1
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Pina AF, Sousa SF, Cerqueira NMFSA. The Catalytic Mechanism of Pdx2 Glutaminase Driven by a Cys-His-Glu Triad: A Computational Study. Chembiochem 2021; 23:e202100555. [PMID: 34762772 DOI: 10.1002/cbic.202100555] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/10/2021] [Indexed: 11/08/2022]
Abstract
The catalytic mechanism of Pdx2 was studied with atomic detail employing the computational ONIOM hybrid QM/MM methodology. Pdx2 employs a Cys-His-Glu catalytic triad to deaminate glutamine to glutamate and ammonia - the source of the nitrogen of pyridoxal 5'-phosphate (PLP). This enzyme is, therefore, a rate-limiting step in the PLP biosynthetic pathway of Malaria and Tuberculosis pathogens that rely on this mechanism to obtain PLP. For this reason, Pdx2 is considered a novel and promising drug target to treat these diseases. The results obtained show that the catalytic mechanism of Pdx2 occurs in six steps that can be divided into four stages: (i) activation of Cys87 , (ii) deamination of glutamine with the formation of the glutamyl-thioester intermediate, (iii) hydrolysis of the formed intermediate, and (iv) enzymatic turnover. The kinetic data available in the literature (19.1-19.5 kcal mol-1 ) agree very well with the calculated free energy barrier of the hydrolytic step (18.2 kcal.mol-11 ), which is the rate-limiting step of the catalytic process when substrate is readily available in the active site. This catalytic mechanism differs from other known amidases in three main points: i) it requires the activation of the nucleophile Cys87 to a thiolate; ii) the hydrolysis occurs in a single step and therefore does not require the formation of a second tetrahedral reaction intermediate, as it is proposed, and iii) Glu198 does not have a direct role in the catalytic process. Together, these results can be used for the synthesis of new transition state analogue inhibitors capable of inhibiting Pdx2 and impair diseases like Malaria and Tuberculosis.
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Affiliation(s)
- André F Pina
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal.,UCIBIO - Applied Molecular Biosciences Unit, BioSIM - Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal
| | - Sérgio F Sousa
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal.,UCIBIO - Applied Molecular Biosciences Unit, BioSIM - Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal
| | - Nuno M F S A Cerqueira
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal.,UCIBIO - Applied Molecular Biosciences Unit, BioSIM - Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal
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2
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Barra ALC, Ullah N, Morão LG, Wrenger C, Betzel C, Nascimento AS. Structural Dynamics and Perspectives of Vitamin B6 Biosynthesis Enzymes in Plasmodium: Advances and Open Questions. Front Cell Infect Microbiol 2021; 11:688380. [PMID: 34327152 PMCID: PMC8313854 DOI: 10.3389/fcimb.2021.688380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
Malaria is still today one of the most concerning diseases, with 219 million infections in 2019, most of them in Sub-Saharan Africa and Latin America, causing approx. 409,000 deaths per year. Despite the tremendous advances in malaria treatment and prevention, there is still no vaccine for this disease yet available and the increasing parasite resistance to already existing drugs is becoming an alarming issue globally. In this context, several potential targets for the development of new drug candidates have been proposed and, among those, the de novo biosynthesis pathway for the B6 vitamin was identified to be a promising candidate. The reason behind its significance is the absence of the pathway in humans and its essential presence in the metabolism of major pathogenic organisms. The pathway consists of two enzymes i.e. Pdx1 (PLP synthase domain) and Pdx2 (glutaminase domain), the last constituting a transient and dynamic complex with Pdx1 as the prime player and harboring the catalytic center. In this review, we discuss the structural biology of Pdx1 and Pdx2, together with and the understanding of the PLP biosynthesis provided by the crystallographic data. We also highlight the existing evidence of the effect of PLP synthesis inhibition on parasite proliferation. The existing data provide a flourishing environment for the structure-based design and optimization of new substrate analogs that could serve as inhibitors or even suicide inhibitors.
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Affiliation(s)
- Angélica Luana C Barra
- Pólo TerRa, São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil.,Institute of Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, University of Hamburg, Hamburg, Germany
| | - Najeeb Ullah
- Institute of Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, University of Hamburg, Hamburg, Germany
| | - Luana G Morão
- Pólo TerRa, São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Christian Betzel
- Institute of Biochemistry and Molecular Biology, Laboratory for Structural Biology of Infection and Inflammation, University of Hamburg, Hamburg, Germany
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3
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Han Y, He L, Qi Y, Zhao Y, Pan Y, Fang B, Li S, Zhang JZH, Zhang L. Identification of three new compounds that directly target human serine hydroxymethyltransferase 2. Chem Biol Drug Des 2020; 97:221-230. [PMID: 32779873 DOI: 10.1111/cbdd.13774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 06/15/2020] [Accepted: 07/12/2020] [Indexed: 11/28/2022]
Abstract
Mitochondrial serine hydroxymethyltransferase 2 (SHMT2) is an important drug target in the one-carbon metabolic pathway, since its activity is critical for purine and pyrimidine biosynthesis. Additionally, it plays a prominent role during metabolic reprogramming of cancer cells, and SHMT2 inhibitors have proven useful as anticancer drugs. Compared to drugs targeting one-carbon metabolic enzymes (mainly dihydrofolate reductase and thymidylate synthase) that have been used for clinical treatment of cancer, efficient SHMT2-specific inhibitors are lacking. Therefore, we established a direct system for virtual screening, protein expression, and identification of inhibitors targeting SHMT2. First, 27 compounds qualifying as potential SHMT2 inhibitors were selected for biological activity verification through virtual screening of the 210 thousand compounds registered in the Specs database. Second, these 27 hits were subjected to quick screening by an in vitro non-competitive kinetic assay of SHMT2 single-enzyme catalysis. This allowed us to identify three compounds featuring medium-strength and non-competitive inhibition of SHMT2: AM-807/42004511 (IC50 = 14.52 ± 4.1665 μM), AM-807/40675298 (IC50 = 12.74 ± 5.8991 μM), and AM-807/42004633 (IC50 = 9.43 ± 0.5646 μM). We describe a quick screening method for the identification of inhibitors targeting SHMT2, providing a basis for subsequent identification and screening of new inhibitors.
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Affiliation(s)
- Yanfang Han
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Liping He
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Yifei Qi
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China
| | - Yue Zhao
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Yue Pan
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Bohuan Fang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Sha Li
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - John Z H Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China.,Department of Chemistry, New York University, New York, NY, USA
| | - Lujia Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China
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4
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Barra ALC, Dantas LDOC, Morão LG, Gutierrez RF, Polikarpov I, Wrenger C, Nascimento AS. Essential Metabolic Routes as a Way to ESKAPE From Antibiotic Resistance. Front Public Health 2020; 8:26. [PMID: 32257985 PMCID: PMC7093009 DOI: 10.3389/fpubh.2020.00026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/27/2020] [Indexed: 02/03/2023] Open
Abstract
Antibiotic resistance is a worldwide concern that requires a concerted action from physicians, patients, governmental agencies, and academia to prevent infections and the spread of resistance, track resistant bacteria, improve the use of current antibiotics, and develop new antibiotics. Despite the efforts spent so far, the current antibiotics in the market are restricted to only five general targets/pathways highlighting the need for basic research focusing on the discovery and evaluation of new potential targets. Here we interrogate two biosynthetic pathways as potentially druggable pathways in bacteria. The biosynthesis pathway for thiamine (vitamin B1), absent in humans, but found in many bacteria, including organisms in the group of the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter sp.) and the biosynthesis pathway for pyridoxal 5'-phosphate and its vitamers (vitamin B6), found in S. aureus. Using current genomic data, we discuss the possibilities of inhibition of enzymes in the pathway and review the current state of the art in the scientific literature.
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Affiliation(s)
| | | | - Luana Galvão Morão
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Raíssa F. Gutierrez
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Carsten Wrenger
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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5
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Are S, Gatreddi S, Jakkula P, Qureshi IA. Structural attributes and substrate specificity of pyridoxal kinase from Leishmania donovani. Int J Biol Macromol 2020; 152:812-827. [PMID: 32105687 DOI: 10.1016/j.ijbiomac.2020.02.257] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/22/2020] [Accepted: 02/23/2020] [Indexed: 11/26/2022]
Abstract
The enzyme pyridoxal kinase (PdxK) catalyzes the conversion of pyridoxal to pyridoxal-5'-phosphate (PLP) using ATP as the co-factor. The product pyridoxal-5'-phosphate plays a key role in several biological processes such as transamination, decarboxylation and deamination. In the present study, full-length ORF of PdxK from Leishmania donovani (LdPdxK) was cloned and then purified using affinity chromatography. LdPdxK exists as a homo-dimer in solution and shows more activity at near to physiological pH. Biochemical analysis of LdPdxK with pyridoxal, pyridoxamine, pyridoxine and ginkgotoxin revealed its affinity preference towards different substrates. The secondary structure analysis using circular dichroism spectroscopy showed LdPdxK to be predominantly α-helical in organization which tends to decline at lower and higher pH. Simultaneously, LdPdxK was crystallized and its three-dimensional structure in complex with ADP and different substrates were determined. Crystal structure of LdPdxK delineated that it has a central core of β-sheets surrounded by α-helices with a conserved GTGD ribokinase motif. The structures of LdPdxK disclosed no major structural changes between ADP and ADP- substrate bound structures. In addition, comparative structural analysis highlighted the key differences between the active site pockets of leishmanial and human PdxK, rendering LdPdxK an attractive candidate for the designing of novel and specific inhibitors.
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Affiliation(s)
- Sayanna Are
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India
| | - Santhosh Gatreddi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India
| | - Pranay Jakkula
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India
| | - Insaf Ahmed Qureshi
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, Telangana, India.
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6
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Krishnan A, Kloehn J, Lunghi M, Soldati-Favre D. Vitamin and cofactor acquisition in apicomplexans: Synthesis versus salvage. J Biol Chem 2020; 295:701-714. [PMID: 31767680 PMCID: PMC6970920 DOI: 10.1074/jbc.aw119.008150] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Apicomplexa phylum comprises diverse parasitic organisms that have evolved from a free-living ancestor. These obligate intracellular parasites exhibit versatile metabolic capabilities reflecting their capacity to survive and grow in different hosts and varying niches. Determined by nutrient availability, they either use their biosynthesis machineries or largely depend on their host for metabolite acquisition. Because vitamins cannot be synthesized by the mammalian host, the enzymes required for their synthesis in apicomplexan parasites represent a large repertoire of potential therapeutic targets. Here, we review recent advances in metabolic reconstruction and functional studies coupled to metabolomics that unravel the interplay between biosynthesis and salvage of vitamins and cofactors in apicomplexans. A particular emphasis is placed on Toxoplasma gondii, during both its acute and latent stages of infection.
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Affiliation(s)
- Aarti Krishnan
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva CMU, 1 Rue Michel-Servet, 1211 Geneva 4 Switzerland
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva CMU, 1 Rue Michel-Servet, 1211 Geneva 4 Switzerland
| | - Matteo Lunghi
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva CMU, 1 Rue Michel-Servet, 1211 Geneva 4 Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva CMU, 1 Rue Michel-Servet, 1211 Geneva 4 Switzerland
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7
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Krishnan A, Kloehn J, Lunghi M, Soldati-Favre D. Vitamin and cofactor acquisition in apicomplexans: Synthesis versus salvage. J Biol Chem 2020. [DOI: 10.1016/s0021-9258(17)49928-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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8
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Lykins JD, Filippova EV, Halavaty AS, Minasov G, Zhou Y, Dubrovska I, Flores KJ, Shuvalova LA, Ruan J, El Bissati K, Dovgin S, Roberts CW, Woods S, Moulton JD, Moulton H, McPhillie MJ, Muench SP, Fishwick CWG, Sabini E, Shanmugam D, Roos DS, McLeod R, Anderson WF, Ngô HM. CSGID Solves Structures and Identifies Phenotypes for Five Enzymes in Toxoplasma gondii. Front Cell Infect Microbiol 2018; 8:352. [PMID: 30345257 PMCID: PMC6182094 DOI: 10.3389/fcimb.2018.00352] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/14/2018] [Indexed: 12/23/2022] Open
Abstract
Toxoplasma gondii, an Apicomplexan parasite, causes significant morbidity and mortality, including severe disease in immunocompromised hosts and devastating congenital disease, with no effective treatment for the bradyzoite stage. To address this, we used the Tropical Disease Research database, crystallography, molecular modeling, and antisense to identify and characterize a range of potential therapeutic targets for toxoplasmosis. Phosphoglycerate mutase II (PGMII), nucleoside diphosphate kinase (NDK), ribulose phosphate 3-epimerase (RPE), ribose-5-phosphate isomerase (RPI), and ornithine aminotransferase (OAT) were structurally characterized. Crystallography revealed insights into the overall structure, protein oligomeric states and molecular details of active sites important for ligand recognition. Literature and molecular modeling suggested potential inhibitors and druggability. The targets were further studied with vivoPMO to interrupt enzyme synthesis, identifying the targets as potentially important to parasitic replication and, therefore, of therapeutic interest. Targeted vivoPMO resulted in statistically significant perturbation of parasite replication without concomitant host cell toxicity, consistent with a previous CRISPR/Cas9 screen showing PGM, RPE, and RPI contribute to parasite fitness. PGM, RPE, and RPI have the greatest promise for affecting replication in tachyzoites. These targets are shared between other medically important parasites and may have wider therapeutic potential.
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Affiliation(s)
- Joseph D. Lykins
- Pritzker School of Medicine, University of Chicago, Chicago, IL, United States
| | - Ekaterina V. Filippova
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Andrei S. Halavaty
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - George Minasov
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Ying Zhou
- Department of Ophthalmology and Visual Sciences, University of Chicago, Chicago, IL, United States
| | - Ievgeniia Dubrovska
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Kristin J. Flores
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Ludmilla A. Shuvalova
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Jiapeng Ruan
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Kamal El Bissati
- Department of Ophthalmology and Visual Sciences, University of Chicago, Chicago, IL, United States
| | - Sarah Dovgin
- Illinois Math and Science Academy, Aurora, IL, United States
| | - Craig W. Roberts
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Stuart Woods
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | | | - Hong Moulton
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR, United States
| | - Martin J. McPhillie
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Stephen P. Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Colin W. G. Fishwick
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Elisabetta Sabini
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | | | - David S. Roos
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Rima McLeod
- Department of Ophthalmology and Visual Sciences, University of Chicago, Chicago, IL, United States
- Department of Pediatrics (Infectious Diseases), Institute of Genomics, Genetics, and Systems Biology, Global Health Center, Toxoplasmosis Center, CHeSS, The College, University of Chicago, Chicago, IL, United States
| | - Wayne F. Anderson
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Huân M. Ngô
- Center for Structural Genomics of Infectious Diseases and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- BrainMicro LLC, New Haven, CT, United States
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9
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Fernandes HS, Ramos MJ, Cerqueira NMFSA. Catalytic Mechanism of the Serine Hydroxymethyltransferase: A Computational ONIOM QM/MM Study. ACS Catal 2018. [DOI: 10.1021/acscatal.8b02321] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Henrique S. Fernandes
- UCIBIO@REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Maria João Ramos
- UCIBIO@REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Nuno M. F. S. A. Cerqueira
- UCIBIO@REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
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10
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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: 179] [Impact Index Per Article: 29.8] [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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11
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Intrapartum Nurse Perception of Labor Support After Implementation of the Coping With Labor Algorithm. J Perinat Educ 2018; 27:152-162. [PMID: 30364311 DOI: 10.1891/1058-1243.27.3.152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The purpose of this research project was to determine if using the Coping with Labor Algorithm would lead to changes in the perception of the intrapartum (IP) nurses' beliefs toward birth practices and frequency of labor support interventions. Twenty-three participants completed the preintervention survey, which included the IP Nurses' Belief Toward Birth Practice Scale and the Labor Support Scale. Following completion of the preintervention survey, participants received a copy of the Coping with Labor Algorithm and Toolkit and then began implementation of the Coping with Labor Algorithm. After implementation, 13 IP nurses completed the postintervention survey. The surveyed IP nurses reported positive changes in their perceived frequency of labor support and a slight change in their birth beliefs.
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12
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Amornwatcharapong W, Maenpuen S, Chitnumsub P, Leartsakulpanich U, Chaiyen P. Human and Plasmodium serine hydroxymethyltransferases differ in rate-limiting steps and pH-dependent substrate inhibition behavior. Arch Biochem Biophys 2017; 630:91-100. [PMID: 28760597 DOI: 10.1016/j.abb.2017.07.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 01/14/2023]
Abstract
Serine hydroxymethyltransferase (SHMT), an essential enzyme for cell growth and development, catalyzes the transfer of -CH2OH from l-serine to tetrahydrofolate (THF) to form glycine and 5,10-methylenetetrahydrofolate (MTHF) which is used for nucleotide synthesis. Insights into the ligand binding and inhibition properties of human cytosolic SHMT (hcSHMT) and Plasmodium SHMT (PvSHMT) are crucial for designing specific drugs against malaria and cancer. The results presented here revealed strong and pH-dependent THF inhibition of hcSHMT. In contrast, in PvSHMT, THF inhibition and the influence of pH were not as pronounced. Ligand binding experiments performed at various pH values indicated that the hcSHMT:Gly complex binds THF more tightly at lower pH conditions, while the binding affinity of the PvSHMT:Gly complex for THF is not pH-dependent. Pre-steady state kinetic (rapid-quench) analysis of hcSHMT showed burst kinetics, indicating that glycine formation occurs fastest in the first turnover relative to the subsequent turnovers i.e. glycine release is the rate-limiting step in the hcSHMT reaction. All data suggest that excess THF likely binds E:Gly binary complex and forms the E:Gly:THF dead-end complex before glycine is released. A unique flap motif found in the structure of hcSHMT may be the key structural feature that imparts these described characteristics of hcSHMT.
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Affiliation(s)
- Watcharee Amornwatcharapong
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Somchart Maenpuen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi 20131, Thailand
| | - Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120, Thailand
| | - Ubolsree Leartsakulpanich
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120, Thailand.
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Department of Biomolecular Science and Engineering, School of Biomolecular Science & Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand.
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13
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Unique substrate specificity of ornithine aminotransferase from Toxoplasma gondii. Biochem J 2017; 474:939-955. [DOI: 10.1042/bcj20161021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/25/2017] [Accepted: 01/25/2017] [Indexed: 12/28/2022]
Abstract
Toxoplasma gondii is a protozoan parasite of medical and veterinary relevance responsible for toxoplasmosis in humans. As an efficacious vaccine remains a challenge, chemotherapy is still the most effective way to combat the disease. In search of novel druggable targets, we performed a thorough characterization of the putative pyridoxal 5′-phosphate (PLP)-dependent enzyme ornithine aminotransferase from T. gondii ME49 (TgOAT). We overexpressed the protein in Escherichia coli and analysed its molecular and kinetic properties by UV-visible absorbance, fluorescence and CD spectroscopy, in addition to kinetic studies of both the steady state and pre-steady state. TgOAT is largely similar to OATs from other species regarding its general transamination mechanism and spectral properties of PLP; however, it does not show a specific ornithine aminotransferase activity like its human homologue, but exhibits both N-acetylornithine and γ-aminobutyric acid (GABA) transaminase activity in vitro, suggesting a role in both arginine and GABA metabolism in vivo. The presence of Val79 in the active site of TgOAT in place of Tyr, as in its human counterpart, provides the necessary room to accommodate N-acetylornithine and GABA, resembling the active site arrangement of GABA transaminases. Moreover, mutation of Val79 to Tyr results in a change of substrate preference between GABA, N-acetylornithine and L-ornithine, suggesting a key role of Val79 in defining substrate specificity. The findings that TgOAT possesses parasite-specific structural features as well as differing substrate specificity from its human homologue make it an attractive target for anti-toxoplasmosis inhibitor design that can be exploited for chemotherapeutic intervention.
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Kersting D, Krüger M, Sattler JM, Mueller AK, Kaiser A. A suggested vital function for eIF-5A and dhs genes during murine malaria blood-stage infection. FEBS Open Bio 2016; 6:860-72. [PMID: 27516964 PMCID: PMC4971841 DOI: 10.1002/2211-5463.12093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/07/2016] [Accepted: 05/29/2016] [Indexed: 12/30/2022] Open
Abstract
The biological function of the post-translational modification hypusine in the eukaryotic initiation factor 5A (EIF-5A) in eukaryotes is still not understood. Hypusine is formed by two sequential enzymatic steps at a specific lysine residue in the precursor protein EIF-5A. One important biological function of EIF-5A which was recently identified is the translation of polyproline-rich mRNA, suggesting its biological relevance in a variety of biological processes. Hypusinated eIF-5A controls the proliferation of cancer cells and inflammatory processes in malaria. It was shown that pharmacological inhibition of the enzymes involved in this pathway, deoxyhypusine synthase (DHS) and the deoxyhypusine hydroxylase (DOHH), arrested the growth of malaria parasites. Down-regulation of both the malarial eIF-5A and dhs genes by in vitro and in vivo silencing led to decreased transcript levels and protein expression and, in turn, to low parasitemia, confirming a critical role of hypusination in eIF-5A for proliferation in Plasmodium. To further investigate whether eIF-5A and the activating enzyme DHS are essential for Plasmodium erythrocytic stages, targeted gene disruption was performed in the rodent malaria parasite Plasmodium berghei. Full disruption of both genes was not successful; instead parasites harboring the episome for eIF-5A and dhs genes were obtained, suggesting that these genes may perform vital functions during the pathogenic blood cell stage. Next, a knock-in strategy was pursued for both endogenous genes eIF-5A and dhs from P. berghei. The latter resulted in viable recombinant parasites, strengthening the observation that they might be essential for proliferation during asexual development of the malaria parasite.
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Affiliation(s)
- David Kersting
- Institute for Pharmacogenetics Medical Research Centre University Duisburg-Essen Germany
| | - Mirko Krüger
- Institute for Pharmacogenetics Medical Research Centre University Duisburg-Essen Germany
| | - Julia M Sattler
- Parasitology Unit Centre for Infectious Diseases University Hospital Heidelberg Germany; Centre for Infectious Diseases, Integrative Parasitology University Hospital Heidelberg Germany
| | - Ann-Kristin Mueller
- Parasitology Unit Centre for Infectious Diseases University Hospital Heidelberg Germany; German Center for Infectious Diseases Heidelberg Germany
| | - Annette Kaiser
- Institute for Pharmacogenetics Medical Research Centre University Duisburg-Essen Germany
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Fang X, Reifman J, Wallqvist A. Modeling metabolism and stage-specific growth of Plasmodium falciparum HB3 during the intraerythrocytic developmental cycle. MOLECULAR BIOSYSTEMS 2015; 10:2526-37. [PMID: 25001103 DOI: 10.1039/c4mb00115j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The human malaria parasite Plasmodium falciparum goes through a complex life cycle, including a roughly 48-hour-long intraerythrocytic developmental cycle (IDC) in human red blood cells. A better understanding of the metabolic processes required during the asexual blood-stage reproduction will enhance our basic knowledge of P. falciparum and help identify critical metabolic reactions and pathways associated with blood-stage malaria. We developed a metabolic network model that mechanistically links time-dependent gene expression, metabolism, and stage-specific growth, allowing us to predict the metabolic fluxes, the biomass production rates, and the timing of production of the different biomass components during the IDC. We predicted time- and stage-specific production of precursors and macromolecules for P. falciparum (strain HB3), allowing us to link specific metabolites to specific physiological functions. For example, we hypothesized that coenzyme A might be involved in late-IDC DNA replication and cell division. Moreover, the predicted ATP metabolism indicated that energy was mainly produced from glycolysis and utilized for non-metabolic processes. Finally, we used the model to classify the entire tricarboxylic acid cycle into segments, each with a distinct function, such as superoxide detoxification, glutamate/glutamine processing, and metabolism of fumarate as a byproduct of purine biosynthesis. By capturing the normal metabolic and growth progression in P. falciparum during the IDC, our model provides a starting point for further elucidation of strain-specific metabolic activity, host-parasite interactions, stress-induced metabolic responses, and metabolic responses to antimalarial drugs and drug candidates.
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Affiliation(s)
- Xin Fang
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Ft. Detrick, MD 21702, USA.
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Joslin AC, Green R, German JB, Lange MC. Concept mapping One-Carbon Metabolism to model future ontologies for nutrient-gene-phenotype interactions. GENES AND NUTRITION 2014; 9:419. [PMID: 25091042 DOI: 10.1007/s12263-014-0419-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 07/10/2014] [Indexed: 01/16/2023]
Abstract
Advances in the development of bioinformatic tools continue to improve investigators' ability to interrogate, organize, and derive knowledge from large amounts of heterogeneous information. These tools often require advanced technical skills not possessed by life scientists. User-friendly, low-barrier-to-entry methods of visualizing nutrigenomics information are yet to be developed. We utilized concept mapping software from the Institute for Human and Machine Cognition to create a conceptual model of diet and health-related data that provides a foundation for future nutrigenomics ontologies describing published nutrient-gene/polymorphism-phenotype data. In this model, maps containing phenotype, nutrient, gene product, and genetic polymorphism interactions are visualized as triples of two concepts linked together by a linking phrase. These triples, or "knowledge propositions," contextualize aggregated data and information into easy-to-read knowledge maps. Maps of these triples enable visualization of genes spanning the One-Carbon Metabolism (OCM) pathway, their sequence variants, and multiple literature-mined associations including concepts relevant to nutrition, phenotypes, and health. The concept map development process documents the incongruity of information derived from pathway databases versus literature resources. This conceptual model highlights the importance of incorporating information about genes in upstream pathways that provide substrates, as well as downstream pathways that utilize products of the pathway under investigation, in this case OCM. Other genes and their polymorphisms, such as TCN2 and FUT2, although not directly involved in OCM, potentially alter OCM pathway functionality. These upstream gene products regulate substrates such as B12. Constellations of polymorphisms affecting the functionality of genes along OCM, together with substrate and cofactor availability, may impact resultant phenotypes. These conceptual maps provide a foundational framework for development of nutrient-gene/polymorphism-phenotype ontologies and systems visualization.
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Affiliation(s)
- A C Joslin
- Department of Food Science and Technology, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
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