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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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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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3
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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] [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 Biotechnology, National Institute of Technology, Warangal, India
| | - Prakash Saudagar
- Department of Biotechnology, National Institute of Technology, Warangal, India
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The Uptake and Metabolism of Amino Acids, and Their Unique Role in the Biology of Pathogenic Trypanosomatids. Pathogens 2018; 7:pathogens7020036. [PMID: 29614775 PMCID: PMC6027508 DOI: 10.3390/pathogens7020036] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 01/24/2023] Open
Abstract
Trypanosoma brucei, as well as Trypanosoma cruzi and more than 20 species of the genus Leishmania, form a group of flagellated protists that threaten human health. These organisms are transmitted by insects that, together with mammals, are their natural hosts. This implies that during their life cycles each of them faces environments with different physical, chemical, biochemical, and biological characteristics. In this work we review how amino acids are obtained from such environments, how they are metabolized, and how they and some of their intermediate metabolites are used as a survival toolbox to cope with the different conditions in which these parasites should establish the infections in the insects and mammalian hosts.
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Zhuo Y, Cordeiro CD, Hekmatyar SK, Docampo R, Prestegard JH. Dynamic nuclear polarization facilitates monitoring of pyruvate metabolism in Trypanosoma brucei. J Biol Chem 2017; 292:18161-18168. [PMID: 28887303 DOI: 10.1074/jbc.m117.807495] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Indexed: 11/06/2022] Open
Abstract
Dynamic nuclear polarization provides sensitivity improvements that make NMR a viable method for following metabolic conversions in real time. There are now many in vivo applications to animal systems and even to diagnosis of human disease. However, application to microbial systems is rare. Here we demonstrate its application to the pathogenic protozoan, Trypanosoma brucei, using hyperpolarized 13C1 pyruvate as a substrate and compare the parasite metabolism with that of commonly cultured mammalian cell lines, HEK-293 and Hep-G2. Metabolic differences between insect and bloodstream forms of T. brucei were also investigated. Significant differences are noted with respect to lactate, alanine, and CO2 production. Conversion of pyruvate to CO2 in the T. brucei bloodstream form provides new support for the presence of an active pyruvate dehydrogenase in this stage.
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Affiliation(s)
- You Zhuo
- From the Complex Carbohydrate Research Center
| | - Ciro D Cordeiro
- the Center for Tropical and Emerging Global Diseases, and.,the Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | | | - Roberto Docampo
- the Center for Tropical and Emerging Global Diseases, and.,the Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
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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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Moreno MA, Abramov A, Abendroth J, Alonso A, Zhang S, Alcolea PJ, Edwards T, Lorimer D, Myler PJ, Larraga V. Structure of tyrosine aminotransferase from Leishmania infantum. Acta Crystallogr F Struct Biol Commun 2014; 70:583-7. [PMID: 24817714 PMCID: PMC4014323 DOI: 10.1107/s2053230x14007845] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 04/08/2014] [Indexed: 11/12/2022] Open
Abstract
The trypanosomatid parasite Leishmania infantum is the causative agent of visceral leishmaniasis (VL), which is usually fatal unless treated. VL has an incidence of 0.5 million cases every year and is an important opportunistic co-infection in HIV/AIDS. Tyrosine aminotransferase (TAT) has an important role in the metabolism of trypanosomatids, catalyzing the first step in the degradation pathway of aromatic amino acids, which are ultimately converted into their corresponding L-2-oxoacids. Unlike the enzyme in Trypanosoma cruzi and mammals, L. infantum TAT (LiTAT) is not able to transaminate ketoglutarate. Here, the structure of LiTAT at 2.35 Å resolution is reported, and it is confirmed that the presence of two Leishmania-specific residues (Gln55 and Asn58) explains, at least in part, this specific reactivity. The difference in substrate specificity between leishmanial and mammalian TAT and the importance of this enzyme in parasite metabolism suggest that it may be a useful target in the development of new drugs against leishmaniasis.
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Affiliation(s)
- M. A. Moreno
- Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Calle Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - A. Abramov
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA
- Seattle Biomedical Research Institute, 307 Westlake Avenue North, Seattle, WA 98109, USA
| | - J. Abendroth
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA
- Emerald Bio Inc., 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
| | - A. Alonso
- Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Calle Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - S. Zhang
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA
- Seattle Biomedical Research Institute, 307 Westlake Avenue North, Seattle, WA 98109, USA
| | - P. J. Alcolea
- Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Calle Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - T. Edwards
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA
- Emerald Bio Inc., 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
| | - D. Lorimer
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), USA
- Emerald Bio Inc., 7869 NE Day Road West, Bainbridge Island, WA 98110, USA
| | - P. J. 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 and Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, WA 98125, USA
| | - V. Larraga
- Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CSIC), Calle Ramiro de Maeztu 9, 28040 Madrid, Spain
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Blankenfeldt W, Nowicki C, Montemartini-Kalisz M, Kalisz HM, Hecht HJ. Crystal structure of Trypanosoma cruzi tyrosine aminotransferase: substrate specificity is influenced by cofactor binding mode. Protein Sci 1999; 8:2406-17. [PMID: 10595543 PMCID: PMC2144194 DOI: 10.1110/ps.8.11.2406] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The crystal structure of tyrosine aminotransferase (TAT) from the parasitic protozoan Trypanosoma cruzi, which belongs to the aminotransferase subfamily Igamma, has been determined at 2.5 A resolution with the R-value R = 15.1%. T. cruzi TAT shares less than 15% sequence identity with aminotransferases of subfamily Ialpha but shows only two larger topological differences to the aspartate aminotransferases (AspATs). First, TAT contains a loop protruding from the enzyme surface in the larger cofactor-binding domain, where the AspATs have a kinked alpha-helix. Second, in the smaller substrate-binding domain, TAT has a four-stranded antiparallel beta-sheet instead of the two-stranded beta-sheet in the AspATs. The position of the aromatic ring of the pyridoxal-5'-phosphate cofactor is very similar to the AspATs but the phosphate group, in contrast, is closer to the substrate-binding site with one of its oxygen atoms pointing toward the substrate. Differences in substrate specificities of T. cruzi TAT and subfamily Ialpha aminotransferases can be attributed by modeling of substrate complexes mainly to this different position of the cofactor-phosphate group. Absence of the arginine, which in the AspATs fixes the substrate side-chain carboxylate group by a salt bridge, contributes to the inability of T. cruzi TAT to transaminate acidic amino acids. The preference of TAT for tyrosine is probably related to the ability of Asn17 in TAT to form a hydrogen bond to the tyrosine side-chain hydroxyl group.
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Affiliation(s)
- W Blankenfeldt
- Gesellschaft für Biotechnologische Forschung, Braunschweig, Germany
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Berger BJ, Dai WW, Wang H, Stark RE, Cerami A. Aromatic amino acid transamination and methionine recycling in trypanosomatids. Proc Natl Acad Sci U S A 1996; 93:4126-30. [PMID: 8633027 PMCID: PMC39498 DOI: 10.1073/pnas.93.9.4126] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Although trypanosomatids are known to rapidly transaminate exogenous aromatic amino acids in vitro and in vivo, the physiological significance of this reaction is not understood. In postmitochondrial supernatants prepared from Trypanosoma brucei brucei and Crithidia fasciculata, we have found that aromatic amino acids were the preferred amino donors for the transamination of alpha-ketomethiobutyrate to methionine. Intact C. fasciculata grown in the presence of [15N]tyrosine were found to contain detectable [15N]methionine, demonstrating that this reaction occurs in situ in viable cells. This process is the final step in the recycling of methionine from methylthioadenosine, a product of decarboxylated S-adenosylmethionine from the polyamine synthetic pathway. Mammalian liver, in contrast, preferentially used glutamine for this reaction and utilized a narrower range of amino donors than seen with the trypanosomatids. Studies with methylthioadenosine showed that this compound was readily converted to methionine, demonstrating a fully functional methionine-recycling pathway in trypanosomatids.
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Affiliation(s)
- B J Berger
- Picower Institute for Medical Research, Manhasset, NY 11030, USA
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