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Sasidharan S, Saudagar P. An anti-leishmanial compound 4',7-dihydroxyflavone elicits ROS-mediated apoptosis-like death in Leishmania parasite. FEBS J 2023. [PMID: 36871140 DOI: 10.1111/febs.16770] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/12/2023] [Accepted: 03/02/2023] [Indexed: 03/06/2023]
Abstract
The treatment for leishmaniasis is currently plagued by side effects such as toxicity and the emergence of drug resistance to the available repertoire of drugs, as well as the expense of these drugs. Considering such rising concerns, we report the anti-leishmanial activity and mechanism of a flavone compound 4',7-dihydroxyflavone (TI 4). Four flavanoids were initially screened for anti-leishmanial activity and cytotoxicity. The results showed that the compound TI 4 exhibited higher activity and selectivity index at the same time as maintaining low cytotoxicity. Preliminary microscopic studies and fluorescence-activated cell sorting analysis reported that the parasite underwent apoptosis on TI 4 treatment. Further in-depth studies revealed high reactive oxygen species (ROS) production and thiol levels in the parasites, suggesting ROS-mediated apoptosis in the parasites upon TI 4 treatment. Other apoptotic indicators such as intracellular Ca2+ and mitochondrial membrane potential also indicated the onset of apoptosis in the treated parasites. The mRNA expression levels signified that the redox metabolism genes were upregulated by two-fold along with the apoptotic genes. In summary, the use of TI 4 on Leishmania parasites induces ROS-mediated apoptosis; therefore, the compound has immense potential to be an anti-leishmanial drug. However, in vivo studies would be required to ascertain its safety and efficacy before we can exploit the compound against the growing leishmaniasis crisis.
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Affiliation(s)
- Santanu Sasidharan
- Department of Biotechnology, National Institute of Technology, Warangal, India
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology, Warangal, India
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2
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Marchesani F, Zangelmi E, Murtas G, Costanzi E, Ullah R, Peracchi A, Bruno S, Pollegioni L, Mozzarelli A, Storici P, Campanini B. L-Serine Biosynthesis in The Human Central Nervous System: Structure and Function of Phosphoserine Aminotransferase. Protein Sci 2023; 32:e4609. [PMID: 36851825 PMCID: PMC10031235 DOI: 10.1002/pro.4609] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/12/2023] [Accepted: 02/23/2023] [Indexed: 03/01/2023]
Abstract
Organisms from all kingdoms of life synthesize L-serine from 3-phosphoglycerate through the phosphorylated pathway, a three-step diversion of glycolysis. Phosphoserine aminotransferase (PSAT) catalyzes the intermediate step, the pyridoxal 5'-phosphate-dependent transamination of 3-phosphohydroxypyruvate and L-glutamate to O-phosphoserine and α-ketoglutarate. PSAT is particularly relevant in the central nervous system of mammals because L-serine is the metabolic precursor of D-serine, cysteine, phospholipids, and nucleotides. Several mutations in the human psat gene have been linked to serine deficiency disorders, characterized by severe neurological symptoms. Furthermore, PSAT is overexpressed in many tumors and this overexpression has been associated with poor clinical outcomes. Here, we report the detailed functional and structural characterization of the recombinant human PSAT. The reaction catalyzed by PSAT is reversible, with an equilibrium constant of about 10, and the enzyme is very efficient, with a kcat /Km of 5.9 × 106 M-1 s-1 , thus contributing in driving the pathway towards the products despite the extremely unfavorable first step catalyzed by 3-phosphoglycerate dehydrogenase. The three-dimensional X-ray crystal structure of PSAT was solved in the substrate-free as well as in the O-phosphoserine-bound forms. Both structures contain eight protein molecules in the asymmetric unit, arranged in four dimers, with a bound cofactor in each subunit. In the substrate-free form, the active site of PSAT contains a sulfate ion that, in the substrate-bound form, is replaced by the phosphate group of O-phosphoserine. Interestingly, fast crystal soaking used to produce the substrate-bound form allowed the trapping of different intermediates along the catalytic cycle. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Erika Zangelmi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Giulia Murtas
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Elisa Costanzi
- Protein Facility, Elettra Sincrotrone Trieste S.C.p.A., Trieste, Italy
| | - Raheem Ullah
- Protein Facility, Elettra Sincrotrone Trieste S.C.p.A., Trieste, Italy
- Present address: Structural Biology Lab, NIBGE, Faisalabad, Pakistan
| | - Alessio Peracchi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Stefano Bruno
- Department of Food and Drug, University of Parma, Parma, Italy
| | - Loredano Pollegioni
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | | | - Paola Storici
- Protein Facility, Elettra Sincrotrone Trieste S.C.p.A., Trieste, Italy
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3
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Sasidharan S, Saudagar P. Knockout of Tyrosine Aminotransferase Gene by Homologous Recombination Arrests Growth and Disrupts Redox Homeostasis in Leishmania Parasite. Parasitol Res 2022; 121:3229-3241. [PMID: 36056961 DOI: 10.1007/s00436-022-07642-0] [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: 05/17/2022] [Accepted: 08/24/2022] [Indexed: 11/26/2022]
Abstract
Tyrosine aminotransferase is a well-characterized enzyme in the Leishmania parasite, but the role of TAT in the parasite functioning remains largely unknown. In this study, we attempt to gain a better understanding of the enzyme's role in the parasite by gene knockout and overexpression of the TAT gene. The overexpression of TAT protein was well tolerated by the parasites in two independent repeats. Single knockout of TAT gene by homologous recombination, LdTAT+/- displayed distinct retardation in the proliferation rates and entered the death phase immediately. Morphology of LdTAT+/- parasites had important structural defects as they rounded up with elongated flagella. Gene regulation studies suggested the upregulation of key apoptotic and redox metabolism genes in LdTAT+/-. Moreover, LdTAT+/- cells accumulated higher ROS, thiols, intracellular Ca2+ concentrations, and mitochondrial membrane depolarization signifying the onset of apoptosis. Tocopherol levels were reduced by 50% in LdTAT+/- suggesting the involvement of TAT in tocopherol biosynthesis in the parasite. Overall, our results provide the first evidence that gene knockout of TAT results in apoptosis and that TAT is required for the survival and viability of Leishmania donovani.
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Affiliation(s)
- Santanu Sasidharan
- Department of Biotechnology, National Institute of Technology, Warangal, Telangana, 506004, India
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology, Warangal, Telangana, 506004, India.
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4
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Human cytosolic transaminases: side activities and patterns of discrimination towards physiologically available alternative substrates. Cell Mol Life Sci 2022; 79:421. [PMID: 35834009 PMCID: PMC9283133 DOI: 10.1007/s00018-022-04439-3] [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: 04/14/2022] [Revised: 06/01/2022] [Accepted: 06/20/2022] [Indexed: 11/03/2022]
Abstract
Transaminases play key roles in central metabolism, transferring the amino group from a donor substrate to an acceptor. These enzymes can often act, with low efficiency, on compounds different from the preferred substrates. To understand what might have shaped the substrate specificity of this class of enzymes, we examined the reactivity of six human cytosolic transaminases towards amino acids whose main degradative pathways do not include any transamination. We also tested whether sugars and sugar phosphates could serve as alternative amino group acceptors for these cytosolic enzymes. Each of the six aminotransferases reacted appreciably with at least three of the alternative amino acid substrates in vitro, albeit at usually feeble rates. Reactions with L-Thr, L-Arg, L-Lys and L-Asn were consistently very slow-a bias explained in part by the structural differences between these amino acids and the preferred substrates of the transaminases. On the other hand, L-His and L-Trp reacted more efficiently, particularly with GTK (glutamine transaminase K; also known as KYAT1). This points towards a role of GTK in the salvage of L-Trp (in cooperation with ω-amidase and possibly with the cytosolic malate dehydrogenase, MDH1, which efficiently reduced the product of L-Trp transamination). Finally, the transaminases were extremely ineffective at utilizing sugars and sugar derivatives, with the exception of the glycolytic intermediate dihydroxyacetone phosphate, which was slowly but appreciably transaminated by some of the enzymes to yield serinol phosphate. Evidence for the formation of this compound in a human cell line was also obtained. We discuss the biological and evolutionary implications of our results.
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5
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Koper K, Han SW, Pastor DC, Yoshikuni Y, Maeda HA. Evolutionary Origin and Functional Diversification of Aminotransferases. J Biol Chem 2022; 298:102122. [PMID: 35697072 PMCID: PMC9309667 DOI: 10.1016/j.jbc.2022.102122] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 11/30/2022] Open
Abstract
Aminotransferases (ATs) are pyridoxal 5′-phosphate–dependent enzymes that catalyze the transamination reactions between amino acid donor and keto acid acceptor substrates. Modern AT enzymes constitute ∼2% of all classified enzymatic activities, play central roles in nitrogen metabolism, and generate multitude of primary and secondary metabolites. ATs likely diverged into four distinct AT classes before the appearance of the last universal common ancestor and further expanded to a large and diverse enzyme family. Although the AT family underwent an extensive functional specialization, many AT enzymes retained considerable substrate promiscuity and multifunctionality because of their inherent mechanistic, structural, and functional constraints. This review summarizes the evolutionary history, diverse metabolic roles, reaction mechanisms, and structure–function relationships of the AT family enzymes, with a special emphasis on their substrate promiscuity and multifunctionality. Comprehensive characterization of AT substrate specificity is still needed to reveal their true metabolic functions in interconnecting various branches of the nitrogen metabolic network in different organisms.
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Affiliation(s)
- Kaan Koper
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Sang-Woo Han
- The US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Yasuo Yoshikuni
- The US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Global Center for Food, Land, and Water Resources, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
| | - Hiroshi A Maeda
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
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Cannon Homaei S, Barone H, Kleppe R, Betari N, Reif A, Haavik J. ADHD symptoms in neurometabolic diseases: Underlying mechanisms and clinical implications. Neurosci Biobehav Rev 2021; 132:838-856. [PMID: 34774900 DOI: 10.1016/j.neubiorev.2021.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/09/2021] [Accepted: 11/09/2021] [Indexed: 12/16/2022]
Abstract
Neurometabolic diseases (NMDs) are typically caused by genetic abnormalities affecting enzyme functions, which in turn interfere with normal development and activity of the nervous system. Although the individual disorders are rare, NMDs are collectively relatively common and often lead to lifelong difficulties and high societal costs. Neuropsychiatric manifestations, including ADHD symptoms, are prominent in many NMDs, also when the primary biochemical defect originates in cells and tissues outside the nervous system. ADHD symptoms have been described in phenylketonuria, tyrosinemias, alkaptonuria, succinic semialdehyde dehydrogenase deficiency, X-linked ichthyosis, maple syrup urine disease, and several mitochondrial disorders, but are probably present in many other NMDs and may pose diagnostic and therapeutic challenges. Here we review current literature linking NMDs with ADHD symptoms. We cite emerging evidence that many NMDs converge on common neurochemical mechanisms that interfere with monoamine neurotransmitter synthesis, transport, metabolism, or receptor functions, mechanisms that are also considered central in ADHD pathophysiology and treatment. Finally, we discuss the therapeutic implications of these findings and propose a path forward to increase our understanding of these relationships.
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Affiliation(s)
- Selina Cannon Homaei
- Division of Psychiatry, Haukeland University Hospital, Norway; Department of Biomedicine, University of Bergen, Norway.
| | - Helene Barone
- Regional Resource Center for Autism, ADHD, Tourette Syndrome and Narcolepsy, Western Norway, Division of Psychiatry, Haukeland University Hospital, Norway.
| | - Rune Kleppe
- Division of Psychiatry, Haukeland University Hospital, Norway; Norwegian Centre for Maritime and Diving Medicine, Department of Occupational Medicine, Haukeland University Hospital, Norway.
| | - Nibal Betari
- Department of Biomedicine, University of Bergen, Norway.
| | - Andreas Reif
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Frankfurt am Main, Germany.
| | - Jan Haavik
- Division of Psychiatry, Haukeland University Hospital, Norway; Department of Biomedicine, University of Bergen, Norway.
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7
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Sasidharan S, Saudagar P. Flavones reversibly inhibit Leishmania donovani tyrosine aminotransferase by binding to the catalytic pocket: An integrated in silico-in vitro approach. Int J Biol Macromol 2020; 164:2987-3004. [PMID: 32798546 DOI: 10.1016/j.ijbiomac.2020.08.107] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/27/2020] [Accepted: 08/12/2020] [Indexed: 02/06/2023]
Abstract
The current drugs for treating Leishmaniasis are toxic, non-economical and with the emergence of drug resistance makes the need for novel therapeutics urgent and necessary. In the current study, we report the identification of compounds TI 1-5 against tyrosine aminotransferase of L. donovani from a curated ZINC15 database containing 183,659 compounds. These flavonoid compounds had binding energies < -8 kcal/mol and interacted with the active site residues S151, K286, C290, and P291. Assessment of physicochemical descriptors and ADMET properties established the drug likeliness of these compounds. The all-atom molecular dynamic simulations of the TAT-TI complexes exhibited stable geometrical properties and further trajectory analysis revealed the high-affinity interactions of TI 1, 3, 4, and 5 with the active site residues. DFT calculations reported the high electrophilic nature of TI 2 while other TI compounds demonstrated good kinetic stability and reactivity. From in vitro studies, TI 3 and TI 4 had the highest inhibition with Ki values of 0.9 ± 0.2 μM and 0.30 ± 0.1 μM, respectively. Taken together, the results from this study indicate the potentiality of TI 1, 3, 4, and 5 as anti-leishmanial leads, and these compounds can be exploited to manage the growing Leishmaniasis crisis in the world.
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Affiliation(s)
- Santanu Sasidharan
- Department of Biotechnology, National Institute of Technology, Warangal, 506004, Telangana, India
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology, Warangal, 506004, Telangana, India.
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8
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Sasidharan S, Saudagar P. Biochemical and structural characterization of tyrosine aminotransferase suggests broad substrate specificity and a two-state folding mechanism in Leishmania donovani. FEBS Open Bio 2019; 9:1769-1783. [PMID: 31393078 PMCID: PMC6768288 DOI: 10.1002/2211-5463.12715] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/20/2019] [Accepted: 08/07/2019] [Indexed: 11/09/2022] Open
Abstract
Tyrosine aminotransferase (TAT) is an aminotransferase with broad substrate specificity that catalyzes the transamination of aromatic amino acids in Leishmania donovani and plays a crucial role in the survival and pathogenicity of the parasite. In this study, we have biochemically characterized tyrosine aminotransferase from Leishmania donovani using in vitro and in silico techniques. Leishmania donovani tyrosine aminotransferase (LdTAT) was cloned into the pET28a(+) vector and expressed in the BL21 strain of Escherichia coli. The Ni-NTA-purified protein was then characterized biochemically, and its various kinetic parameters were investigated. The apparent Km value for the tyrosine-pyruvate pair was determined to be 3.5 ± 0.9 mm, and Vmax was analyzed to be at 11.7 ± 1.5 μm·min.μg-1 . LdTAT was found to exhibit maximum activity at 50 °C and at a pH of 8.0. Cofactor identification for LdTAT showed that pyridoxal-5-phosphate (PLP) binds with a Km value of 23.59 ± 3.99 μm and that the phosphate group is vital for the activity of the enzyme. Sequence analysis revealed that S151, Y256, K286, and P291 are conserved residues and form hydrogen bonds with PLP. Urea-based denaturation studies revealed a biphasic folding mechanism involving N→X→D states. Molecular dynamic simulations of modeled LdTAT at various conditions were performed to understand enzyme behavior and interactions at the molecular level. The biochemical and structural divergence between host and parasite TAT suggests the LdTAT has evolved to utilize pyruvate rather than α-ketoglutarate as co-substrate. Furthermore, our data suggest that LdTAT may be a potential drug target due to its divergence in structure and substrate specificity from the host.
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Affiliation(s)
- Santanu Sasidharan
- Department of BiotechnologyNational Institute of TechnologyWarangalIndia
| | - Prakash Saudagar
- Department of BiotechnologyNational Institute of TechnologyWarangalIndia
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9
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Ipson BR, Green RA, Wilson JT, Watson JN, Faull KF, Fisher AL. Tyrosine aminotransferase is involved in the oxidative stress response by metabolizing meta-tyrosine in Caenorhabditis elegans. J Biol Chem 2019; 294:9536-9554. [PMID: 31043480 PMCID: PMC6579467 DOI: 10.1074/jbc.ra118.004426] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 04/24/2019] [Indexed: 12/11/2022] Open
Abstract
Under oxidative stress conditions, hydroxyl radicals can oxidize the phenyl ring of phenylalanine, producing the abnormal tyrosine isomer meta-tyrosine (m-tyrosine). m-Tyrosine levels are commonly used as a biomarker of oxidative stress, and its accumulation has recently been reported to adversely affect cells, suggesting a direct role for m-tyrosine in oxidative stress effects. We found that the Caenorhabditis elegans ortholog of tyrosine aminotransferase (TATN-1)-the first enzyme involved in the metabolic degradation of tyrosine-is up-regulated in response to oxidative stress and directly activated by the oxidative stress-responsive transcription factor SKN-1. Worms deficient in tyrosine aminotransferase activity displayed increased sensitivity to multiple sources of oxidative stress. Biochemical assays revealed that m-tyrosine is a substrate for TATN-1-mediated deamination, suggesting that TATN-1 also metabolizes m-tyrosine. Consistent with a toxic effect of m-tyrosine and a protective function of TATN-1, tatn-1 mutant worms exhibited delayed development, marked reduction in fertility, and shortened lifespan when exposed to m-tyrosine. A forward genetic screen identified a mutation in the previously uncharacterized gene F01D4.5-homologous with human transcription factor 20 (TCF20) and retinoic acid-induced 1 (RAI1)-that suppresses the adverse phenotypes observed in m-tyrosine-treated tatn-1 mutant worms. RNA-Seq analysis of F01D4.5 mutant worms disclosed a significant reduction in the expression of specific isoforms of genes encoding ribosomal proteins, suggesting that alterations in protein synthesis or ribosome structure could diminish the adverse effects of m-tyrosine. Our findings uncover a critical role for tyrosine aminotransferase in the oxidative stress response via m-tyrosine metabolism.
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Affiliation(s)
- Brett R Ipson
- From the Department of Cell Systems and Anatomy
- the Center for Healthy Aging, and
| | - Rebecca A Green
- the Ludwig Institute for Cancer Research, San Diego, La Jolla, California 92093
| | | | | | - Kym F Faull
- the Pasarow Mass Spectrometry Laboratory, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, and
| | - Alfred L Fisher
- the Center for Healthy Aging, and
- the Division of Geriatrics, Gerontology, and Palliative Medicine, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
- Geriatric Research, Education and Clinical Center (GRECC), South Texas Veterans Affairs Healthcare System, San Antonio, Texas 78229
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10
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Maggi M, Scotti C. Enzymes in Metabolic Anticancer Therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1148:173-199. [PMID: 31482500 DOI: 10.1007/978-981-13-7709-9_9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cancer treatment has greatly improved over the last 50 years, but it remains challenging in several cases. Useful therapeutic targets are normally unique peculiarities of cancer cells that distinguish them from normal cells and that can be tackled with appropriate drugs. It is now known that cell metabolism is rewired during tumorigenesis and metastasis as a consequence of oncogene activation and oncosuppressors inactivation, leading to a new cellular homeostasis typically directed towards anabolism. Because of these modifications, cells can become strongly or absolutely dependent on specific substrates, like sugars, lipids or amino acids. Cancer addictions are a relevant target for therapy, as removal of an essential substrate can lead to their selective cell-cycle arrest or even to cell death, leaving normal cells untouched. Enzymes can act as powerful agents in this respect, as demonstrated by asparaginase, which has been included in the treatment of Acute Lymphoblastic Leukemia for half a century. In this review, a short outline of cancer addictions will be provided, focusing on the main cancer amino acid dependencies described so far. Therapeutic enzymes which have been already experimented at the clinical level will be discussed, along with novel potential candidates that we propose as new promising molecules. The intrinsic limitations of their present molecular forms, along with molecular engineering solutions to explore, will also be presented.
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Affiliation(s)
- Maristella Maggi
- Department of Molecular Medicine, Unit of Immunology and General Pathology, University of Pavia, Pavia, Italy.
| | - Claudia Scotti
- Department of Molecular Medicine, Unit of Immunology and General Pathology, University of Pavia, Pavia, Italy
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11
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Nývltová E, Šut'ák R, Žárský V, Harant K, Hrdý I, Tachezy J. Lateral gene transfer of p-cresol- and indole-producing enzymes from environmental bacteria to Mastigamoeba balamuthi. Environ Microbiol 2017; 19:1091-1102. [PMID: 27902886 DOI: 10.1111/1462-2920.13636] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/10/2016] [Accepted: 11/22/2016] [Indexed: 12/01/2022]
Abstract
p-Cresol and indole are volatile biologically active products of the bacterial degradation of tyrosine and tryptophan respectively. They are typically produced by bacteria in animal intestines, soil and various sediments. Here, we demonstrate that the free-living eukaryote Mastigamoeba balamuthi and its pathogenic relative Entamoeba histolytica produce significant amounts of indole via tryptophanase activity. Unexpectedly, M. balamuthi also produces p-cresol in concentrations that are bacteriostatic to non-p-cresol-producing bacteria. The ability of M. balamuthi to produce p-cresol, which has not previously been observed in any eukaryotic microbe, was gained due to the lateral acquisition of a bacterial gene for 4-hydroxyphenylacetate decarboxylase (HPAD). In bacteria, the genes for HPAD and the S-adenosylmethionine-dependent activating enzyme (AE) are present in a common operon. In M. balamuthi, HPAD displays a unique fusion with the AE that suggests the operon-mediated transfer of genes from a bacterial donor. We also clarified that the tyrosine-to-4-hydroxyphenylacetate conversion proceeds via the Ehrlich pathway. The acquisition of the bacterial HPAD gene may provide M. balamuthi a competitive advantage over other microflora in its native habitat.
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Affiliation(s)
- Eva Nývltová
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Robert Šut'ák
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Vojtěch Žárský
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Karel Harant
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Charles University in Prague, Faculty of Science, Prague, Czech Republic
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12
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Moreno MA, Alonso A, Alcolea PJ, Abramov A, de Lacoba MG, Abendroth J, Zhang S, Edwards T, Lorimer D, Myler PJ, Larraga V. Tyrosine aminotransferase from Leishmania infantum: A new drug target candidate. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2014; 4:347-54. [PMID: 25516846 PMCID: PMC4266777 DOI: 10.1016/j.ijpddr.2014.06.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The tyrosine aminotransferase from Leishmania infantum has a cytoplasmic distribution and is able to use the oxoacid ketomethiobutyrate, as a co-substrate. L. infantum tyrosine aminotransferase is over-expressed in infective and nitric oxide resistant parasites. The structural differences with the mammalian TAT, together with cellular distribution, expression pattern and activity, support that LiTAT is a drug target candidate. The structure-based model of the pharmacophore of LiTAT with specific substrate ketomethiobutyrate has been generated.
Leishmania infantum is the etiological agent of zoonotic visceral leishmaniasis in the Mediterranean basin. The disease is fatal without treatment, which has been based on antimonial pentavalents for more than 60 years. Due to resistances, relapses and toxicity to current treatment, the development of new drugs is required. The structure of the L. infantum tyrosine aminotransferase (LiTAT) has been recently solved showing important differences with the mammalian orthologue. The characterization of LiTAT is reported herein. This enzyme is cytoplasmic and is over-expressed in the more infective stages and nitric oxide resistant parasites. Unlike the mammalian TAT, LiTAT is able to use ketomethiobutyrate as co-substrate. The pharmacophore model of LiTAT with this specific co-substrate is described herein. This may allow the identification of new inhibitors present in the databases. All the data obtained support that LiTAT is a good target candidate for the development of new anti-leishmanial drugs.
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Affiliation(s)
- Miguel Angel Moreno
- Departamento de Microbiología Molecular y Servicio de Bioinformática y Bioestadística, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), calle Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Ana Alonso
- Departamento de Microbiología Molecular y Servicio de Bioinformática y Bioestadística, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), calle Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Pedro Jose Alcolea
- Departamento de Microbiología Molecular y Servicio de Bioinformática y Bioestadística, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), calle Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Ariel Abramov
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA ; Seattle Biomedical Research Institute, 307 Westlake Avenue North, Seattle, WA 98109, USA
| | - Mario García de Lacoba
- Departamento de Microbiología Molecular y Servicio de Bioinformática y Bioestadística, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), calle Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Jan Abendroth
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA ; Emerald Bio Inc., 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
| | - Sunny Zhang
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA ; Seattle Biomedical Research Institute, 307 Westlake Avenue North, Seattle, WA 98109, USA
| | - Thomas Edwards
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA ; Emerald Bio Inc., 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
| | - Don Lorimer
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA ; Emerald Bio Inc., 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
| | - Peter John Myler
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA ; Seattle Biomedical Research Institute, 307 Westlake Avenue North, Seattle, WA 98109, USA ; Department of Global Health, University of Washington, Seattle, WA 98125, USA ; Department of Biomedical Informatics & Medical Education, University of Washington, Seattle, WA 98125, USA
| | - Vicente Larraga
- Departamento de Microbiología Molecular y Servicio de Bioinformática y Bioestadística, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), calle Ramiro de Maeztu, 9, 28040 Madrid, Spain
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13
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Shen B, Fang T, Yang T, Jones G, Irwin DM, Zhang S. Relaxed evolution in the tyrosine aminotransferase gene tat in old world fruit bats (Chiroptera: Pteropodidae). PLoS One 2014; 9:e97483. [PMID: 24824435 PMCID: PMC4019583 DOI: 10.1371/journal.pone.0097483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 04/16/2014] [Indexed: 12/01/2022] Open
Abstract
Frugivorous and nectarivorous bats fuel their metabolism mostly by using carbohydrates and allocate the restricted amounts of ingested proteins mainly for anabolic protein syntheses rather than for catabolic energy production. Thus, it is possible that genes involved in protein (amino acid) catabolism may have undergone relaxed evolution in these fruit- and nectar-eating bats. The tyrosine aminotransferase (TAT, encoded by the Tat gene) is the rate-limiting enzyme in the tyrosine catabolic pathway. To test whether the Tat gene has undergone relaxed evolution in the fruit- and nectar-eating bats, we obtained the Tat coding region from 20 bat species including four Old World fruit bats (Pteropodidae) and two New World fruit bats (Phyllostomidae). Phylogenetic reconstructions revealed a gene tree in which all echolocating bats (including the New World fruit bats) formed a monophyletic group. The phylogenetic conflict appears to stem from accelerated TAT protein sequence evolution in the Old World fruit bats. Our molecular evolutionary analyses confirmed a change in the selection pressure acting on Tat, which was likely caused by a relaxation of the evolutionary constraints on the Tat gene in the Old World fruit bats. Hepatic TAT activity assays showed that TAT activities in species of the Old World fruit bats are significantly lower than those of insectivorous bats and omnivorous mice, which was not caused by a change in TAT protein levels in the liver. Our study provides unambiguous evidence that the Tat gene has undergone relaxed evolution in the Old World fruit bats in response to changes in their metabolism due to the evolution of their special diet.
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Affiliation(s)
- Bin Shen
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
| | - Tao Fang
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
| | - Tianxiao Yang
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
| | - Gareth Jones
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - David M. Irwin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Shuyi Zhang
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
- * E-mail:
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14
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Muratore KE, Engelhardt BE, Srouji JR, Jordan MI, Brenner SE, Kirsch JF. Molecular function prediction for a family exhibiting evolutionary tendencies toward substrate specificity swapping: recurrence of tyrosine aminotransferase activity in the Iα subfamily. Proteins 2013; 81:1593-609. [PMID: 23671031 PMCID: PMC3823064 DOI: 10.1002/prot.24318] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 04/11/2013] [Accepted: 04/19/2013] [Indexed: 11/17/2022]
Abstract
The subfamily Iα aminotransferases are typically categorized as having narrow specificity toward carboxylic amino acids (AATases), or broad specificity that includes aromatic amino acid substrates (TATases). Because of their general role in central metabolism and, more specifically, their association with liver-related diseases in humans, this subfamily is biologically interesting. The substrate specificities for only a few members of this subfamily have been reported, and the reliable prediction of substrate specificity from protein sequence has remained elusive. In this study, a diverse set of aminotransferases was chosen for characterization based on a scoring system that measures the sequence divergence of the active site. The enzymes that were experimentally characterized include both narrow-specificity AATases and broad-specificity TATases, as well as AATases with broader-specificity and TATases with narrower-specificity than the previously known family members. Molecular function and phylogenetic analyses underscored the complexity of this family's evolution as the TATase function does not follow a single evolutionary thread, but rather appears independently multiple times during the evolution of the subfamily. The additional functional characterizations described in this article, alongside a detailed sequence and phylogenetic analysis, provide some novel clues to understanding the evolutionary mechanisms at work in this family.
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Affiliation(s)
- Kathryn E Muratore
- Department of Molecular and Cell Biology, University of California, Berkeley, California
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15
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Watanabe N, James MNG. Structural insights for the substrate recognition mechanism of LL-diaminopimelate aminotransferase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:1528-33. [PMID: 21435399 DOI: 10.1016/j.bbapap.2011.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 03/02/2011] [Accepted: 03/09/2011] [Indexed: 11/25/2022]
Abstract
The enzymes involved in the lysine biosynthetic pathway have long been considered to be attractive targets for novel antibiotics due to the absence of this pathway in humans. Recently, a novel pyridoxal 5'-phosphate (PLP) dependent enzyme called LL-diaminopimelate aminotransferase (LL-DAP-AT) was identified in the lysine biosynthetic pathway of plants and Chlamydiae. Understanding its function and substrate recognition mechanism would be an important initial step toward designing novel antibiotics targeting LL-DAP-AT. The crystal structures of LL-DAP-AT from Arabidopsis thaliana in complex with various substrates and analogues have been solved recently. These structures revealed how L-glutamate and LL-DAP are recognized by LL-DAP-AT without significant conformational changes in the enzyme's backbone structure. This review article summarizes the recent developments in the structural characterization and the inhibitor design of LL-DAP-AT from A. thaliana. This article is part of a Special Issue entitled: Pyridoxal Phospate Enzymology.
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Affiliation(s)
- Nobuhiko Watanabe
- Department of Biochemistry, School of Medicine and Systems Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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16
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Tyrosine aminotransferase: biochemical and structural properties and molecular dynamics simulations. Protein Cell 2010; 1:1023-32. [PMID: 21153519 DOI: 10.1007/s13238-010-0128-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 10/19/2010] [Indexed: 10/18/2022] Open
Abstract
Tyrosine aminotransferase (TAT) catalyzes the transamination of tyrosine and other aromatic amino acids. The enzyme is thought to play a role in tyrosinemia type II, hepatitis and hepatic carcinoma recovery. The objective of this study is to investigate its biochemical and structural characteristics and substrate specificity in order to provide insight regarding its involvement in these diseases. Mouse TAT (mTAT) was cloned from a mouse cDNA library, and its recombinant protein was produced using Escherichia coli cells and purified using various chromatographic techniques. The recombinant mTAT is able to catalyze the transamination of tyrosine using α-ketoglutaric acid as an amino group acceptor at neutral pH. The enzyme also can use glutamate and phenylalanine as amino group donors and p-hydroxy-phenylpyruvate, phenylpyruvate and alpha-ketocaproic acid as amino group acceptors. Through macromolecular crystallography we have determined the mTAT crystal structure at 2.9 Å resolution. The crystal structure revealed the interaction between the pyridoxal-5'-phosphate cofactor and the enzyme, as well as the formation of a disulphide bond. The detection of disulphide bond provides some rational explanation regarding previously observed TAT inactivation under oxidative conditions and reactivation of the inactive TAT in the presence of a reducing agent. Molecular dynamics simulations using the crystal structures of Trypanosoma cruzi TAT and human TAT provided further insight regarding the substrate-enzyme interactions and substrate specificity. The biochemical and structural properties of TAT and the binding of its cofactor and the substrate may help in elucidation of the mechanism of TAT inhibition and activation.
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17
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Recombinant production of eight human cytosolic aminotransferases and assessment of their potential involvement in glyoxylate metabolism. Biochem J 2009; 422:265-72. [PMID: 19545238 DOI: 10.1042/bj20090748] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PH1 (primary hyperoxaluria type 1) is a severe inborn disorder of glyoxylate metabolism caused by a functional deficiency of the peroxisomal enzyme AGXT (alanine-glyoxylate aminotransferase), which converts glyoxylate into glycine using L-alanine as the amino-group donor. Even though pre-genomic studies indicate that other human transaminases can convert glyoxylate into glycine, in PH1 patients these enzymes are apparently unable to compensate for the lack of AGXT, perhaps due to their limited levels of expression, their localization in an inappropriate cell compartment or the scarcity of the required amino-group donor. In the present paper, we describe the cloning of eight human cytosolic aminotransferases, their recombinant expression as His6-tagged proteins and a comparative study on their ability to transaminate glyoxylate, using any standard amino acid as an amino-group donor. To selectively quantify the glycine formed, we have developed and validated an assay based on bacterial GO (glycine oxidase); this assay allows the detection of enzymes that produce glycine by transamination in the presence of mixtures of potential amino-group donors and without separation of the product from the substrates. We show that among the eight enzymes tested, only GPT (alanine transaminase) and PSAT1 (phosphoserine aminotransferase 1) can transaminate glyoxylate with good efficiency, using L-glutamate (and, for GPT, also L-alanine) as the best amino-group donor. These findings confirm that glyoxylate transamination can occur in the cytosol, in direct competition with the conversion of glyoxylate into oxalate. The potential implications for the treatment of primary hyperoxaluria are discussed.
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