ine 5'-phosphate oxidase activity and revealed increased fractional turnovers of PLP and pyridoxal, indicating increased PLP hydrolysis to pyridoxal in PLPHP-deficient cells. This effect could be partly counteracted by inactivation of pyridoxal phosphatase. PLPHP deficiency had a distinct effect on mitochondrial PLP and PMP, suggesting impaired activity of mitochondrial transaminases. Moreover, in YBL036C-deficient yeast, PLP was depleted and PMP accumulated only with carbon sources requiring mitochondrial metabolism. Lactate and pyruvate accumulation along with the decrease of tricarboxylic acid cycle intermediates downstream of α-ketoglutarate suggested impaired mitochondrial oxidative metabolism in PLPHP-deficient HEK293 cells. We hypothesize that impaired activity of mitochondrial transaminases may contribute to this depletion. Taken together, our study provides new insights into the pathomechanisms of PLPBP deficiency and reinforces the link between PLPHP function, vitamin B6 metabolism, and mitochondrial oxidative metabolism.
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Affiliation(s)
- Jolita Ciapaite
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands; United for Metabolic Diseases, The Netherlands.
| | - Carlo W T van Roermund
- United for Metabolic Diseases, The Netherlands; Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology & Metabolism, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, The Netherlands
| | - Marjolein Bosma
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands; United for Metabolic Diseases, The Netherlands
| | - Johan Gerrits
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands; United for Metabolic Diseases, The Netherlands
| | - Sander M Houten
- Department of Genetics and Genomic Sciences, Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Lodewijk IJlst
- United for Metabolic Diseases, The Netherlands; Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology & Metabolism, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, The Netherlands
| | - Hans R Waterham
- United for Metabolic Diseases, The Netherlands; Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology & Metabolism, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, The Netherlands
| | - Clara D M van Karnebeek
- United for Metabolic Diseases, The Netherlands; Departments of Pediatrics and Human Genetics, Emma Center for Personalized Medicine, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, The Netherlands; Department of Pediatrics, Centre for Molecular Medicine and Therapeutics, BC Children's Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ronald J A Wanders
- United for Metabolic Diseases, The Netherlands; Laboratory Genetic Metabolic Diseases, Amsterdam Gastroenterology & Metabolism, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, The Netherlands
| | - Fried J T Zwartkruis
- Department of Molecular Cancer Research, Center for Molecular Medicine, Oncode Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Judith J Jans
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands; United for Metabolic Diseases, The Netherlands
| | - Nanda M Verhoeven-Duif
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands; United for Metabolic Diseases, The Netherlands
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5
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Abstract
A survey of protein databases indicates that the majority of enzymes exist in oligomeric forms, with about half of those found in the UniProt database being homodimeric. Understanding why many enzymes are in their dimeric form is imperative. Recent developments in experimental and computational techniques have allowed for a deeper comprehension of the cooperative interactions between the subunits of dimeric enzymes. This review aims to succinctly summarize these recent advancements by providing an overview of experimental and theoretical methods, as well as an understanding of cooperativity in substrate binding and the molecular mechanisms of cooperative catalysis within homodimeric enzymes. Focus is set upon the beneficial effects of dimerization and cooperative catalysis. These advancements not only provide essential case studies and theoretical support for comprehending dimeric enzyme catalysis but also serve as a foundation for designing highly efficient catalysts, such as dimeric organic catalysts. Moreover, these developments have significant implications for drug design, as exemplified by Paxlovid, which was designed for the homodimeric main protease of SARS-CoV-2.
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Affiliation(s)
- Ke-Wei Chen
- Lab of Computional Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Tian-Yu Sun
- Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Yun-Dong Wu
- Lab of Computional Chemistry and Drug Design, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
- Shenzhen Bay Laboratory, Shenzhen 518132, China
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6
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Aleshin VA, Bunik VI. Protein-Protein Interfaces as Druggable Targets: A Common Motif of the Pyridoxal-5'-Phosphate-Dependent Enzymes to Receive the Coenzyme from Its Producers. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1022-1033. [PMID: 37751871 DOI: 10.1134/s0006297923070131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/22/2023] [Accepted: 04/10/2023] [Indexed: 09/28/2023]
Abstract
Pyridoxal-5'-phosphate (PLP), a phosphorylated form of vitamin B6, acts as a coenzyme for numerous reactions, including those changed in cancer and/or associated with the disease prognosis. Since highly reactive PLP can modify cellular proteins, it is hypothesized to be directly transferred from its donors to acceptors. Our goal is to validate the hypothesis by finding common motif(s) in the multitude of PLP-dependent enzymes for binding the limited number of PLP donors, namely pyridoxal kinase (PdxK), pyridox(am)in-5'-phosphate oxidase (PNPO), and PLP-binding protein (PLPBP). Experimentally confirmed interactions between the PLP donors and acceptors reveal that PdxK and PNPO interact with the most abundant PLP acceptors belonging to structural folds I and II, while PLPBP - with those belonging to folds III and V. Aligning sequences and 3D structures of the identified interactors of PdxK and PNPO, we have identified a common motif in the PLP-dependent enzymes of folds I and II. The motif extends from the enzyme surface to the neighborhood of the PLP binding site, represented by an exposed alfa-helix, a partially buried beta-strand, and residual loops. Pathogenicity of mutations in the human PLP-dependent enzymes within or in the vicinity of the motif, but outside of the active sites, supports functional significance of the motif that may provide an interface for the direct transfer of PLP from the sites of its synthesis to those of coenzyme binding. The enzyme-specific amino acid residues of the common motif may be useful to develop selective inhibitors blocking PLP delivery to the PLP-dependent enzymes critical for proliferation of malignant cells.
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Affiliation(s)
- Vasily A Aleshin
- Department of Biokinetics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Department of Biochemistry, Sechenov University, Moscow, 119048, Russia
| | - Victoria I Bunik
- Department of Biokinetics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
- Department of Biochemistry, Sechenov University, Moscow, 119048, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
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Rivero M, Boneta S, Novo N, Velázquez-Campoy A, Polo V, Medina M. Riboflavin kinase and pyridoxine 5′-phosphate oxidase complex formation envisages transient interactions for FMN cofactor delivery. Front Mol Biosci 2023; 10:1167348. [PMID: 37056721 PMCID: PMC10086132 DOI: 10.3389/fmolb.2023.1167348] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
Enzymes catalysing sequential reactions have developed different mechanisms to control the transport and flux of reactants and intermediates along metabolic pathways, which usually involve direct transfer of metabolites from an enzyme to the next one in a cascade reaction. Despite the fact that metabolite or substrate channelling has been widely studied for reactant molecules, such information is seldom available for cofactors in general, and for flavins in particular. Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) act as cofactors in flavoproteins and flavoenzymes involved in a wide range of physiologically relevant processes in all type of organisms. Homo sapiens riboflavin kinase (RFK) catalyses the biosynthesis of the flavin mononucleotide cofactor, and might directly interplay with its flavin client apo-proteins prior to the cofactor transfer. Non-etheless, none of such complexes has been characterized at molecular or atomic level so far. Here, we particularly evaluate the interaction of riboflavin kinase with one of its potential FMN clients, pyridoxine-5′-phosphate oxidase (PNPOx). The interaction capacity of both proteins is assessed by using isothermal titration calorimetry, a methodology that allows to determine dissociation constants for interaction in the micromolar range (in agreement with the expected transient nature of the interaction). Moreover, we show that; i) both proteins become thermally stabilized upon mutual interaction, ii) the tightly bound FMN product can be transferred from RFK to the apo-form of PNPOx producing an efficient enzyme, and iii) the presence of the apo-form of PNPOx slightly enhances RFK catalytic efficiency. Finally, we also show a computational study to predict likely RFK-PNPOx binding modes that can envisage coupling between the FMN binding cavities of both proteins for the potential transfer of FMN.
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Affiliation(s)
- Maribel Rivero
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Zaragoza, Spain
| | - Sergio Boneta
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Zaragoza, Spain
| | - Nerea Novo
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Zaragoza, Spain
| | - Adrián Velázquez-Campoy
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), Madrid, Spain
- Group of Biochemistry, Biophysics and Computational Biology “GBsC” (BIFI, Unizar) Joint Unit to CSIC, Zaragoza, Spain
| | - Victor Polo
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Zaragoza, Spain
- Departamento de Química Física, Universidad de Zaragoza, Zaragoza, Spain
| | - Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, Zaragoza, Spain
- Group of Biochemistry, Biophysics and Computational Biology “GBsC” (BIFI, Unizar) Joint Unit to CSIC, Zaragoza, Spain
- *Correspondence: Milagros Medina,
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Makwana P, Hungund SP, Pradeep ANR. Dipteran endoparasitoid Exorista bombycis utilizes antihemocyte components against host defense of silkworm Bombyx mori. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2023; 112:e21976. [PMID: 36205611 DOI: 10.1002/arch.21976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/07/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
Dipteran endoparasitoids avoid host immune response; however, antidefense components from the Dipterans are unknown. Infestation of commercial silkworm Bombyx mori Linnaeus (Lepidoptera: Bombycidae) by endoparasitoid Exorista bombycis Louis (Diptera: Tachinidae) induced immune reactions, cytotoxicity, granulation, degranulation, and augmented release of cytotoxic marker enzyme lactate dehydrogenase (LDH), and degranulation-mediator enzyme β-hexosaminidase in hemocytes. In this study, by reverse phase high-performance liquid chromatography, fractions of E. bombycis larval tissue protein with antihemocytic activity are separated. From the fraction, peptides of hemocyte aggregation inhibitor protein (HAIP) and pyridoxamine phosphate oxidase (PNPO) are identified by mass spectrometry. Interacting partners of HAIP and PNPO are retrieved that further enhance the virulence of the parasitoid. PNPO and HAIP genes showed a four- to seven fold increase in expression in the integument of the parasitoid larva. Together, the dipteran endoparasitoid E. bombycis exploit antihemocyte activity to inhibit host defense reactions in addition to defense evasion contemplated.
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Affiliation(s)
- Pooja Makwana
- Seribiotech Research Laboratory, CSB-Kodathi Campus, Bangalore, Karnataka, India
- Biotechnology Division, Central Sericultural Research & Training Institute, Berhampore, West Bengal, India
| | - Shambhavi P Hungund
- Seribiotech Research Laboratory, CSB-Kodathi Campus, Bangalore, Karnataka, India
| | - Appukuttan Nair R Pradeep
- Seribiotech Research Laboratory, CSB-Kodathi Campus, Bangalore, Karnataka, India
- Biotechnology Division, Central Sericultural Research & Training Institute, Berhampore, West Bengal, India
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9
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Elucidating the Interaction between Pyridoxine 5'-Phosphate Oxidase and Dopa Decarboxylase: Activation of B6-Dependent Enzyme. Int J Mol Sci 2022; 24:ijms24010642. [PMID: 36614085 PMCID: PMC9820991 DOI: 10.3390/ijms24010642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/22/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
Pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, serves as a cofactor for scores of B6-dependent (PLP-dependent) enzymes involved in many cellular processes. One such B6 enzyme is dopa decarboxylase (DDC), which is required for the biosynthesis of key neurotransmitters, e.g., dopamine and serotonin. PLP-dependent enzymes are biosynthesized as apo-B6 enzymes and then converted to the catalytically active holo-B6 enzymes by Schiff base formation between the aldehyde of PLP and an active site lysine of the protein. In eukaryotes, PLP is made available to the B6 enzymes through the activity of the B6-salvage enzymes, pyridoxine 5'-phosphate oxidase (PNPO) and pyridoxal kinase (PLK). To minimize toxicity, the cell keeps the content of free PLP (unbound) very low through dephosphorylation and PLP feedback inhibition of PNPO and PLK. This has led to a proposed mechanism of complex formation between the B6-salvage enzymes and apo-B6 enzymes prior to the transfer of PLP, although such complexes are yet to be characterized at the atomic level, presumably due to their transient nature. A computational study, for the first time, was used to predict a likely PNPO and DDC complex, which suggested contact between the allosteric PLP tight-binding site on PNPO and the active site of DDC. Using isothermal calorimetry and/or surface plasmon resonance, we also show that PNPO binds both apoDDC and holoDDC with dissociation constants of 0.93 ± 0.07 μM and 2.59 ± 0.11 μM, respectively. Finally, in the presence of apoDDC, the tightly bound PLP on PNPO is transferred to apoDDC, resulting in the formation of about 35% holoDDC.
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10
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Machover D, Goldschmidt E, Almohamad W, Castagné V, Dairou J, Desterke C, Gomez L, Gaston-Mathé Y, Boucheix C. Pharmacologic modulation of 5-fluorouracil by folinic acid and pyridoxine for treatment of patients with advanced breast carcinoma. Sci Rep 2022; 12:9079. [PMID: 35641554 PMCID: PMC9156777 DOI: 10.1038/s41598-022-12998-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 05/12/2022] [Indexed: 11/24/2022] Open
Abstract
High concentration pyridoxal 5’-phosphate, the cofactor of vitamin B6, potentiates cytotoxicity in cancer cells exposed to 5-fluorouracil (FUra) and folinic acid (FA). We studied the effect of high-dose pyridoxine on antitumor activity of regimens comprising FUra and FA in 27 advanced breast carcinoma patients. Of 18 previously untreated patients, 12 had tumors that did not overexpress HER2 (Group I), and 6 that overexpressed HER2 (Group II). Nine patients (Group III) had prior chemotherapy. Group I received AVCF (doxorubicin, vinorelbine, cyclophosphamide, FUra, FA) or FAC (doxorubicin, cyclophosphamide, FUra, FA) followed by TCbF (paclitaxel carboplatin, FUra, FA). Groups II, and III received TCbF. Pyridoxine iv (1000–3000 mg/day) preceded each FA and FUra. Group II also received trastuzumab and pertuzumab. 26 patients responded. Three patients in Group I had CRs and 9 had PRs with 62–98% reduction rates; 4 patients in Group II had CRs and 2 had PRs with 98% reduction. Of 7 measurable patients in Group III, 2 attained CRs, and 5 had PRs with 81–94% reduction rates. Median time to response was 3.4 months. Unexpected toxicity did not occur. This pilot study suggests that high-dose vitamin B6 enhances antitumor potency of regimens comprising FUra and FA.
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Affiliation(s)
- David Machover
- INSERM U935-UA09 and Institut de Cancérologie et d'Immunogénétique (ICIG), Paul-Brousse Hospital, University Paris-Saclay, 12, Avenue Paul-Vaillant-Couturier, 94800, Villejuif, France.
| | - Emma Goldschmidt
- Department of Medical Oncology, Paul-Brousse Hospital, Assistance Publique-Hôpitaux de Paris (APHP), University Paris-Saclay, 94800, Villejuif, France
| | - Wathek Almohamad
- Department of Medical Oncology, Paul-Brousse Hospital, Assistance Publique-Hôpitaux de Paris (APHP), University Paris-Saclay, 94800, Villejuif, France
| | - Vincent Castagné
- Department of Pharmacy, Paul-Brousse Hospital, APHP, University Paris-Saclay, 94800, Villejuif, France
| | - Julien Dairou
- Laboratory of Pharmacologic Biochemistry and Toxicology, CNRS UMR 8601, University Paris-Descartes, 45, Rue des Saints-Pères, 75006, Paris, France
| | - Christophe Desterke
- INSERM U935-UA09 and Institut de Cancérologie et d'Immunogénétique (ICIG), Paul-Brousse Hospital, University Paris-Saclay, 12, Avenue Paul-Vaillant-Couturier, 94800, Villejuif, France
| | - Léa Gomez
- Department of Biophysics and Nuclear Medicine, Kremlin-Bicêtre Hospital, APHP, University Paris-Saclay, 94270, Le Kremlin-Bicêtre, France
| | | | - Claude Boucheix
- INSERM U935-UA09 and Institut de Cancérologie et d'Immunogénétique (ICIG), Paul-Brousse Hospital, University Paris-Saclay, 12, Avenue Paul-Vaillant-Couturier, 94800, Villejuif, France
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11
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Drosophila carrying epilepsy-associated variants in the vitamin B6 metabolism gene PNPO display allele- and diet-dependent phenotypes. Proc Natl Acad Sci U S A 2022; 119:2115524119. [PMID: 35217610 PMCID: PMC8892510 DOI: 10.1073/pnas.2115524119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2022] [Indexed: 12/02/2022] Open
Abstract
Both genetic and environmental factors contribute to epilepsy. Understanding their contributions and interactions helps disease management. However, it is often challenging to study gene–environment interaction in humans due to their heterogeneous genetic background and less controllable environmental factors. The fruit fly, Drosophila melanogaster, has been proven to be a powerful model to study human diseases, including epilepsy. We generated knock-in flies carrying different epilepsy-associated pyridox(am)ine 5′-phosphate oxidase (PNPO) alleles and studied the developmental, behavioral, electrophysiological, and fitness effects of each mutant allele under different dietary conditions. We showed that phenotypes in knock-in flies are allele and diet dependent, providing clues for timely and specific diet interventions. Our results offer biological insights into mechanisms underlying phenotypic variations and specific therapeutic strategies. Pyridox(am)ine 5′-phosphate oxidase (PNPO) catalyzes the rate-limiting step in the synthesis of pyridoxal 5′-phosphate (PLP), the active form of vitamin B6 required for the synthesis of neurotransmitters gamma-aminobutyric acid (GABA) and the monoamines. Pathogenic variants in PNPO have been increasingly identified in patients with neonatal epileptic encephalopathy and early-onset epilepsy. These patients often exhibit different types of seizures and variable comorbidities. Recently, the PNPO gene has also been implicated in epilepsy in adults. It is unclear how these phenotypic variations are linked to specific PNPO alleles and to what degree diet can modify their expression. Using CRISPR-Cas9, we generated four knock-in Drosophila alleles, hWT, hR116Q, hD33V , and hR95H, in which the endogenous Drosophila PNPO was replaced by wild-type human PNPO complementary DNA (cDNA) and three epilepsy-associated variants. We found that these knock-in flies exhibited a wide range of phenotypes, including developmental impairments, abnormal locomotor activities, spontaneous seizures, and shortened life span. These phenotypes are allele dependent, varying with the known biochemical severity of these mutations and our characterized molecular defects. We also showed that diet treatments further diversified the phenotypes among alleles, and PLP supplementation at larval and adult stages prevented developmental impairments and seizures in adult flies, respectively. Furthermore, we found that hR95H had a significant dominant-negative effect, rendering heterozygous flies susceptible to seizures and premature death. Together, these results provide biological bases for the various phenotypes resulting from multifunction of PNPO, specific molecular and/or genetic properties of each PNPO variant, and differential allele–diet interactions.
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12
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Characterization of Novel Pathogenic Variants Causing Pyridox(am)ine 5'-Phosphate Oxidase-Dependent Epilepsy. Int J Mol Sci 2021; 22:ijms222112013. [PMID: 34769443 PMCID: PMC8584306 DOI: 10.3390/ijms222112013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 11/17/2022] Open
Abstract
Several variants of the enzyme pyridox(am)ine 5′-phosphate oxidase (PNPO), responsible for a rare form of vitamin B6-dependent neonatal epileptic encephalopathy known as PNPO deficiency (PNPOD), have been reported. However, only a few of them have been characterised with respect to their structural and functional properties, despite the fact that the knowledge of how variants affect the enzyme may clarify the disease mechanism and improve treatment. Here, we report the characterisation of the catalytic, allosteric and structural properties of recombinantly expressed D33V, R161C, P213S, and E50K variants, among which D33V (present in approximately 10% of affected patients) is one of the more common variants responsible for PNPOD. The D33V and E50K variants have only mildly altered catalytic properties. In particular, the E50K variant, given that it has been found on the same chromosome with other known pathogenic variants, may be considered non-pathogenic. The P213S variant has lower thermal stability and reduced capability to bind the FMN cofactor. The variant involving Arg161 (R161C) largely decreases the affinity for the pyridoxine 5′-phosphate substrate and completely abolishes the allosteric feedback inhibition exerted by the pyridoxal 5′-phosphate product.
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13
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Hadtstein F, Vrolijk M. Vitamin B-6-Induced Neuropathy: Exploring the Mechanisms of Pyridoxine Toxicity. Adv Nutr 2021; 12:1911-1929. [PMID: 33912895 PMCID: PMC8483950 DOI: 10.1093/advances/nmab033] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 12/26/2022] Open
Abstract
Vitamin B-6 in the form of pyridoxine (PN) is commonly used by the general population. The use of PN-containing supplements has gained lots of attention over the past years as they have been related to the development of peripheral neuropathy. In light of this, the number of reported cases of adverse health effects due to the use of vitamin B-6 have increased. Despite a long history of study, the pathogenic mechanisms associated with PN toxicity remain elusive. Therefore, the present review is focused on investigating the mechanistic link between PN supplementation and sensory peripheral neuropathy. Excessive PN intake induces neuropathy through the preferential injury of sensory neurons. Recent reports on hereditary neuropathy due to pyridoxal kinase (PDXK) mutations may provide some insight into the mechanism, as genetic deficiencies in PDXK lead to the development of axonal sensory neuropathy. High circulating concentrations of PN may lead to a similar condition via the inhibition of PDXK. The mechanism behind PDXK-induced neuropathy is unknown; however, there is reason to believe that it may be related to γ-aminobutyric acid (GABA) neurotransmission. Compounds that inhibit PDXK lead to convulsions and reductions in GABA biosynthesis. The absence of central nervous system-related symptoms in PDXK deficiency could be due to differences in the regulation of PDXK, where PDXK activity is preserved in the brain but not in peripheral tissues. As PN is relatively impermeable to the blood-brain barrier, PDXK inhibition would similarly be confined to the peripheries and, as a result, GABA signaling may be perturbed within peripheral tissues, such as sensory neurons. Perturbed GABA signaling within sensory neurons may lead to excitotoxicity, neurodegeneration, and ultimately, the development of peripheral neuropathy. For several reasons, we conclude that PDXK inhibition and consequently disrupted GABA neurotransmission is the most plausible mechanism of toxicity.
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Affiliation(s)
- Felix Hadtstein
- University College Venlo, Campus Venlo, Maastricht University, Maastricht, The Netherlands
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14
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Abstract
Vitamin B6 is an ensemble of six interconvertible vitamers: pyridoxine (PN), pyridoxamine (PM), pyridoxal (PL), and their 5'-phosphate derivatives, PNP, PMP, and PLP. Pyridoxal 5'-phosphate is a coenzyme in a variety of enzyme reactions concerning transformations of amino and amino acid compounds. This review summarizes all known and putative PLP-binding proteins found in the Escherichia coli MG1655 proteome. PLP can have toxic effects since it contains a very reactive aldehyde group at its 4' position that easily forms aldimines with primary and secondary amines and reacts with thiols. Most PLP is bound either to the enzymes that use it as a cofactor or to PLP carrier proteins, protected from the cellular environment but at the same time readily transferable to PLP-dependent apoenzymes. E. coli and its relatives synthesize PLP through the seven-step deoxyxylulose-5-phosphate (DXP)-dependent pathway. Other bacteria synthesize PLP in a single step, through a so-called DXP-independent pathway. Although the DXP-dependent pathway was the first to be revealed, the discovery of the widespread DXP-independent pathway determined a decline of interest in E. coli vitamin B6 metabolism. In E. coli, as in most organisms, PLP can also be obtained from PL, PN, and PM, imported from the environment or recycled from protein turnover, via a salvage pathway. Our review deals with all aspects of vitamin B6 metabolism in E. coli, from transcriptional to posttranslational regulation. A critical interpretation of results is presented, in particular, concerning the most obscure aspects of PLP homeostasis and delivery to PLP-dependent enzymes.
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15
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Ghatge MS, Al Mughram M, Omar AM, Safo MK. Inborn errors in the vitamin B6 salvage enzymes associated with neonatal epileptic encephalopathy and other pathologies. Biochimie 2021; 183:18-29. [PMID: 33421502 PMCID: PMC11273822 DOI: 10.1016/j.biochi.2020.12.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/28/2022]
Abstract
Pyridoxal 5'-phosphate (PLP), the active cofactor form of vitamin B6 is required by over 160 PLP-dependent (vitamin B6) enzymes serving diverse biological roles, such as carbohydrates, amino acids, hemes, and neurotransmitters metabolism. Three key enzymes, pyridoxal kinase (PL kinase), pyridoxine 5'-phosphate oxidase (PNPO), and phosphatases metabolize and supply PLP to PLP-dependent enzymes through the salvage pathway. In born errors in the salvage enzymes are known to cause inadequate levels of PLP in the cell, particularly in neuronal cells. The resulting PLP deficiency is known to cause or implicated in several pathologies, most notably seizures. One such disorder, PNPO-dependent neonatal epileptic encephalopathy (NEE) results from natural mutations in PNPO and leads to null or reduced enzymatic activity. NEE does not respond to conventional antiepileptic drugs but may respond to treatment with the B6 vitamers PLP and/or pyridoxine (PN). In born errors that lead to PLP deficiency in cells have also been reported in PL kinase, however, to date none has been associated with epilepsy or seizure. One such pathology is polyneuropathy that responds to PLP therapy. Phosphatase deficiency or hypophosphatasia disorder due to pathogenic mutations in alkaline phosphatase is known to cause seizures that respond to PN therapy. In this article, we review the biochemical features of in born errors pertaining to the salvage enzyme's deficiency that leads to NEE and other pathologies. We also present perspective on vitamin B6 treatment for these disorders, along with attempts to develop zebrafish model to study the NEE syndrome in vivo.
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Affiliation(s)
- Mohini S Ghatge
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Mohammed Al Mughram
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Abdelsattar M Omar
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Alsulaymanyah, Jeddah, 21589, Saudi Arabia; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Al-Azhar University, Cairo, 11884, Egypt
| | - Martin K Safo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA.
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16
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Turnšek J, Brunson JK, Viedma MDPM, Deerinck TJ, Horák A, Oborník M, Bielinski VA, Allen AE. Proximity proteomics in a marine diatom reveals a putative cell surface-to-chloroplast iron trafficking pathway. eLife 2021; 10:e52770. [PMID: 33591270 PMCID: PMC7972479 DOI: 10.7554/elife.52770] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/15/2021] [Indexed: 12/16/2022] Open
Abstract
Iron is a biochemically critical metal cofactor in enzymes involved in photosynthesis, cellular respiration, nitrate assimilation, nitrogen fixation, and reactive oxygen species defense. Marine microeukaryotes have evolved a phytotransferrin-based iron uptake system to cope with iron scarcity, a major factor limiting primary productivity in the global ocean. Diatom phytotransferrin is endocytosed; however, proteins downstream of this environmentally ubiquitous iron receptor are unknown. We applied engineered ascorbate peroxidase APEX2-based subcellular proteomics to catalog proximal proteins of phytotransferrin in the model marine diatom Phaeodactylum tricornutum. Proteins encoded by poorly characterized iron-sensitive genes were identified including three that are expressed from a chromosomal gene cluster. Two of them showed unambiguous colocalization with phytotransferrin adjacent to the chloroplast. Further phylogenetic, domain, and biochemical analyses suggest their involvement in intracellular iron processing. Proximity proteomics holds enormous potential to glean new insights into iron acquisition pathways and beyond in these evolutionarily, ecologically, and biotechnologically important microalgae.
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Affiliation(s)
- Jernej Turnšek
- Biological and Biomedical Sciences, The Graduate School of Arts and Sciences, Harvard UniversityCambridgeUnited States
- Department of Systems Biology, Harvard Medical SchoolBostonUnited States
- Wyss Institute for Biologically Inspired Engineering, Harvard UniversityBostonUnited States
- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California San DiegoLa JollaUnited States
- Center for Research in Biological Systems, University of California San DiegoLa JollaUnited States
- Microbial and Environmental Genomics, J. Craig Venter InstituteLa JollaUnited States
| | - John K Brunson
- Microbial and Environmental Genomics, J. Craig Venter InstituteLa JollaUnited States
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San DiegoLa JollaUnited States
| | | | - Thomas J Deerinck
- National Center for Microscopy and Imaging Research, University of California San DiegoLa JollaUnited States
| | - Aleš Horák
- Biology Centre CAS, Institute of ParasitologyČeské BudějoviceCzech Republic
- University of South Bohemia, Faculty of ScienceČeské BudějoviceCzech Republic
| | - Miroslav Oborník
- Biology Centre CAS, Institute of ParasitologyČeské BudějoviceCzech Republic
- University of South Bohemia, Faculty of ScienceČeské BudějoviceCzech Republic
| | - Vincent A Bielinski
- Synthetic Biology and Bioenergy, J. Craig Venter InstituteLa JollaUnited States
| | - Andrew Ellis Allen
- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California San DiegoLa JollaUnited States
- Microbial and Environmental Genomics, J. Craig Venter InstituteLa JollaUnited States
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17
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Da’dara AA, Elzoheiry M, El-Beshbishi SN, Skelly PJ. Vitamin B6 Acquisition and Metabolism in Schistosoma mansoni. Front Immunol 2021; 11:622162. [PMID: 33613557 PMCID: PMC7891054 DOI: 10.3389/fimmu.2020.622162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/17/2020] [Indexed: 11/13/2022] Open
Abstract
Schistosomes are parasitic platyhelminths that currently infect >200 million people globally. The adult worms can live within the vasculature of their hosts for many years where they acquire all nutrients necessary for their survival and growth. In this work we focus on how Schistosoma mansoni parasites acquire and metabolize vitamin B6, whose active form is pyridoxal phosphate (PLP). We show here that live intravascular stage parasites (schistosomula and adult males and females) can cleave exogenous PLP to liberate pyridoxal. Of the three characterized nucleotide-metabolizing ectoenzymes expressed at the schistosome surface (SmAP, SmNPP5, and SmATPDase1), only SmAP hydrolyzes PLP. Heat-inactivated recombinant SmAP can no longer cleave PLP. Further, parasites whose SmAP gene has been suppressed by RNAi are significantly impaired in their ability to cleave PLP compared to controls. When schistosomes are incubated in murine plasma, they alter its metabolomic profile-the levels of both pyridoxal and phosphate increase over time, a finding consistent with the action of host-exposed SmAP acting on PLP. We hypothesize that SmAP-mediated dephosphorylation of PLP generates a pool of pyridoxal around the worms that can be conveniently taken in by the parasites to participate in essential, vitamin B6-driven metabolism. In addition, since host PLP-dependent enzymes play active roles in inflammatory processes, parasite-mediated cleavage of this metabolite may serve to limit parasite-damaging inflammation. In this work we also identified schistosome homologs of enzymes that are involved in intracellular vitamin B6 metabolism. These are pyridoxal kinase (SmPK) as well as pyridoxal phosphate phosphatase (SmPLP-Ph) and pyridox(am)ine 5'-phosphate oxidase (SmPNPO) and cDNAs encoding these three enzymes were cloned and sequenced. The three genes encoding these enzymes all display high relative expression in schistosomula and adult worms suggestive of robust vitamin B6 metabolism in the intravascular life stages.
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Affiliation(s)
- Akram A. Da’dara
- Molecular Helminthology Laboratory, Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, United States
| | - Manal Elzoheiry
- Molecular Helminthology Laboratory, Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, United States
- Department of Medical Parasitology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Samar N. El-Beshbishi
- Department of Medical Parasitology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Patrick J. Skelly
- Molecular Helminthology Laboratory, Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA, United States
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18
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Boyko AI, Artiukhov AV, Kaehne T, di Salvo ML, Bonaccorsi di Patti MC, Contestabile R, Tramonti A, Bunik VI. Isoforms of the DHTKD1-Encoded 2-Oxoadipate Dehydrogenase, Identified in Animal Tissues, Are not Observed upon the Human DHTKD1 Expression in Bacterial or Yeast Systems. BIOCHEMISTRY (MOSCOW) 2021; 85:920-929. [PMID: 33045952 DOI: 10.1134/s0006297920080076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Unlike the OGDH-encoded 2-oxoglutarate dehydrogenase (OGDH), which is an essential enzyme present in all animal tissues, expression of the DHTKD1-encoded isoenzyme, 2-oxoadipate dehydrogenase (OADH), depends on a number of factors, and mutant DHTKD1 phenotypes are rarely manifested. Physiological significance of OADH is also obscured by the fact that both isoenzymes transform 2-oxoglutarate and 2-oxoadipate. By analogy with other members of the 2-oxo acid dehydrogenases family, OADH is assumed to be a component of the multienzyme complex that catalyzes oxidative decarboxylation of 2-oxoadipate. This study aims at molecular characterization of OADH from animal tissues. Phylogenetic analysis of 2-oxo acid dehydrogenases reveals OADH only in animals and Dictyostelium discoideum slime mold, within a common branch with bacterial OGDH. Examination of partially purified animal OADH by immunoblotting and mass spectrometry identifies two OADH isoforms with molecular weights of about 130 and 70 kDa. These isoforms are not observed upon the expression of human DHTKD1 protein in either bacterial or yeast system, where the synthesized OADH is of expected molecular weight (about 100 kDa). Thus, the OADH isoforms present in animal tissues, may result from the animal-specific regulation of the DHTKD1 expression and/or posttranslational modifications of the encoded protein. Mapping of the peptides identified in the OADH preparations, onto the protein structure suggests that the 70-kDa isoform is truncated at the N-terminus, but retains the active site. Since the N-terminal domain of OGDH is required for the formation of the multienzyme complex, it is possible that the 70-kDa isoform catalyzes non-oxidative transformation of dicarboxylic 2-oxo acids that does not require the multienzyme structure. In this case, the ratio of the OADH isoforms in animal tissues may correspond to the ratio between the oxidative and non-oxidative decarboxylation of 2-oxoadipate.
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Affiliation(s)
- A I Boyko
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia.
| | - A V Artiukhov
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - T Kaehne
- Institute of Experimental Internal Medicine, Otto-von-Guericke University, Magdeburg, 39120, Germany
| | - M L di Salvo
- Department of Biological Sciences A. Rossi Fanelli, Sapienza University, Rome, 00185, Italy
| | | | - R Contestabile
- Department of Biological Sciences A. Rossi Fanelli, Sapienza University, Rome, 00185, Italy
| | - A Tramonti
- Department of Biological Sciences A. Rossi Fanelli, Sapienza University, Rome, 00185, Italy.,Institute of Molecular Biology and Pathology, Council of National Research, Rome, 00185, Italy
| | - V I Bunik
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia. .,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.,Department of Biological Chemistry, Sechenov First Moscow State Medical University, Moscow, 119146, Russia
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19
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Brunet Avalos C, Sprecher SG. Single-Cell Transcriptomic Reveals Dual and Multi-Transmitter Use in Neurons Across Metazoans. Front Mol Neurosci 2021; 14:623148. [PMID: 33597849 PMCID: PMC7883486 DOI: 10.3389/fnmol.2021.623148] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/07/2021] [Indexed: 11/17/2022] Open
Abstract
Neurotransmitter expression is widely used as a criterion for classifying neurons. It was initially thought that neurons express a single type of neurotransmitter, a phenomenon commonly recognized as Dale's principle: “one neuron, one transmitter.” Consequently, the expression of a single neurotransmitter should determine stable and distinguishable neuronal characteristics. However, this notion has been largely challenged and increasing evidence accumulates supporting a different scenario: “one neuron, multiple neurotransmitters.” Single-cell transcriptomics provides an additional path to address coexpression of neurotransmitters, by investigating the expression of genes involved in the biosynthesis and transmission of fast-acting neuromodulators. Here, we study neuronal phenotypes based on the expression of neurotransmitters, at single-cell resolution, across different animal species representing distinct clades of the tree of life. We take advantage of several existing scRNAseq datasets and analyze them in light of neurotransmitter plasticity. Our results show that while most neurons appear to predominantly express a single type of neurotransmitter, a substantial number of neurons simultaneously expresses a combination of them, across all animal species analyzed.
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Affiliation(s)
| | - Simon G Sprecher
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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20
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Alghamdi M, Bashiri FA, Abdelhakim M, Adly N, Jamjoom DZ, Sumaily KM, Alghanem B, Arold ST. Phenotypic and molecular spectrum of pyridoxamine-5'-phosphate oxidase deficiency: A scoping review of 87 cases of pyridoxamine-5'-phosphate oxidase deficiency. Clin Genet 2020; 99:99-110. [PMID: 32888189 PMCID: PMC7820968 DOI: 10.1111/cge.13843] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 12/29/2022]
Abstract
Pyridoxamine-5'-phosphate oxidase (PNPO) deficiency is an autosomal recessive pyridoxal 5'-phosphate (PLP)-vitamin-responsive epileptic encephalopathy. The emerging feature of PNPO deficiency is the occurrence of refractory seizures in the first year of life. Pre-maturity and fetal distress, combined with neonatal seizures, are other associated key characteristics. The phenotype results from a dependency of PLP which regulates several enzymes in the body. We present the phenotypic and genotypic spectrum of (PNPO) deficiency based on a literature review (2002-2020) of reports (n = 33) of patients with confirmed PNPO deficiency (n = 87). All patients who received PLP (n = 36) showed a clinical response, with a complete dramatic PLP response with seizure cessation observed in 61% of patients. In spite of effective seizure control with PLP, approximately 56% of patients affected with PLP-dependent epilepsy suffer developmental delay/intellectual disability. There is no diagnostic biomarker, and molecular testing required for diagnosis. However, we noted that cerebrospinal fluid (CSF) PLP was low in 81%, CSF glycine was high in 80% and urinary vanillactic acid was high in 91% of the cases. We observed only a weak correlation between the severity of PNPO protein disruption and disease outcomes, indicating the importance of other factors, including seizure onset and time of therapy initiation. We found that pre-maturity, the delay in initiation of PLP therapy and early onset of seizures correlate with a poor neurocognitive outcome. Given the amenability of PNPO to PLP therapy for seizure control, early diagnosis is essential.
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Affiliation(s)
- Malak Alghamdi
- Medical Genetics Division, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Fahad A Bashiri
- Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia.,Neurology division, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Marwa Abdelhakim
- Computer, Electrical and Mathematical Science and Engineering Division (CEMSE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Nouran Adly
- College of Medicine Research Center, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Dima Z Jamjoom
- Department of Radiology and Medical Imaging, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Khalid M Sumaily
- Clinical Biochemistry Unit, Department of Laboratory Medicine, King Saud University Medical City, King Saud University, Riyadh, Saudi Arabia
| | - Bandar Alghanem
- Medical Research Core Facility and Platforms (MRCFP), King Abdullah International Medical, Research Center/King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), King, Abdulaziz Medical City (KAMC), NGHA, Riyadh, Saudi Arabia
| | - Stefan T Arold
- Computational Bioscience, Research Center (CBRC); Division of Biological and Environmental Sciences and Engineering, (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, Montpellier, France
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21
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Barile A, Nogués I, di Salvo ML, Bunik V, Contestabile R, Tramonti A. Molecular characterization of pyridoxine 5'-phosphate oxidase and its pathogenic forms associated with neonatal epileptic encephalopathy. Sci Rep 2020; 10:13621. [PMID: 32788630 PMCID: PMC7424515 DOI: 10.1038/s41598-020-70598-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/31/2020] [Indexed: 01/18/2023] Open
Abstract
Defects of vitamin B6 metabolism are responsible for severe neurological disorders, such as pyridoxamine 5'-phosphate oxidase deficiency (PNPOD; OMIM: 610090), an autosomal recessive inborn error of metabolism that usually manifests with neonatal-onset severe seizures and subsequent encephalopathy. At present, 27 pathogenic mutations of the gene encoding human PNPO are known, 13 of which are homozygous missense mutations; however, only 3 of them have been characterised with respect to the molecular and functional properties of the variant enzyme forms. Moreover, studies on wild type and variant human PNPOs have so far largely ignored the regulation properties of this enzyme. Here, we present a detailed characterisation of the inhibition mechanism of PNPO by pyridoxal 5'-phosphate (PLP), the reaction product of the enzyme. Our study reveals that human PNPO has an allosteric PLP binding site that plays a crucial role in the enzyme regulation and therefore in the regulation of vitamin B6 metabolism in humans. Furthermore, we have produced, recombinantly expressed and characterised several PNPO pathogenic variants responsible for PNPOD (G118R, R141C, R225H, R116Q/R225H, and X262Q). Such replacements mainly affect the catalytic activity of PNPO and binding of the enzyme substrate and FMN cofactor, leaving the allosteric properties unaltered.
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Affiliation(s)
- Anna Barile
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy.,Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Isabel Nogués
- Istituto di Ricerca sugli Ecosistemi Terrestri, Consiglio Nazionale delle Ricerche, 00015, Monterotondo, Rome, Italy
| | - Martino L di Salvo
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Victoria Bunik
- Belozersky Institute of Physico-Chemical Biology, Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119991, Russia.,Department of Biochemistry, Sechenov University, Trubetskaya, 8/2, Moscow, 119991, Russia
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy.
| | - Angela Tramonti
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy. .,Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy.
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22
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Pyridoxamine-phosphate oxidases and pyridoxamine-phosphate oxidase-related proteins catalyze the oxidation of 6-NAD(P)H to NAD(P). Biochem J 2020; 476:3033-3052. [PMID: 31657440 DOI: 10.1042/bcj20190602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/30/2019] [Accepted: 10/03/2019] [Indexed: 11/17/2022]
Abstract
6-NADH and 6-NADPH are strong inhibitors of several dehydrogenases that may form spontaneously from NAD(P)H. They are known to be oxidized to NAD(P)+ by mammalian renalase, an FAD-linked enzyme mainly present in heart and kidney, and by related bacterial enzymes. We partially purified an enzyme oxidizing 6-NADPH from rat liver, and, surprisingly, identified it as pyridoxamine-phosphate oxidase (PNPO). This was confirmed by the finding that recombinant mouse PNPO oxidized 6-NADH and 6-NADPH with catalytic efficiencies comparable to those observed with pyridoxine- and pyridoxamine-5'-phosphate. PNPOs from Escherichia coli, Saccharomyces cerevisiae and Arabidopsis thaliana also displayed 6-NAD(P)H oxidase activity, indicating that this 'side-activity' is conserved. Remarkably, 'pyridoxamine-phosphate oxidase-related proteins' (PNPO-RP) from Nostoc punctiforme, A. thaliana and the yeast S. cerevisiae (Ygr017w) were not detectably active on pyridox(am)ine-5'-P, but oxidized 6-NADH, 6-NADPH and 2-NADH suggesting that this may be their main catalytic function. Their specificity profiles were therefore similar to that of renalase. Inactivation of renalase and of PNPO in mammalian cells and of Ygr017w in yeasts led to the accumulation of a reduced form of 6-NADH, tentatively identified as 4,5,6-NADH3, which can also be produced in vitro by reduction of 6-NADH by glyceraldehyde-3-phosphate dehydrogenase or glucose-6-phosphate dehydrogenase. As 4,5,6-NADH3 is not a substrate for renalase, PNPO or PNPO-RP, its accumulation presumably reflects the block in the oxidation of 6-NADH. These findings indicate that two different classes of enzymes using either FAD (renalase) or FMN (PNPOs and PNPO-RPs) as a cofactor play an as yet unsuspected role in removing damaged forms of NAD(P).
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23
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Chi W, Iyengar ASR, Albersen M, Bosma M, Verhoeven-Duif NM, Wu CF, Zhuang X. Pyridox (am) ine 5'-phosphate oxidase deficiency induces seizures in Drosophila melanogaster. Hum Mol Genet 2020; 28:3126-3136. [PMID: 31261385 DOI: 10.1093/hmg/ddz143] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/12/2022] Open
Abstract
Pyridox (am) ine 5'-phosphate oxidase (PNPO) is a rate-limiting enzyme in converting dietary vitamin B6 (VB6) to pyridoxal 5'-phosphate (PLP), the biologically active form of VB6 and involved in the synthesis of neurotransmitters including γ-aminobutyric acid (GABA), dopamine, and serotonin. In humans, PNPO mutations have been increasingly identified in neonatal epileptic encephalopathy and more recently also in early-onset epilepsy. Till now, little is known about the neurobiological mechanisms underlying PNPO-deficiency-induced seizures due to the lack of animal models. Previously, we identified a c.95 C>A missense mutation in sugarlethal (sgll)-the Drosophila homolog of human PNPO (hPNPO)-and found mutant (sgll95) flies exhibiting a lethal phenotype on a diet devoid of VB6. Here, we report the establishment of both sgll95 and ubiquitous sgll knockdown (KD) flies as valid animal models of PNPO-deficiency-induced epilepsy. Both sgll95 and sgll KD flies exhibit spontaneous seizures before they die. Electrophysiological recordings reveal that seizures caused by PNPO deficiency have characteristics similar to that in flies treated with the GABA antagonist picrotoxin. Both seizures and lethality are associated with low PLP levels and can be rescued by ubiquitous expression of wild-type sgll or hPNPO, suggesting the functional conservation of the PNPO enzyme between humans and flies. Results from cell type-specific sgll KD further demonstrate that PNPO in the brain is necessary for seizure prevention and survival. Our establishment of the first animal model of PNPO deficiency will lead to better understanding of VB6 biology, the PNPO gene and its mutations discovered in patients, and can be a cost-effective system to test therapeutic strategies.
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Affiliation(s)
- Wanhao Chi
- Committee on Genetics, Genomics and Systems Biology.,Department of Neurobiology, University of Chicago, Chicago, IL, USA
| | - Atulya S R Iyengar
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA, USA
| | - Monique Albersen
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Marjolein Bosma
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Nanda M Verhoeven-Duif
- Section Metabolic Diagnostics, Department of Medical Genetics, University Medical Center Utrecht, Utrecht, EA, The Netherlands
| | - Chun-Fang Wu
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA, USA
| | - Xiaoxi Zhuang
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
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24
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Chen PY, Tu HC, Schirch V, Safo MK, Fu TF. Pyridoxamine Supplementation Effectively Reverses the Abnormal Phenotypes of Zebrafish Larvae With PNPO Deficiency. Front Pharmacol 2019; 10:1086. [PMID: 31616300 PMCID: PMC6764245 DOI: 10.3389/fphar.2019.01086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 08/26/2019] [Indexed: 01/09/2023] Open
Abstract
Neonatal epileptic encephalopathy (NEE), as a result of pyridoxine 5′-phosphate oxidase (PNPO) deficiency, is a rare neural disorder characterized by intractable seizures and usually leads to early infant death. The clinical phenotypes do not respond to antiepileptic drugs but are alleviated in most cases by giving large doses of pyridoxal 5′-phosphate (PLP). PLP is the active form of vitamin B6 participating in more than 100 enzymatic pathways. One of the causes of NEE is pathogenic mutations in the gene for human PNPO (hPNPO). PNPO is a key enzyme in converting pyridoxine (PN), the common dietary form of vitamin B6, and some other B6 vitamers to PLP. More than 25 different mutations in hPNPO, which result in reduced catalytic activity, have been described for PNPO-deficiency NEE. To date, no animal model is available to test new therapeutic strategies. In this report, we describe using zebrafish with reduced activity of Pnpo as an animal model. Knocking down zPnpo resulted in developmental anomalies including brain malformation and impaired locomotor activity, similar to the clinical features of PNPO-deficiency NEE. Other anomalies include a defective circulation system. These anomalies were significantly alleviated by co-injecting either zpnpo or hPNPO mRNAs. As expected from clinical observations in humans, supplementing with PLP improved the morphological and behavioral anomalies. PN only showed marginal positive effects, and only in a few anomalies. Remarkably, pyridoxamine (PM), another dietary form of vitamin B6, showed rescue effects even at a lower concentration than PLP, presenting a possible new therapeutic treatment for PNPO-deficiency NEE. Finally, GABA, a neurotransmitter whose biosynthesis depends on a PLP-dependent enzyme, showed some positive rescue effect. These results suggest zebrafish to be a promising PNPO-deficiency model for studying PLP homeostasis and drug therapy in vivo.
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Affiliation(s)
- Po-Yuan Chen
- College of Medicine, Institute of Basic Medical Science, National Cheng Kung University, Tainan, Taiwan
| | - Hung-Chi Tu
- College of Medicine, Institute of Basic Medical Science, National Cheng Kung University, Tainan, Taiwan
| | - Verne Schirch
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, United States
| | - Martin K Safo
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, United States
| | - Tzu-Fun Fu
- College of Medicine, Institute of Basic Medical Science, National Cheng Kung University, Tainan, Taiwan.,Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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25
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Barile A, Tramonti A, di Salvo ML, Nogués I, Nardella C, Malatesta F, Contestabile R. Allosteric feedback inhibition of pyridoxine 5'-phosphate oxidase from Escherichia coli. J Biol Chem 2019; 294:15593-15603. [PMID: 31484724 DOI: 10.1074/jbc.ra119.009697] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/02/2019] [Indexed: 11/06/2022] Open
Abstract
In Escherichia coli, the synthesis of pyridoxal 5'-phosphate (PLP), the catalytically active form of vitamin B6, takes place through the so-called deoxyxylulose 5-phosphate-dependent pathway, whose last step is pyridoxine 5'-phosphate (PNP) oxidation to PLP, catalyzed by the FMN-dependent enzyme PNP oxidase (PNPOx). This enzyme plays a pivotal role in controlling intracellular homeostasis and bioavailability of PLP. PNPOx has been proposed to undergo product inhibition resulting from PLP binding at the active site. PLP has also been reported to bind tightly at a secondary site, apparently without causing PNPOx inhibition. The possible location of this secondary site has been indicated by crystallographic studies as two symmetric surface pockets present on the PNPOx homodimer, but this site has never been verified by other experimental means. Here, we demonstrate, through kinetic measurements, that PLP inhibition is actually of a mixed-type nature and results from binding of this vitamer at an allosteric site. This interpretation was confirmed by the characterization of a mutated PNPOx form, in which substrate binding at the active site is heavily hampered but PLP binding is preserved. Structural and functional connections between the active site and the allosteric site were indicated by equilibrium binding experiments, which revealed different PLP-binding stoichiometries with WT and mutant PNPOx forms. These observations open up new horizons on the mechanisms that regulate E. coli PNPOx, which may have commonalities with the mechanisms regulating human PNPOx, whose crucial role in vitamin B6 metabolism and epilepsy is well-known.
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Affiliation(s)
- Anna Barile
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli," Sapienza Università di Roma, Laboratory affiliated with Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Angela Tramonti
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli," Sapienza Università di Roma, Laboratory affiliated with Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Piazzale Aldo Moro 5, 00185 Roma, Italy.,Istituto di Biologia e Patologia Molecolari, CNR, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Martino Luigi di Salvo
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli," Sapienza Università di Roma, Laboratory affiliated with Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Isabel Nogués
- Istituto di Ricerca sugli Ecosistemi Terrestri, CNR, Via G. Marconi 2, 05010 Porano (TR), Italy
| | - Caterina Nardella
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli," Sapienza Università di Roma, Laboratory affiliated with Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Francesco Malatesta
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli," Sapienza Università di Roma, Laboratory affiliated with Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli," Sapienza Università di Roma, Laboratory affiliated with Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Piazzale Aldo Moro 5, 00185 Roma, Italy
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26
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Loohuis LM, Albersen M, de Jong S, Wu T, Luykx JJ, Jans JJM, Verhoeven-Duif NM, Ophoff RA. The Alkaline Phosphatase (ALPL) Locus Is Associated with B6 Vitamer Levels in CSF and Plasma. Genes (Basel) 2018; 10:genes10010008. [PMID: 30583557 PMCID: PMC6357176 DOI: 10.3390/genes10010008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 01/27/2023] Open
Abstract
The active form of vitamin B6, pyridoxal phosphate (PLP), is essential for human metabolism. The brain is dependent on vitamin B6 for its neurotransmitter balance. To obtain insight into the genetic determinants of vitamin B6 homeostasis, we conducted a genome-wide association study (GWAS) of the B6 vitamers pyridoxal (PL), PLP and the degradation product of vitamin B6, pyridoxic acid (PA). We collected a unique sample set of cerebrospinal fluid (CSF) and plasma from the same healthy human subjects of Dutch ancestry (n = 493) and included concentrations and ratios in and between these body fluids in our analysis. Based on a multivariate joint analysis of all B6 vitamers and their ratios, we identified a genome-wide significant association at a locus on chromosome 1 containing the ALPL (alkaline phosphatase) gene (minimal p = 7.89 × 10−10, rs1106357, minor allele frequency (MAF) = 0.46), previously associated with vitamin B6 levels in blood. Subjects homozygous for the minor allele showed a 1.4-times-higher ratio between PLP and PL in plasma, and even a 1.6-times-higher ratio between PLP and PL in CSF than subjects homozygous for the major allele. In addition, we observed a suggestive association with the CSF:plasma ratio of PLP on chromosome 15 (minimal p = 7.93 × 10−7, and MAF = 0.06 for rs28789220). Even though this finding is not reaching genome-wide significance, it highlights the potential of our experimental setup for studying transport and metabolism across the blood–CSF barrier. This GWAS of B6 vitamers identifies alkaline phosphatase as a key regulator in human vitamin B6 metabolism in CSF as well as plasma. Furthermore, our results demonstrate the potential of genetic studies of metabolites in plasma and CSF to elucidate biological aspects underlying metabolite generation, transport and degradation.
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Affiliation(s)
- Loes M Loohuis
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles (UCLA), Los Angeles, CA 90095, USA.
| | - Monique Albersen
- Section Metabolic Diagnostics, Department of Genetics, University Medical Center (UMC), 3584 EA, Utrecht, The Netherlands.
| | - Simone de Jong
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles (UCLA), Los Angeles, CA 90095, USA.
| | - Timothy Wu
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles (UCLA), Los Angeles, CA 90095, USA.
| | - Jurjen J Luykx
- Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center (UMC), 3584 CG, Utrecht, The Netherlands.
- Department of Translational Neuroscience, Human Neurogenetics Unit, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMC), 3584 CG, Utrecht, The Netherlands.
| | - Judith J M Jans
- Section Metabolic Diagnostics, Department of Genetics, University Medical Center (UMC), 3584 EA, Utrecht, The Netherlands.
| | - Nanda M Verhoeven-Duif
- Section Metabolic Diagnostics, Department of Genetics, University Medical Center (UMC), 3584 EA, Utrecht, The Netherlands.
| | - Roel A Ophoff
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles (UCLA), Los Angeles, CA 90095, USA.
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27
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Functional identification of the proximal promoter region of human pyridoxine 5′-phosphate oxidase gene. GENE REPORTS 2018. [DOI: 10.1016/j.genrep.2018.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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28
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Parra M, Stahl S, Hellmann H. Vitamin B₆ and Its Role in Cell Metabolism and Physiology. Cells 2018; 7:cells7070084. [PMID: 30037155 PMCID: PMC6071262 DOI: 10.3390/cells7070084] [Citation(s) in RCA: 195] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 12/11/2022] Open
Abstract
Vitamin B6 is one of the most central molecules in cells of living organisms. It is a critical co-factor for a diverse range of biochemical reactions that regulate basic cellular metabolism, which impact overall physiology. In the last several years, major progress has been accomplished on various aspects of vitamin B6 biology. Consequently, this review goes beyond the classical role of vitamin B6 as a cofactor to highlight new structural and regulatory information that further defines how the vitamin is synthesized and controlled in the cell. We also discuss broader applications of the vitamin related to human health, pathogen resistance, and abiotic stress tolerance. Overall, the information assembled shall provide helpful insight on top of what is currently known about the vitamin, along with addressing currently open questions in the field to highlight possible approaches vitamin B6 research may take in the future.
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Affiliation(s)
- Marcelina Parra
- Hellmann Lab, School of Biological Sciences, College of Liberal Arts and Sciences, Washington State University, Pullman, 99164-6234 WA, USA.
| | - Seth Stahl
- Hellmann Lab, School of Biological Sciences, College of Liberal Arts and Sciences, Washington State University, Pullman, 99164-6234 WA, USA.
| | - Hanjo Hellmann
- Hellmann Lab, School of Biological Sciences, College of Liberal Arts and Sciences, Washington State University, Pullman, 99164-6234 WA, USA.
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29
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di Salvo ML, Mastrangelo M, Nogués I, Tolve M, Paiardini A, Carducci C, Mei D, Montomoli M, Tramonti A, Guerrini R, Contestabile R, Leuzzi V. Biochemical data from the characterization of a new pathogenic mutation of human pyridoxine-5'-phosphate oxidase (PNPO). Data Brief 2017; 15:868-875. [PMID: 29379851 PMCID: PMC5779537 DOI: 10.1016/j.dib.2017.10.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/07/2017] [Accepted: 10/12/2017] [Indexed: 02/04/2023] Open
Abstract
PNPO deficiency is responsible of severe neonatal encephalopathy, responsive to pyridoxal-5′-phosphate (PLP) or pyridoxine. Recent studies widened the phenotype of this condition and detected new genetic variants on PNPO gene, whose pathogenetic role and clinical expression remain to be established. One of these mutations, Arg116Gln, is of particular interest because of its later onset of symptoms (beyond the first months of life) and its peculiar epileptic manifestations in patients. This protein variant was expressed as recombinant protein in E coli, purified to homogeneity, and characterized with respect to structural and kinetic properties, stability, binding constants of cofactor flavin mononucleotide (FMN) and product (PLP) in order to define the molecular and structural bases of its pathogenicity. For interpretation and discussion of reported data, together with the description of clinical studies, refer to the article [1] (doi: 10.1016/j.ymgme.2017.08.003).
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Affiliation(s)
- Martino L. di Salvo
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza Università di Roma, Italy
| | - Mario Mastrangelo
- Dipartimento di Pediatria e Neuropsichiatria Infantile, Sapienza Università di Roma, Via dei Sabelli 108, 00141 Roma, Italy
| | - Isabel Nogués
- Istituto di Biologia Ambientale e Forestale, Consiglio Nazionale delle Ricerche, Monterotondo Scalo, Roma, Italy
| | - Manuela Tolve
- Dipartimento di Medicina Sperimentale, Sapienza Università di Roma, Italy
| | - Alessandro Paiardini
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Sapienza Università di Roma, Italy
| | - Carla Carducci
- Dipartimento di Medicina Sperimentale, Sapienza Università di Roma, Italy
| | - Davide Mei
- Dipartimento di Neuroscienze, Azienda Ospedaliero-Universitaria Meyer, Università di Firenze, Italy
| | - Martino Montomoli
- Dipartimento di Neuroscienze, Azienda Ospedaliero-Universitaria Meyer, Università di Firenze, Italy
| | - Angela Tramonti
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Roma, Italy
| | - Renzo Guerrini
- Dipartimento di Neuroscienze, Azienda Ospedaliero-Universitaria Meyer, Università di Firenze, Italy
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”, Sapienza Università di Roma, Italy
| | - Vincenzo Leuzzi
- Dipartimento di Pediatria e Neuropsichiatria Infantile, Sapienza Università di Roma, Via dei Sabelli 108, 00141 Roma, Italy
- Corresponding author. Fax: +39 064440232.
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30
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di Salvo ML, Mastrangelo M, Nogués I, Tolve M, Paiardini A, Carducci C, Mei D, Montomoli M, Tramonti A, Guerrini R, Contestabile R, Leuzzi V. Pyridoxine-5'-phosphate oxidase (Pnpo) deficiency: Clinical and biochemical alterations associated with the C.347g>A (P.·Arg116gln) mutation. Mol Genet Metab 2017; 122:135-142. [PMID: 28818555 DOI: 10.1016/j.ymgme.2017.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 11/19/2022]
Abstract
BACKGROUND Pyridoxal-5'-phosphate oxidase (PNPO) deficiency presents as a severe neonatal encephalopathy responsive to pyridoxal-5'-phosphate (PLP) or pyridoxine. Recent studies widened the phenotype of this condition and detected genetic variants on PNPO gene whose pathogenic role and clinical expression remain to be established. OBJECTIVE This paper aims to characterize the functional effects of the c.347G>A (p.Arg116Gln) mutation in the PNPO gene in order to define its pathogenicity and describe the clinical features of new patients with epilepsy carrying this mutation. METHODS Arg116Gln protein variant was expressed as recombinant protein. The mutant protein was characterized with respect to structural and kinetic properties, thermal stability, binding constants of cofactor (FMN) and product (PLP). We also reviewed clinical data of 3 new patients carrying the mutation. RESULTS The Arg116Gln mutation does not alter the overall enzyme structure and only slightly affects its catalytic efficiency; nevertheless, this mutation affects thermal stability of PNPO, reduces its affinity for FMN and impairs transfer of PLP to PLP-dependent enzymes. Three boys with seizure onset between 8months and 3years of age, carrying the Arg116Gln mutation, are described. These three patients exhibited different seizure types associated with interictal EEG abnormalities and slow background activity. Mild/moderate intellectual disability was observed in 2/3 patients. A dramatic therapeutic response to pyridoxine was observed in the only patient who still had active seizures when starting treatment, while in all three patients interictal EEG discharges and background activity improved after pyridoxine treatment was initiated. CONCLUSIONS The reported data support a pathogenic role of the c.347G>A (p.Arg116Gln) mutation in PNPO deficiency. The later onset of symptoms and the milder epilepsy phenotype of these expand the disease phenotype.
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Affiliation(s)
- Martino L di Salvo
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Italy.
| | - Mario Mastrangelo
- Dipartimento di Pediatria e Neuropsichiatria Infantile, Sapienza Università di Roma, Italy.
| | - Isabel Nogués
- Istituto di Biologia Ambientale e Forestale, Consiglio Nazionale delle Ricerche, Monterotondo Scalo, Roma, Italy.
| | - Manuela Tolve
- Dipartimento di Medicina Sperimentale, Sapienza Università di Roma, Italy
| | - Alessandro Paiardini
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, Italy.
| | - Carla Carducci
- Dipartimento di Medicina Sperimentale, Sapienza Università di Roma, Italy.
| | - Davide Mei
- Dipartimento di Neuroscienze, Azienda Ospedaliero-Universitaria Meyer, Università di Firenze, Italy.
| | - Martino Montomoli
- Dipartimento di Neuroscienze, Azienda Ospedaliero-Universitaria Meyer, Università di Firenze, Italy.
| | - Angela Tramonti
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Roma, Italy.
| | - Renzo Guerrini
- Dipartimento di Neuroscienze, Azienda Ospedaliero-Universitaria Meyer, Università di Firenze, Italy.
| | - Roberto Contestabile
- Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Italy.
| | - Vincenzo Leuzzi
- Dipartimento di Pediatria e Neuropsichiatria Infantile, Sapienza Università di Roma, Italy.
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31
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Hacker SM, Backus KM, Lazear MR, Forli S, Correia BE, Cravatt BF. Global profiling of lysine reactivity and ligandability in the human proteome. Nat Chem 2017; 9:1181-1190. [PMID: 29168484 DOI: 10.1038/nchem.2826] [Citation(s) in RCA: 283] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 06/07/2017] [Indexed: 12/28/2022]
Abstract
Nucleophilic amino acids make important contributions to protein function, including performing key roles in catalysis and serving as sites for post-translational modification. Electrophilic groups that target amino-acid nucleophiles have been used to create covalent ligands and drugs, but have, so far, been mainly limited to cysteine and serine. Here, we report a chemical proteomic platform for the global and quantitative analysis of lysine residues in native biological systems. We have quantified, in total, more than 9,000 lysines in human cell proteomes and have identified several hundred residues with heightened reactivity that are enriched at protein functional sites and can frequently be targeted by electrophilic small molecules. We have also discovered lysine-reactive fragment electrophiles that inhibit enzymes by active site and allosteric mechanisms, as well as disrupt protein-protein interactions in transcriptional regulatory complexes, emphasizing the broad potential and diverse functional consequences of liganding lysine residues throughout the human proteome.
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Affiliation(s)
- Stephan M Hacker
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92307, USA
| | - Keriann M Backus
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92307, USA
| | - Michael R Lazear
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92307, USA
| | - Stefano Forli
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92307, USA
| | - Bruno E Correia
- Laboratory of Protein Design & Immunoengineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Benjamin F Cravatt
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92307, USA
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32
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Rapid determination of the various native forms of vitamin B 6 and B 2 in cow's milk using ultra-high performance liquid chromatography. J Chromatogr A 2017; 1500:89-95. [PMID: 28420530 DOI: 10.1016/j.chroma.2017.04.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/05/2017] [Accepted: 04/07/2017] [Indexed: 11/22/2022]
Abstract
As the formation of pyridoxal phosphate, the active cofactor of vitamin B6, is dependent on riboflavin 5-phosphate, we propose a fast and simple ultra-high performance liquid chromatography method for the simultaneous determination of the native B6 vitamers pyridoxal, pyridoxine, pyridoxamine, their mono phosphorus esters and 4-pyridoxic acid as well as vitamin B2 as riboflavin and its phosphorus ester riboflavin 5-phosphate in milk. Separation was achieved under 6.0min by reversed-phase and pH gradient elution. Sample preparation was optimized regarding various acids and pH levels. Changes in those parameters led to significant deviations of sample matrix breakdown efficiency. The optimized method was then validated regarding specificity, accuracy, precision, linearity, range, detection and quantification limits. As the method performed satisfactory, is was used to study commercial liquid cow's milk (n=31), regarding effects of the employed preservation technique (pasteurization, extended shelf-life, ultra-high temperature) on the composition and content of B6 and B2 vitamers. In cow's milk, vitamin B6 mostly consists of pyridoxal and its phosphate ester, with pyridoxal phosphate being the bulk component. The catabolite of the vitamin B6 metabolism, 4-pyridoxic acid was present in significant amounts in all studied samples, with up to 2.69μmolL-1. Vitamin B2 was present as riboflavin and its phosphate ester up to 12.86μmolL-1.
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33
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Mohamed-Ahmed AHA, Wilson MP, Albuera M, Chen T, Mills PB, Footitt EJ, Clayton PT, Tuleu C. Quality and stability of extemporaneous pyridoxal phosphate preparations used in the treatment of paediatric epilepsy. J Pharm Pharmacol 2017; 69:480-488. [DOI: 10.1111/jphp.12701] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 01/12/2017] [Indexed: 11/29/2022]
Abstract
Abstract
Objectives
To assess the pyridoxal 5′-phosphate (PLP) content and stability of extemporaneous PLP liquids prepared from dietary supplements used for the treatment of vitamin B6-dependent epilepsy.
Methods
Pyridoxal 5′-phosphate liquids were prepared in accordance with the guidelines given to patients from marketed 50 mg PLP dietary capsules and tablets. The PLP content and its stability were evaluated under conditions resembling the clinical setting using reverse phase HPLC and mass spectrometry.
Key findings
Pyridoxal 5′-phosphate content in most of the extemporaneously prepared liquids from dietary supplements was found to be different from the expected amount (~16–60 mg). Most of these PLP extemporaneous liquids were stable at room temperature (protected from light) after 24 h but unstable after 4 h when exposed to light. A key photodegradation product of PLP in water was confirmed as 4-pyridoxic acid 5′-phosphate (PAP).
Conclusion
Pyridoxal 5′-phosphate tablets from Solgar® were found to be the most reliable product for the preparation of extemporaneous PLP liquids. This work highlighted the difference between the marketed PLP dietary supplements quality and the importance of proper storage of aqueous PLP. There is a need to develop pharmaceutical forms of PLP that ensure dose accuracy and avoid potentially unsafe impurities with the aim of enhancing safety and compliance.
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Affiliation(s)
| | - Matthew P Wilson
- Institute of Child Health, University College London, London, UK
| | | | - Ting Chen
- UCL School of Pharmacy, University College London, London, UK
| | - Philippa B Mills
- Institute of Child Health, University College London, London, UK
| | - Emma J Footitt
- Metabolic Medicine Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Peter T Clayton
- Institute of Child Health, University College London, London, UK
| | - Catherine Tuleu
- UCL School of Pharmacy, University College London, London, UK
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34
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Ahmed FH, Mohamed AE, Carr PD, Lee BM, Condic-Jurkic K, O'Mara ML, Jackson CJ. Rv2074 is a novel F420 H2 -dependent biliverdin reductase in Mycobacterium tuberculosis. Protein Sci 2016; 25:1692-709. [PMID: 27364382 DOI: 10.1002/pro.2975] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/29/2016] [Indexed: 12/12/2022]
Abstract
Bilirubin is a potent antioxidant that is produced from the reduction of the heme degradation product biliverdin. In mammalian cells and Cyanobacteria, NADH/NADPH-dependent biliverdin reductases (BVRs) of the Rossmann-fold have been shown to catalyze this reaction. Here, we describe the characterization of Rv2074 from Mycobacterium tuberculosis, which belongs to a structurally and mechanistically distinct family of F420 H2 -dependent BVRs (F-BVRs) that are exclusively found in Actinobacteria. We have solved the crystal structure of Rv2074 bound to its cofactor, F420 , and used this alongside molecular dynamics simulations, site-directed mutagenesis and NMR spectroscopy to elucidate its catalytic mechanism. The production of bilirubin by Rv2074 could exploit the anti-oxidative properties of bilirubin and contribute to the range of immuno-evasive mechanisms that have evolved in M. tuberculosis to allow persistent infection.
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Affiliation(s)
- F Hafna Ahmed
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - A Elaaf Mohamed
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Paul D Carr
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Brendon M Lee
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Karmen Condic-Jurkic
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Megan L O'Mara
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Colin J Jackson
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
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35
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Physiology, Biochemistry, and Applications of F420- and Fo-Dependent Redox Reactions. Microbiol Mol Biol Rev 2016; 80:451-93. [PMID: 27122598 DOI: 10.1128/mmbr.00070-15] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
5-Deazaflavin cofactors enhance the metabolic flexibility of microorganisms by catalyzing a wide range of challenging enzymatic redox reactions. While structurally similar to riboflavin, 5-deazaflavins have distinctive and biologically useful electrochemical and photochemical properties as a result of the substitution of N-5 of the isoalloxazine ring for a carbon. 8-Hydroxy-5-deazaflavin (Fo) appears to be used for a single function: as a light-harvesting chromophore for DNA photolyases across the three domains of life. In contrast, its oligoglutamyl derivative F420 is a taxonomically restricted but functionally versatile cofactor that facilitates many low-potential two-electron redox reactions. It serves as an essential catabolic cofactor in methanogenic, sulfate-reducing, and likely methanotrophic archaea. It also transforms a wide range of exogenous substrates and endogenous metabolites in aerobic actinobacteria, for example mycobacteria and streptomycetes. In this review, we discuss the physiological roles of F420 in microorganisms and the biochemistry of the various oxidoreductases that mediate these roles. Particular focus is placed on the central roles of F420 in methanogenic archaea in processes such as substrate oxidation, C1 pathways, respiration, and oxygen detoxification. We also describe how two F420-dependent oxidoreductase superfamilies mediate many environmentally and medically important reactions in bacteria, including biosynthesis of tetracycline and pyrrolobenzodiazepine antibiotics by streptomycetes, activation of the prodrugs pretomanid and delamanid by Mycobacterium tuberculosis, and degradation of environmental contaminants such as picrate, aflatoxin, and malachite green. The biosynthesis pathways of Fo and F420 are also detailed. We conclude by considering opportunities to exploit deazaflavin-dependent processes in tuberculosis treatment, methane mitigation, bioremediation, and industrial biocatalysis.
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Prunetti L, El Yacoubi B, Schiavon CR, Kirkpatrick E, Huang L, Bailly M, El Badawi-Sidhu M, Harrison K, Gregory JF, Fiehn O, Hanson AD, de Crécy-Lagard V. Evidence that COG0325 proteins are involved in PLP homeostasis. MICROBIOLOGY-SGM 2016; 162:694-706. [PMID: 26872910 DOI: 10.1099/mic.0.000255] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Pyridoxal 5'-phosphate (PLP) is an essential cofactor for nearly 60 Escherichia coli enzymes but is a highly reactive molecule that is toxic in its free form. How PLP levels are regulated and how PLP is delivered to target enzymes are still open questions. The COG0325 protein family belongs to the fold-type III class of PLP enzymes and binds PLP but has no known biochemical activity although it occurs in all kingdoms of life. Various pleiotropic phenotypes of the E. coli COG0325 (yggS) mutant have been reported, some of which were reproduced and extended in this study. Comparative genomic, genetic and metabolic analyses suggest that these phenotypes reflect an imbalance in PLP homeostasis. The E. coli yggS mutant accumulates the PLP precursor pyridoxine 5'-phosphate (PNP) and is sensitive to an excess of pyridoxine but not of pyridoxal. The pyridoxine toxicity phenotype is complemented by the expression of eukaryotic yggS orthologs. It is also suppressed by the presence of amino acids, specifically isoleucine, threonine and leucine, suggesting the PLP-dependent enzyme transaminase B (IlvE) is affected. These genetic results lay a foundation for future biochemical studies of the role of COG0325 proteins in PLP homeostasis.
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Affiliation(s)
- Laurence Prunetti
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Basma El Yacoubi
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Cara R Schiavon
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Ericka Kirkpatrick
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Lili Huang
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL, USA
| | - Marc Bailly
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Mona El Badawi-Sidhu
- Department of Molecular and Cellular Biology & Genome Center, University of California, Davis, CA, USA
| | - Katherine Harrison
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Jesse F Gregory
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL, USA
| | - Oliver Fiehn
- Department of Molecular and Cellular Biology & Genome Center, University of California, Davis, CA, USA
| | - Andrew D Hanson
- Department of Horticultural Sciences, University of Florida, Gainesville, FL, USA
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences and Genetics Institute, University of Florida, Gainesville, FL, USA
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37
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Ghatge MS, Karve SS, David TMS, Ahmed MH, Musayev FN, Cunningham K, Schirch V, Safo MK. Inactive mutants of human pyridoxine 5'-phosphate oxidase: a possible role for a noncatalytic pyridoxal 5'-phosphate tight binding site. FEBS Open Bio 2016; 6:398-408. [PMID: 27419045 PMCID: PMC4856418 DOI: 10.1002/2211-5463.12042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 02/01/2016] [Accepted: 02/04/2016] [Indexed: 11/11/2022] Open
Abstract
Pyridoxal 5'-phosphate (PLP) is a cofactor for many vitamin B6-requiring enzymes that are important for the synthesis of neurotransmitters. Pyridoxine 5'-phosphate oxidase (PNPO) is one of two enzymes that produce PLP. Some 16 known mutations in human PNPO (hPNPO), including R95C and R229W, lead to deficiency of PLP in the cell and have been shown to cause neonatal epileptic encephalopathy (NEE). This disorder has no effective treatment, and is often fatal unless treated with PLP. In this study, we show that R95C hPNPO exhibits a 15-fold reduction in affinity for the FMN cofactor, a 71-fold decrease in affinity for the substrate PNP, a 4.9-fold decrease in specific activity, and a 343-fold reduction in catalytic activity, compared to the wild-type enzyme. We have reported similar findings for R229W hPNPO. This report also shows that wild-type, R95C and R229W hPNPO bind PLP tightly at a noncatalytic site and transfer it to activate an apo-B6 enzyme into the catalytically active holo-form. We also show for the first time that hPNPO forms specific interactions with several B6 enzymes with dissociation constants ranging from 0.3 to 12.3 μm. Our results suggest a possible in vivo role for the tight binding of PLP in hPNPO, whether wild-type or variant, by protecting the very reactive PLP, and transferring this PLP directly to activate apo-B6 enzymes.
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Affiliation(s)
- Mohini S Ghatge
- Department of Medicinal Chemistry School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development Virginia Commonwealth University Richmond VA USA
| | - Sayali S Karve
- Department of Medicinal Chemistry School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development Virginia Commonwealth University Richmond VA USA
| | - Tanya M S David
- Department of Medicinal Chemistry School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development Virginia Commonwealth University Richmond VA USA
| | - Mostafa H Ahmed
- Department of Medicinal Chemistry School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development Virginia Commonwealth University Richmond VA USA
| | - Faik N Musayev
- Department of Medicinal Chemistry School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development Virginia Commonwealth University Richmond VA USA
| | - Kendra Cunningham
- Department of Medicinal Chemistry School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development Virginia Commonwealth University Richmond VA USA
| | - Verne Schirch
- Department of Medicinal Chemistry School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development Virginia Commonwealth University Richmond VA USA
| | - Martin K Safo
- Department of Medicinal Chemistry School of Pharmacy and Institute for Structural Biology, Drug Discovery and Development Virginia Commonwealth University Richmond VA USA
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38
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Jaeger B, Abeling NG, Salomons GS, Struys EA, Simas-Mendes M, Geukers VG, Poll-The BT. Pyridoxine responsive epilepsy caused by a novel homozygous PNPO mutation. Mol Genet Metab Rep 2016; 6:60-3. [PMID: 27014579 PMCID: PMC4789384 DOI: 10.1016/j.ymgmr.2016.01.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/26/2016] [Accepted: 01/26/2016] [Indexed: 12/20/2022] Open
Abstract
We report a patient with anti-epileptic treatment refractory neonatal seizures responsive to pyridoxine. Biochemical analysis revealed normal markers for antiquitin deficiency and also mutation analysis of the ALDH7A1 (Antiquitin) gene was negative. Mutation analysis of the PNPO gene revealed a novel, homozygous, presumed pathogenic mutation (c.481C > T; p.(Arg161Cys)). Measurements of B6 vitamers in a CSF sample after pyridoxine administration revealed elevated pyridoxamine as the only metabolic marker for PNPO deficiency. With pyridoxine monotherapy the patient is seizure free and neurodevelopmental outcome at the age of 14 months is normal.
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Affiliation(s)
- B Jaeger
- Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands
| | - N G Abeling
- Laboratory of Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, The Netherlands
| | - G S Salomons
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, The Netherlands
| | - E A Struys
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, The Netherlands
| | - M Simas-Mendes
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, The Netherlands
| | - V G Geukers
- Pediatric Intensive Care Department, Academic Medical Center, Amsterdam, The Netherlands
| | - B T Poll-The
- Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands
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39
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Huang S, Yang H, Yao L, Zhang J, Huang L. Effect of exogenous hormones on transcription levels of pyridoxal 5'-phosphate biosynthetic enzymes in the silkworm (Bombyx mori). Comp Biochem Physiol B Biochem Mol Biol 2016; 194-195:20-4. [PMID: 26780217 DOI: 10.1016/j.cbpb.2016.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 12/17/2015] [Accepted: 01/06/2016] [Indexed: 11/25/2022]
Abstract
Vitamin B6 includes 6 pyridine derivatives, among which pyridoxal 5'-phosphate is a coenzyme for over 140 enzymes. Animals acquire their vitamin B6 from food. Through a salvage pathway, pyridoxal 5'-phosphate is synthesized from pyridoxal, pyridoxine or pyridoxamine, in a series of reactions catalyzed by pyridoxal kinase and pyridoxine 5'-phosphate oxidase. The regulation of pyridoxal 5'-phospahte biosynthesis and pyridoxal 5'-phospahte homeostasis are at the center of study for vitamin B6 nutrition. How pyridoxal 5'-phosphate biosynthesis is regulated by hormones has not been reported so far. Our previous studies have shown that pyridoxal 5'-phosphate level in silkworm larva displays cyclic developmental changes. In the current study, effects of exogenous juvenile hormone and molting hormone on the transcription level of genes coding for the enzymes involved in the biosynthesis of pyridoxal 5'-phospahte were examined. Results show that pyridoxal kinase and pyridoxine 5'-phosphate oxidase are regulated at the transcription level by development and are responsive to hormones. Molting hormone stimulates the expression of genes coding for pyridoxal kinase and pyridoxine 5'-phosphate oxidase, and juvenile hormone appears to work against molting hormone. Whether pyridoxal 5'-phosphate biosynthesis is regulated by hormones in general is an important issue for further studies.
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Affiliation(s)
- ShuoHao Huang
- School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, People's Republic of China; Center for Cell and Gene Therapy, Takara Bio Inc., Seta 3-4-1, Otsu, Shiga 520-2193, Japan
| | - HuanHuan Yang
- School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, People's Republic of China
| | - LiLi Yao
- School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, People's Republic of China
| | - JianYun Zhang
- School of Foreign Languages, Anhui Agricultural University, Hefei 230036, People's Republic of China
| | - LongQuan Huang
- School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, People's Republic of China.
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40
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Ahmed FH, Carr PD, Lee BM, Afriat-Jurnou L, Mohamed AE, Hong NS, Flanagan J, Taylor MC, Greening C, Jackson CJ. Sequence-Structure-Function Classification of a Catalytically Diverse Oxidoreductase Superfamily in Mycobacteria. J Mol Biol 2015; 427:3554-3571. [PMID: 26434506 DOI: 10.1016/j.jmb.2015.09.021] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/23/2015] [Accepted: 09/24/2015] [Indexed: 12/11/2022]
Abstract
The deazaflavin cofactor F420 enhances the persistence of mycobacteria during hypoxia, oxidative stress, and antibiotic treatment. However, the identities and functions of the mycobacterial enzymes that utilize F420 under these conditions have yet to be resolved. In this work, we used sequence similarity networks to analyze the distribution of the largest F420-dependent protein family in mycobacteria. We show that these enzymes are part of a larger split β-barrel enzyme superfamily (flavin/deazaflavin oxidoreductases, FDORs) that include previously characterized pyridoxamine/pyridoxine-5'-phosphate oxidases and heme oxygenases. We show that these proteins variously utilize F420, flavin mononucleotide, flavin adenine dinucleotide, and heme cofactors. Functional annotation using phylogenetic, structural, and spectroscopic methods revealed their involvement in heme degradation, biliverdin reduction, fatty acid modification, and quinone reduction. Four novel crystal structures show that plasticity in substrate binding pockets and modifications to cofactor binding motifs enabled FDORs to carry out a variety of functions. This systematic classification and analysis provides a framework for further functional analysis of the roles of FDORs in mycobacterial pathogenesis and persistence.
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Affiliation(s)
- F Hafna Ahmed
- Australian National University Research School of Chemistry, Sullivans Creek Road, Acton, ACT 2601, Australia
| | - Paul D Carr
- Australian National University Research School of Chemistry, Sullivans Creek Road, Acton, ACT 2601, Australia
| | - Brendon M Lee
- Australian National University Research School of Chemistry, Sullivans Creek Road, Acton, ACT 2601, Australia
| | - Livnat Afriat-Jurnou
- Australian National University Research School of Chemistry, Sullivans Creek Road, Acton, ACT 2601, Australia
| | - A Elaaf Mohamed
- Australian National University Research School of Chemistry, Sullivans Creek Road, Acton, ACT 2601, Australia
| | - Nan-Sook Hong
- Australian National University Research School of Chemistry, Sullivans Creek Road, Acton, ACT 2601, Australia
| | - Jack Flanagan
- University of Auckland Faculty of Medical and Health Sciences, 85 Park Road, Grafton, Auckland 2013, New Zealand
| | - Matthew C Taylor
- Commonwealth Scientific and Industrial Research Organisation Land and Water Flagship, Clunies Ross Street, Acton, ACT 2060, Australia
| | - Chris Greening
- Commonwealth Scientific and Industrial Research Organisation Land and Water Flagship, Clunies Ross Street, Acton, ACT 2060, Australia
| | - Colin J Jackson
- Australian National University Research School of Chemistry, Sullivans Creek Road, Acton, ACT 2601, Australia.
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41
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Experimental Evidence for a Revision in the Annotation of Putative Pyridoxamine 5'-Phosphate Oxidases P(N/M)P from Fungi. PLoS One 2015; 10:e0136761. [PMID: 26327315 PMCID: PMC4556617 DOI: 10.1371/journal.pone.0136761] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 08/08/2015] [Indexed: 11/19/2022] Open
Abstract
Pyridoxinamine 5'-phosphate oxidases (P(N/M)P oxidases) that bind flavin mononucleotide (FMN) and oxidize pyridoxine 5'-phosphate or pyridoxamine 5'-phosphate to form pyridoxal 5'-phosphate (PLP) are an important class of enzymes that play a central role in cell metabolism. Failure to generate an adequate supply of PLP is very detrimental to most organisms and is often clinically manifested as a neurological disorder in mammals. In this study, we analyzed the function of YLR456W and YPR172W, two homologous genes of unknown function from S. cerevisiae that have been annotated as putative P(N/M)P oxidases based on sequence homology. Different experimental approaches indicated that neither protein catalyzes PLP formation nor binds FMN. On the other hand, our analysis confirmed the enzymatic activity of Pdx3, the S. cerevisiae protein previously implicated in PLP biosynthesis by genetic and structural characterization. After a careful sequence analysis comparing the putative and confirmed P(N/M)P oxidases, we found that the protein domain (PF01243) that led to the YLR456W and YPR172W annotation is a poor indicator of P(N/M)P oxidase activity. We suggest that a combination of two Pfam domains (PF01243 and PF10590) present in Pdx3 and other confirmed P(N/M)P oxidases would be a stronger predictor of this molecular function. This work exemplifies the importance of experimental validation to rectify genome annotation and proposes a revision in the annotation of at least 400 sequences from a wide variety of fungal species that are homologous to YLR456W and are currently misrepresented as putative P(N/M)P oxidases.
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42
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Levtova A, Camuzeaux S, Laberge AM, Allard P, Brunel-Guitton C, Diadori P, Rossignol E, Hyland K, Clayton PT, Mills PB, Mitchell GA. Normal Cerebrospinal Fluid Pyridoxal 5'-Phosphate Level in a PNPO-Deficient Patient with Neonatal-Onset Epileptic Encephalopathy. JIMD Rep 2015; 22:67-75. [PMID: 25762494 DOI: 10.1007/8904_2015_413] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/23/2015] [Accepted: 01/26/2015] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Deficiency of pyridox(am)ine 5'-phosphate oxidase (PNPO, OMIM 610090) is a treatable autosomal recessive inborn error of metabolism. Neonatal epileptic encephalopathy and a low cerebrospinal fluid (CSF) pyridoxal 5'-phosphate level are the reported hallmarks of PNPO deficiency, but its clinical and biochemical spectra are not fully known. CASE PRESENTATION A girl born at 33 3/7 weeks of gestation developed seizures in the first hours of life. Her seizures initially responded to GABAergic agonists, but she subsequently developed a severe epileptic encephalopathy. Brain MRI and infectious and metabolic evaluations at birth, including urinary alpha-aminoadipic semialdehyde (AASA), were normal. Lumbar puncture at age 3 months showed: pyridoxal 5'-phosphate, 52 nmol/L (normal, 23-64); homovanillic acid, 392 nmol/L (normal, 450-1,132); 5-hydroxyindoleacetic acid, 341 nmol/L (normal, 179-711); and 3-ortho-methyldopa, 30 nmol/L (normal, below 300). The patient was not being treated with pyridoxine nor with pyridoxal 5'-phosphate at the time of the lumbar puncture. She died at age 14 months. A sequencing panel targeting 53 epilepsy-related genes revealed a homozygous missense mutation in PNPO (c.674G>A, p.R225H). Homozygosity was confirmed by parental testing. Expression studies of mutant p.R225H PNPO revealed greatly reduced activity. In conclusion, a normal CSF level of pyridoxal 5'-phosphate does not rule out PNPO deficiency.
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Affiliation(s)
- Alina Levtova
- Divisions of Medical Genetics (AL, AML, CBG, GM) and Neurology (PD, ER), Department of Paediatrics, Biochemical Genetics Laboratory (CBG, PA), CHU Sainte-Justine and Université de Montréal, 3175 Côte-Sainte-Catherine, Montreal, QC, Canada, H3T 1C5
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Mashalidis EH, Gittis AG, Tomczak A, Abell C, Barry CE, Garboczi DN. Molecular insights into the binding of coenzyme F420 to the conserved protein Rv1155 from Mycobacterium tuberculosis. Protein Sci 2015; 24:729-40. [PMID: 25644473 DOI: 10.1002/pro.2645] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 01/17/2015] [Accepted: 01/20/2015] [Indexed: 01/01/2023]
Abstract
Coenzyme F420 is a deazaflavin hydride carrier with a lower reduction potential than most flavins. In Mycobacterium tuberculosis (Mtb), F420 plays an important role in activating PA-824, an antituberculosis drug currently used in clinical trials. Although F420 is important to Mtb redox metabolism, little is known about the enzymes that bind F420 and the reactions that they catalyze. We have identified a novel F420 -binding protein, Rv1155, which is annotated in the Mtb genome sequence as a putative flavin mononucleotide (FMN)-binding protein. Using biophysical techniques, we have demonstrated that instead of binding FMN or other flavins, Rv1155 binds coenzyme F420 . The crystal structure of the complex of Rv1155 and F420 reveals one F420 molecule bound to each monomer of the Rv1155 dimer. Structural, biophysical, and bioinformatic analyses of the Rv1155-F420 complex provide clues about its role in the bacterium.
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Affiliation(s)
- Ellene H Mashalidis
- Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, 20892; Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom
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A nutritional conditional lethal mutant due to pyridoxine 5'-phosphate oxidase deficiency in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2014; 4:1147-54. [PMID: 24739647 PMCID: PMC4065258 DOI: 10.1534/g3.114.011130] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The concept of auxotrophic complementation has been proposed as an approach to identify genes in essential metabolic pathways in Drosophila melanogaster. However, it has achieved limited success to date, possibly due to the low probability of finding mutations fit with the chemically defined profile. Instead of using the chemically defined culture media lacking specific nutrients, we used bare minimum culture medium, i.e., 4% sucrose, for adult Drosophila. We identified a nutritional conditional lethal mutant and localized a c.95C > A mutation in the Drosophila pyridoxine 5'-phosphate oxidase gene [dPNPO or sugarlethal (sgll)] using meiotic recombination mapping, deficiency mapping, and whole genome sequencing. PNPO converts dietary vitamin B6 such as pyridoxine to its active form pyridoxal 5'-phosphate (PLP). The missense mutation (sgll(95)) results in the substitution of alanine to aspartate (p.Ala32Asp). The sgll(95) flies survive well on complete medium but all die within 6 d on 4% sucrose only diet, which can be rescued by pyridoxine or PLP supplement, suggesting that the mutation does not cause the complete loss of PNPO activity. The sgll knockdown further confirms its function as the Drosophila PNPO. Because better tools for positional cloning and cheaper whole genome sequencing have made the identification of point mutations much easier than before, alleviating the necessity to pinpoint specific metabolic pathways before gene identification, we propose that nutritional conditional screens based on bare minimum growth media like ours represent promising approaches for discovering important genes and mutations in metabolic pathways, thereby accelerating the establishment of in vivo models that recapitulate human metabolic diseases.
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Colinas M, Shaw HV, Loubéry S, Kaufmann M, Moulin M, Fitzpatrick TB. A pathway for repair of NAD(P)H in plants. J Biol Chem 2014; 289:14692-706. [PMID: 24706747 DOI: 10.1074/jbc.m114.556092] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Unwanted enzyme side reactions and spontaneous decomposition of metabolites can lead to a build-up of compounds that compete with natural enzyme substrates and must be dealt with for efficient metabolism. It has recently been realized that there are enzymes that process such compounds, formulating the concept of metabolite repair. NADH and NADPH are vital cellular redox cofactors but can form non-functional hydrates (named NAD(P)HX) spontaneously or enzymatically that compete with enzymes dependent on NAD(P)H, impairing normal enzyme function. Here we report on the functional characterization of components of a potential NAD(P)H repair pathway in plants comprising a stereospecific dehydratase (NNRD) and an epimerase (NNRE), the latter being fused to a vitamin B6 salvage enzyme. Through the use of the recombinant proteins, we show that the ATP-dependent NNRD and NNRE act concomitantly to restore NAD(P)HX to NAD(P)H. NNRD behaves as a tetramer and NNRE as a dimer, but the proteins do not physically interact. In vivo fluorescence analysis demonstrates that the proteins are localized to mitochondria and/or plastids, implicating these as the key organelles where this repair is required. Expression analysis indicates that whereas NNRE is present ubiquitously, NNRD is restricted to seeds but appears to be dispensable during the normal Arabidopsis life cycle.
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Affiliation(s)
- Maite Colinas
- From the Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Holly V Shaw
- From the Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Sylvain Loubéry
- From the Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Markus Kaufmann
- From the Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Michael Moulin
- From the Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Teresa B Fitzpatrick
- From the Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland
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Plecko B, Paul K, Mills P, Clayton P, Paschke E, Maier O, Hasselmann O, Schmiedel G, Kanz S, Connolly M, Wolf N, Struys E, Stockler S, Abela L, Hofer D. Pyridoxine responsiveness in novel mutations of the PNPO gene. Neurology 2014; 82:1425-33. [PMID: 24658933 DOI: 10.1212/wnl.0000000000000344] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether patients with pyridoxine-responsive seizures but normal biomarkers for antiquitin deficiency and normal sequencing of the ALDH7A1 gene may have PNPO mutations. METHODS We sequenced the PNPO gene in 31 patients who fulfilled the above-mentioned criteria. RESULTS We were able to identify 11 patients carrying 3 novel mutations of the PNPO gene. In 6 families, a homozygous missense mutation p.Arg225His in exon 7 was identified, while 1 family was compound heterozygous for a novel missense mutation p.Arg141Cys in exon 5 and a deletion c.279_290del in exon 3. Pathogenicity of the respective mutations was proven by absence in 100 control alleles and expression studies in CHO-K1 cell lines. The response to pyridoxine was prompt in 4, delayed in 2, on EEG only in 2, and initially absent in another 2 patients. Two unrelated patients homozygous for the p.Arg225His mutation experienced status epilepticus when switched to pyridoxal 5'-phosphate (PLP). CONCLUSIONS This study challenges the paradigm of exclusive PLP responsiveness in patients with pyridoxal 5'-phosphate oxidase deficiency and underlines the importance of consecutive testing of pyridoxine and PLP in neonates with antiepileptic drug-resistant seizures. Patients with pyridoxine response but normal biomarkers for antiquitin deficiency should undergo PNPO mutation analysis.
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Affiliation(s)
- Barbara Plecko
- From the Department of Pediatrics (B.P., L.A.), Division of Child Neurology, University Hospital Zurich, Switzerland; the Department of Pediatrics (B.P.), Division of Neurology and Inborn Errors of Metabolism, Medical University Graz, Austria; radiz-"Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases University of Zurich" (B.P., L.A.); CRC Clinical Research Center (B.P.), University Childrens' Hospital Zurich, Switzerland; the Laboratory of Metabolic Diseases (K.P., E.P., D.H.), Department of Pediatrics, University Hospital Graz, Austria; UCL Institute of Child Health (P.M., P.C.), Clinical and Molecular Genetics Unit, London, UK; Childrens Hospital St. Gallen (O.M., O.H.), Switzerland; the Department of Pediatrics (G.H.), Klinikum Esslingen; the Department of Pediatrics (S.K.), St. Marien Hospital, Landshut, Germany; the Division of Child Neurology (M.C.) and Division of Biochemical Diseases (S.S.), Department of Pediatrics, University of British Columbia, Vancouver, Canada; the Department of Pediatrics, Division of Child Neurology (N.W.), VU University Medical Center and Neuroscience Campus Amsterdam; and the Department of Clinical Chemistry (E.S.), Vrije Universiteit Amsterdam, the Netherlands
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Mills PB, Camuzeaux SSM, Footitt EJ, Mills KA, Gissen P, Fisher L, Das KB, Varadkar SM, Zuberi S, McWilliam R, Stödberg T, Plecko B, Baumgartner MR, Maier O, Calvert S, Riney K, Wolf NI, Livingston JH, Bala P, Morel CF, Feillet F, Raimondi F, Del Giudice E, Chong WK, Pitt M, Clayton PT. Epilepsy due to PNPO mutations: genotype, environment and treatment affect presentation and outcome. Brain 2014; 137:1350-60. [PMID: 24645144 PMCID: PMC3999720 DOI: 10.1093/brain/awu051] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The first described patients with pyridox(am)ine 5'-phosphate oxidase deficiency all had neonatal onset seizures that did not respond to treatment with pyridoxine but responded to treatment with pyridoxal 5'-phosphate. Our data suggest, however, that the clinical spectrum of pyridox(am)ine 5'-phosphate oxidase deficiency is much broader than has been reported in the literature. Sequencing of the PNPO gene was undertaken for a cohort of 82 individuals who had shown a reduction in frequency and severity of seizures in response to pyridoxine or pyridoxal 5'-phosphate. Novel sequence changes were studied using a new cell-free expression system and a mass spectrometry-based assay for pyridoxamine phosphate oxidase. Three groups of patients with PNPO mutations that had reduced enzyme activity were identified: (i) patients with neonatal onset seizures responding to pyridoxal 5'-phosphate (n = 6); (ii) a patient with infantile spasms (onset 5 months) responsive to pyridoxal 5'-phosphate (n = 1); and (iii) patients with seizures starting under 3 months of age responding to pyridoxine (n = 8). Data suggest that certain genotypes (R225H/C and D33V) are more likely to result in seizures that to respond to treatment with pyridoxine. Other mutations seem to be associated with infertility, miscarriage and prematurity. However, the situation is clearly complex with the same combination of mutations being seen in patients who responded and did not respond to pyridoxine. It is possible that pyridoxine responsiveness in PNPO deficiency is affected by prematurity and age at the time of the therapeutic trial. Other additional factors that are likely to influence treatment response and outcome include riboflavin status and how well the foetus has been supplied with vitamin B6 by the mother. For some patients there was a worsening of symptoms on changing from pyridoxine to pyridoxal 5'-phosphate. Many of the mutations in PNPO affected residues involved in binding flavin mononucleotide or pyridoxal 5'-phosphate and many of them showed residual enzyme activity. One sequence change (R116Q), predicted to affect flavin mononucleotide binding and binding of the two PNPO dimers, and with high residual activity was found in Groups (ii) and (iii). This sequence change has been reported in the 1000 Genomes project suggesting it could be a polymorphism but alternatively it could be a common mutation, perhaps responsible for the susceptibility locus for genetic generalized epilepsy on 17q21.32 (close to rs72823592). We believe the reduction in PNPO activity and B6-responsive epilepsy in the patients reported here indicates that it contributes to the pathogenesis of epilepsy.
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Affiliation(s)
- Philippa B Mills
- 1 Clinical and Molecular Genetics Unit, UCL Institute of Child Health, 30 Guilford St, London WC1N 1EH, UK
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Lienhart WD, Gudipati V, Macheroux P. The human flavoproteome. Arch Biochem Biophys 2013; 535:150-62. [PMID: 23500531 PMCID: PMC3684772 DOI: 10.1016/j.abb.2013.02.015] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/21/2013] [Accepted: 02/23/2013] [Indexed: 11/26/2022]
Abstract
Vitamin B2 (riboflavin) is an essential dietary compound used for the enzymatic biosynthesis of FMN and FAD. The human genome contains 90 genes encoding for flavin-dependent proteins, six for riboflavin uptake and transformation into the active coenzymes FMN and FAD as well as two for the reduction to the dihydroflavin form. Flavoproteins utilize either FMN (16%) or FAD (84%) while five human flavoenzymes have a requirement for both FMN and FAD. The majority of flavin-dependent enzymes catalyze oxidation-reduction processes in primary metabolic pathways such as the citric acid cycle, β-oxidation and degradation of amino acids. Ten flavoproteins occur as isozymes and assume special functions in the human organism. Two thirds of flavin-dependent proteins are associated with disorders caused by allelic variants affecting protein function. Flavin-dependent proteins also play an important role in the biosynthesis of other essential cofactors and hormones such as coenzyme A, coenzyme Q, heme, pyridoxal 5'-phosphate, steroids and thyroxine. Moreover, they are important for the regulation of folate metabolites by using tetrahydrofolate as cosubstrate in choline degradation, reduction of N-5.10-methylenetetrahydrofolate to N-5-methyltetrahydrofolate and maintenance of the catalytically competent form of methionine synthase. These flavoenzymes are discussed in detail to highlight their role in health and disease.
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Affiliation(s)
| | | | - Peter Macheroux
- Graz University of Technology, Institute of Biochemistry, Petersgasse 12, A-8010 Graz, Austria
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Ghatge MS, Contestabile R, di Salvo ML, Desai JV, Gandhi AK, Camara CM, Florio R, González IN, Parroni A, Schirch V, Safo MK. Pyridoxal 5'-phosphate is a slow tight binding inhibitor of E. coli pyridoxal kinase. PLoS One 2012; 7:e41680. [PMID: 22848564 PMCID: PMC3404986 DOI: 10.1371/journal.pone.0041680] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 06/24/2012] [Indexed: 11/18/2022] Open
Abstract
Pyridoxal 5′-phosphate (PLP) is a cofactor for dozens of B6 requiring enzymes. PLP reacts with apo-B6 enzymes by forming an aldimine linkage with the ε-amino group of an active site lysine residue, thus yielding the catalytically active holo-B6 enzyme. During protein turnover, the PLP is salvaged by first converting it to pyridoxal by a phosphatase and then back to PLP by pyridoxal kinase. Nonetheless, PLP poses a potential toxicity problem for the cell since its reactive 4′-aldehyde moiety forms covalent adducts with other compounds and non-B6 proteins containing thiol or amino groups. The regulation of PLP homeostasis in the cell is thus an important, yet unresolved issue. In this report, using site-directed mutagenesis, kinetic, spectroscopic and chromatographic studies we show that pyridoxal kinase from E. coli forms a complex with the product PLP to form an inactive enzyme complex. Evidence is presented that, in the inhibited complex, PLP has formed an aldimine bond with an active site lysine residue during catalytic turnover. The rate of dissociation of PLP from the complex is very slow, being only partially released after a 2-hour incubation with PLP phosphatase. Interestingly, the inactive pyridoxal kinase•PLP complex can be partially reactivated by transferring the tightly bound PLP to an apo-B6 enzyme. These results open new perspectives on the mechanism of regulation and role of pyridoxal kinase in the Escherichia coli cell.
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Affiliation(s)
- Mohini S. Ghatge
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Roberto Contestabile
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Roma, Italy
| | - Martino L. di Salvo
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Roma, Italy
| | - Jigar V. Desai
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Amit K. Gandhi
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Christina M. Camara
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Rita Florio
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Roma, Italy
| | - Isabel N. González
- Consiglio Nazionale delle Ricerche, Istituto di Biologia Agroambientale e Forestale, Monterotondo Scalo, Roma, Italy
- Institute of Biocomputation and Physics of Complex Systems, Universidad de Zaragoza, Zaragoza, Spain
| | - Alessia Parroni
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Roma, Italy
| | - Verne Schirch
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Martin K. Safo
- Department of Medicinal Chemistry, Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Hilario E, Li Y, Niks D, Fan L. The structure of a Xanthomonas general stress protein involved in citrus canker reveals its flavin-binding property. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:846-53. [PMID: 22751670 DOI: 10.1107/s0907444912014126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 03/31/2012] [Indexed: 11/11/2022]
Abstract
Xanthomonas citri pv. citri (Xac) causes citrus canker and affects citrus agriculture worldwide. Functional genetic analysis has indicated that a putative general stress protein (XacGSP) encoded by the Xac2369 gene is involved in the bacterial infection. In this report, the crystal structure of XacGSP was determined to 2.5 Å resolution. There are four XacGSP molecules in the crystal asymmetric unit. Each XacGSP monomer folds into a six-stranded antiparallel β-barrel flanked by five α-helices. A C-terminal extension protrudes from the sixth β-strand of the β-barrel and pairs with its counterpart from another monomer to form a bridge between the two subunits of an XacGSP dimer. Two XacGSP dimers cross over each other to form a tetramer; the β-barrels from one dimer contact the β-barrels of the other, while the two bridges are distant from each other and do not make contacts. The three-dimensional structure of the XacGSP monomer is very similar to those of pyridoxine 5-phosphate oxidases, a group of enzymes that use flavin mononucleotide (FMN) as a cofactor. Consistent with this, purified XacGSP protein binds to both FMN and flavin adenine dinucleotide (FAD), suggesting that XacGSP may help the bacteria to react against the oxidative stress induced by the defense mechanisms of the plant.
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Affiliation(s)
- Eduardo Hilario
- Department of Biochemistry, University of California-Riverside, Riverside, California, USA
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