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Kumari P, Agrawal P, Umarao P, Ramachandran V, Gourinath S. Identification of Small Molecule Inhibitors Targeting Phosphoserine Phosphatase: A Novel Target for the Development of Antiamoebic Drugs. ACS OMEGA 2024; 9:27906-27918. [PMID: 38973836 PMCID: PMC11223228 DOI: 10.1021/acsomega.3c09439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/25/2024] [Accepted: 01/31/2024] [Indexed: 07/09/2024]
Abstract
Amoebiasis, a widespread disease caused by the protozoan parasite Entamoeba histolytica, poses challenges due to the adverse effects of existing antiamoebic drugs and rising drug resistance. Novel targeted drugs are in need of the hour to combat the prevalence of this disease. Given the significance of cysteine for Entamoeba survival, the rate-determining step in the serine (the sole substrate of cysteine synthesis) biosynthetic pathway, i.e., the conversion of 3-phosphoserine to l-serine catalyzed by phosphoserine phosphatase (PSP), emerges as a promising drug target. Our previous study unveils the essential role of EhPSP in amoebas' survival, particularly under oxidative stress, by increasing cysteine production. The study also revealed that EhPSP differs significantly from its human counterpart, both structurally and biochemically, highlighting its potential as a viable target for developing new antiamoebic drugs. In the present study, employing in silico screening of vast natural and synthetic small chemical compound libraries, we identified 21 potential EhPSP inhibitor molecules. Out of the 21 compounds examined, only five could inhibit the catalytic activity of EhPSP. The inhibition capability of these five compounds was subsequently validated by in silico binding free energy calculations, SPR-based real-time binding studies, and molecular simulations to assess the stability of the EhPSP-inhibitor complexes. By identifying the five potential inhibitors that can target cysteine synthesis via EhPSP, our findings establish EhPSP as a drug candidate that can serve as a foundation for antiamoebic drug research.
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Affiliation(s)
- Poonam Kumari
- International
Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
- Structural
Biology Lab, School of Life Sciences, Jawaharlal
Nehru University, New Delhi 110067, India
| | - Prakhar Agrawal
- International
Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Preeti Umarao
- Structural
Biology Lab, School of Life Sciences, Jawaharlal
Nehru University, New Delhi 110067, India
| | - Vijayan Ramachandran
- The
Centre for Innovation in Brain Sciences, University of Arizona, Tucson 85721, Arizona, United States
| | - Samudrala Gourinath
- Structural
Biology Lab, School of Life Sciences, Jawaharlal
Nehru University, New Delhi 110067, India
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Toh SI, Lo CL, Chang CY. Crystal structure of CmnB involved in the biosynthesis of the nonproteinogenic amino acid L-2,3-diaminopropionic acid. Acta Crystallogr F Struct Biol Commun 2023; 79:193-199. [PMID: 37405487 PMCID: PMC10327575 DOI: 10.1107/s2053230x23005769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/30/2023] [Indexed: 07/06/2023] Open
Abstract
L-2,3-Diaminopropionic acid (L-Dap) is a nonproteinogenic amino acid that plays as an important role as a building block in the biosynthesis of several natural products, including capreomycin, viomycin, zwittermicin, staphyloferrin and dapdiamide. A previous study reported that CmnB and CmnK are two enzymes that are involved in the formation of L-Dap in the biosynthesis of capreomycin. CmnB catalyzes the condensation reaction of O-phospho-L-serine and L-glutamic acid to generate N-(1-amino-1-carboxyl-2-ethyl)glutamic acid, which subsequently undergoes oxidative hydrolysis via CmnK to generate the product L-Dap. Here, the crystal structure of CmnB in complex with the reaction intermediate PLP-α-aminoacrylate is reported at 2.2 Å resolution. Notably, CmnB is the second known example of a PLP-dependent enzyme that forms a monomeric structure in crystal packing. The crystal structure of CmnB also provides insights into the catalytic mechanism of the enzyme and supports the biosynthetic pathway of L-Dap reported in previous studies.
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Affiliation(s)
- Shu-Ing Toh
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Chieh-Ling Lo
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| | - Chin-Yuan Chang
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Department of Biomedical Science and Environment Biology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
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3
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Pyne N, Paul S. Screening of medicinal plants unraveled the leishmanicidal credibility of Garcinia cowa; highlighting Norcowanin, a novel anti-leishmanial phytochemical through in-silico study. J Parasit Dis 2022; 46:202-214. [PMID: 35299910 PMCID: PMC8901847 DOI: 10.1007/s12639-021-01441-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/07/2021] [Indexed: 02/04/2023] Open
Abstract
Leishmaniasis, one of the most prevalent yet neglected parasitic causes of death, yearns for therapeutic control and treatment. Severely toxic and inefficient modern-day pentavalent antimonials, caters the search for naturally derived drugs, as efficient alternatives for disease treatment. The anti-promastigote activity of ten different plants selected for their ethnomedicinal properties revealed significant leishmanicidal capacity; the most potent being Garcinia cowa methanolic extract with an IC50 value of 21.4 µg/ml. Garcinia cowa, a plant endemic to North-Eastern India that is of the Clusiaceae family, is replete with such medicinal qualities as antimicrobial, antiviral, antiparasitic, and antiproliferative activities. Computational biology with its tools such as molecular docking has opened new horizons aimed at a better understanding of biological systems, complexes, and their interactions, and subsequently drug discovery via in silico techniques. Therefore, an in-silico study was designed to evaluate the binding capability of six phytochemicals- cowanin, cowanol, cowaxanthone, norcowanin, rubraxanthone, and a basic xanthone, found in Garcinia cowa against Pentamidine, a synthetic anti-leishmanial drug. The active sites of three characteristic enzymes belonging to the Leishmania donovani parasite: O-acetylserine sulfhydrylase (OASS), Trypanothione reductase (TryR), and N-Myristoyltransferase (NMT) were chosen as target proteins. Results revealed lower binding energies and higher affinities, of nearly all the phytochemicals with respect to Pentamidine, indicating their leishmanicidal potential. Norcowanin showed the lowest average binding of - 9.8 kcal/mol against all the three enzymes under study.
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Affiliation(s)
- Nibedita Pyne
- Laboratory of Cell and Molecular Biology, Department of Botany, Centre of Advanced Study, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019 India
| | - Santanu Paul
- Laboratory of Cell and Molecular Biology, Department of Botany, Centre of Advanced Study, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019 India
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4
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Lv H, Hu L, Xu J, Bo T, Wang W. Identification and functional analysis of the mitochondrial cysteine synthase TtCsa2 from Tetrahymena thermophila. J Cell Biochem 2021; 122:1817-1831. [PMID: 34427342 DOI: 10.1002/jcb.30136] [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: 02/06/2021] [Revised: 08/03/2021] [Accepted: 08/12/2021] [Indexed: 01/12/2023]
Abstract
Cysteine is a crucial component for all organisms and plays a critical role in the structure, stability, and catalytic functions of many proteins. Tetrahymena has reverse transsulfuration and de novo pathways for cysteine biosynthesis. Cysteine synthase is involved in the de novo cysteine biosynthesis and catalyzes the production of cysteine from O-acetylserine. The novel cysteine synthase TtCSA2 was identified from Tetrahymena thermophila. The TtCSA2 showed high expression levels at the log-phase and the sexual development stage. The TtCsa2 was localized on the outer mitochondrial membrane throughout different developmental stages. However, the truncated N-terminal signal peptide mutant TtCsa2-ΔN23 was localized into the mitochondria. His-TtCsa2 was expressed in Escherichia coli and purified using affinity chromatography. The His-TtCsa2 showed O-acetylserine sulfhydrylase and serine sulfhydrylase activities. Cysteine and glutathione contents decreased in the csa2KD mutant. Furthermore, mutant cells were sensitive to cadmium and copper stresses. This study indicated that the TtCSA2 was involved in the cysteine synthesis in mitochondria and related to heavy metal stresses resistance in Tetrahymena.
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Affiliation(s)
- Hongrui Lv
- School of Life Science, Shanxi University, Taiyuan, China.,Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Lina Hu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Jing Xu
- School of Life Science, Shanxi University, Taiyuan, China.,Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Tao Bo
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
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5
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A Competitive O-Acetylserine Sulfhydrylase Inhibitor Modulates the Formation of Cysteine Synthase Complex. Catalysts 2021. [DOI: 10.3390/catal11060700] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cysteine is the main precursor of sulfur-containing biological molecules in bacteria and contributes to the control of the cell redox state. Hence, this amino acid plays an essential role in microbial survival and pathogenicity and the reductive sulfate assimilation pathway is considered a promising target for the development of new antibacterials. Serine acetyltransferase (SAT) and O-acetylserine sulfhydrylase (OASS-A), the enzymes catalyzing the last two steps of cysteine biosynthesis, engage in the formation of the cysteine synthase (CS) complex. The interaction between SAT and OASS-A finely tunes cysteine homeostasis, and the development of inhibitors targeting either protein–protein interaction or the single enzymes represents an attractive strategy to undermine bacterial viability. Given the peculiar mode of interaction between SAT and OASS-A, which exploits the insertion of SAT C-terminal sequence into OASS-A active site, we tested whether a recently developed competitive inhibitor of OASS-A exhibited any effect on the CS stability. Through surface plasmon resonance spectroscopy, we (i) determined the equilibrium constant for the Salmonella Typhimurium CS complex formation and (ii) demonstrated that the inhibitor targeting OASS-A active site affects CS complex formation. For comparison, the Escherichia coli CS complex was also investigated, with the aim of testing the potential broad-spectrum activity of the candidate antimicrobial compound.
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6
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Brucella ovis Cysteine Biosynthesis Contributes to Peroxide Stress Survival and Fitness in the Intracellular Niche. Infect Immun 2021; 89:IAI.00808-20. [PMID: 33753413 DOI: 10.1128/iai.00808-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/15/2021] [Indexed: 11/20/2022] Open
Abstract
Brucella ovis is an ovine intracellular pathogen with tropism for the male genital tract. To establish and maintain infection, B. ovis must survive stressful conditions inside host cells, including low pH, nutrient limitation, and reactive oxygen species. The same conditions are often encountered in axenic cultures during stationary phase. Studies of stationary phase may thus inform our understanding of Brucella infection biology, yet the genes and pathways that are important in Brucella stationary-phase physiology remain poorly defined. We measured fitness of a barcoded pool of B. ovis Tn-himar mutants as a function of growth phase and identified cysE as a determinant of fitness in stationary phase. CysE catalyzes the first step in cysteine biosynthesis from serine, and we provide genetic evidence that two related enzymes, CysK1 and CysK2, function redundantly to catalyze cysteine synthesis at steps downstream of CysE. Deleting cysE (ΔcysE) or both cysK1 and cysK2 (ΔcysK1 ΔcysK2) results in premature entry into stationary phase, reduced culture yield, and sensitivity to exogenous hydrogen peroxide. These phenotypes can be chemically complemented by cysteine or glutathione. ΔcysE and ΔcysK1 ΔcysK2 strains have no defect in host cell entry in vitro but have significantly diminished intracellular fitness between 2 and 24 h postinfection. Our study has uncovered unexpected redundancy at the CysK step of cysteine biosynthesis in B. ovis and demonstrates that cysteine anabolism is a determinant of peroxide stress survival and fitness in the intracellular niche.
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7
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Lv H, Xu J, Bo T, Wang W. Characterization of Cystathionine β-Synthase TtCbs1 and Cysteine Synthase TtCsa1 Involved in Cysteine Biosynthesis in Tetrahymena thermophila. J Eukaryot Microbiol 2020; 68:e12834. [PMID: 33190347 DOI: 10.1111/jeu.12834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/21/2020] [Accepted: 11/07/2020] [Indexed: 12/19/2022]
Abstract
Cysteine is implicated in important biological processes. It is synthesized through two different pathways. Cystathionine β-synthase and cystathionine γ-lyase participate in the reverse transsulfuration pathway, while serine acetyltransferase and cysteine synthase function in the de novo pathway. Two evolutionarily related pyridoxal 5'-phosphate-dependent enzymes, cystathionine β-synthase TtCBS1 (TTHERM_00558300) and cysteine synthase TtCSA1 (TTHERM_00239430), were identified from a freshwater protozoan Tetrahymena thermophila. TtCbs1 contained the N-terminal heme binding domain, catalytic domain, and C-terminal regulatory domain, whereas TtCsa1 consisted of two α/β domains. The catalytic core of the two enzymes is similar. TtCBS1 and TtCSA1 showed high expression levels in the vegetative growth stage and decreased during the sexual developmental stage. TtCbs1 and TtCsa1 were localized in the cytoplasm throughout different developmental stages. His-TtCbs1 and His-TtCsa1 were expressed and purified in vitro. TtCbs1 catalyzed the canonical reaction with the highest velocity and possessed serine sulfhydrylase activity. TtCsa1 showed cysteine synthase activity with high Km for O-acetylserine and low Km for sulfide and also had serine sulfhydrylase activity toward serine. Both TtCbs1 and TtCsa1 catalyzed hydrogen sulfide producing. TtCBS1 knockdown and TtCSA1 knockout mutants affected cysteine and glutathione synthesis. TtCbs1 and TtCsa1 are involved in cysteine synthesis through two different pathways in T. thermophila.
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Affiliation(s)
- Hongrui Lv
- School of Life Science, Shanxi University, Taiyuan, 030006, China.,Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Jing Xu
- School of Life Science, Shanxi University, Taiyuan, 030006, China.,Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Tao Bo
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
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8
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Crystal structure of O-Acetylserine sulfhydralase (OASS) isoform 3 from Entamoeba histolytica: Pharmacophore-based virtual screening and validation of novel inhibitors. Eur J Med Chem 2020; 192:112157. [PMID: 32145643 DOI: 10.1016/j.ejmech.2020.112157] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/03/2020] [Accepted: 02/17/2020] [Indexed: 01/09/2023]
Abstract
The l-cysteine is crucial for growth, survival, defense against oxidative stress, and pathogenesis of Entamoeba histolytica. The de novo biosynthesis of l-cysteine in E. histolytica, has a two-step pathway, where O-acetylserine sulfhydrylase (OASS) catalyses the last step by converting OAS to l-cysteine. This pathway is absent in humans and hence represents a promising target for novel therapeutics. E. histolytica expresses three isoforms of OASS and knockdown studies showed the importance of these enzymes for the survival of the pathogen. Here, we report the crystal structure of OASS isoform 3 from E. histolytica to 1.54 Å resolution. The active site geometries and kinetics of EhOASS3 and EhOASS1 structures were found to be very similar. Small-molecule libraries were screened against EhOASS3 and compounds were shortlisted based on the docking scores. F3226-1387 showed best inhibition with IC50 of 38 μM against EhOASS3 and was able to inhibit the growth of the organism to 72%.
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9
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Harun-Ur-Rashid M, Oogai S, Parveen S, Inafuku M, Iwasaki H, Fukuta M, Amzad Hossain M, Oku H. Molecular cloning of putative chloroplastic cysteine synthase in Leucaena leucocephala. JOURNAL OF PLANT RESEARCH 2020; 133:95-108. [PMID: 31828681 DOI: 10.1007/s10265-019-01158-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/02/2019] [Indexed: 05/14/2023]
Abstract
Cysteine biosynthesis is directed by the successive commitments of serine acetyltransferase, and O-acetylserine (thiol) lyase (OASTL) compounds, which subsequently frame the decameric cysteine synthase complex. The isoforms of OASTL are found in three compartments of the cell: the cytosol, plastid, and mitochondria. In this investigation, we first isolated putative chloroplastic OASTL (Ch-OASTL) from Leucaena leucocephala, and the Ch-OASTL was then expressed in BL21-competent Escherichia coli. The putative Ch-OASTL cDNA clone had 1,543 base pairs with 391 amino acids in its open reading frame and a molecular weight of 41.54 kDa. The purified protein product exhibited cysteine synthesis ability, but not mimosine synthesis activity. However, they both make the common α-aminoacrylate intermediate in their first half reaction scheme with the conventional substrate O-acetyl serine (OAS). Hence, we considered putative Ch-OASTL a cysteine-specific enzyme. Kinetic studies demonstrated that the optimum pH for cysteine synthesis was 7.0, and the optimum temperature was 40 °C. In the cysteine synthesis assay, the Km and kcat values were 838 ± 26 µM and 72.83 s-1 for OAS, respectively, and 60 ± 2 µM and 2.43 s-1 for Na2S, respectively. We can infer that putative Ch-OASTL regulatory role is considered a sensor for sulfur constraint conditions, and it acts as a forerunner of various metabolic compound molecules.
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Affiliation(s)
- Md Harun-Ur-Rashid
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
- Department of Genetics and Plant Breeding, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, 1207, Bangladesh
| | - Shigeki Oogai
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
| | - Shahanaz Parveen
- The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, Japan
- Molecular Biotechnology Group, Tropical Biosphere Research Center, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan
- Department of Genetics and Plant Breeding, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, 1207, Bangladesh
| | - Masashi Inafuku
- Molecular Biotechnology Group, Tropical Biosphere Research Center, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan
| | - Hironori Iwasaki
- Molecular Biotechnology Group, Tropical Biosphere Research Center, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan
| | - Masakazu Fukuta
- Department of Subtropical Biochemistry and Biotechnology, Graduate School of Agriculture, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan.
| | - Md Amzad Hossain
- Department of Subtropical Biochemistry and Biotechnology, Graduate School of Agriculture, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan
| | - Hirosuke Oku
- Molecular Biotechnology Group, Tropical Biosphere Research Center, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan
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Devi S, Tarique KF, Ali MF, Abdul Rehman SA, Gourinath S. Identification and characterization of Helicobacter pylori O-acetylserine-dependent cystathionine β-synthase, a distinct member of the PLP-II family. Mol Microbiol 2019; 112:718-739. [PMID: 31132312 DOI: 10.1111/mmi.14315] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2019] [Indexed: 02/02/2023]
Abstract
O-acetylserine sulfhydrylase (OASS) and cystathionine β-synthase (CBS) are members of the PLP-II family, and involved in L-cysteine production. OASS produces L-cysteine via a de novo pathway while CBS participates in the reverse transsulfuration pathway. O-acetylserine-dependent CBS (OCBS) was previously identified as a new member of the PLP-II family, which are predominantly seen in bacteria. The bacterium Helicobacter pylori possess only one OASS (hp0107) gene and we showed that the protein coded by this gene actually functions as an OCBS and utilizes L-homocysteine and O-acetylserine (OAS) to produce cystathionine. HpOCBS did not show CBS activity with the substrate L-serine and required OAS exclusively. The HpOCBS structure in complex with methionine showed a closed cleft state, explaining the initial mode of substrate binding. Sequence and structural analyses showed differences between the active sites of OCBS and CBS, and explain their different substrate preferences. We identified three hydrophobic residues near the active site of OCBS, corresponding to one serine and two tyrosine residues in CBSs. Mutational studies were performed on HpOCBS and Saccharomyces cerevisiae CBS. A ScCBS double mutant (Y158F/Y226V) did not display activity with L-serine, indicating indispensability of these polar residues for selecting substrate L-serine, however, did show activity with OAS.
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Affiliation(s)
- Suneeta Devi
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Khaja Faisal Tarique
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.,Public Health Research Institute, Rutgers, Newark, NJ, USA
| | - Mohammad Farhan Ali
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Syed Arif Abdul Rehman
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.,MRC Protein Phosphorylation & Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Samudrala Gourinath
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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11
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Structural and functional characterisation of phosphoserine phosphatase, that plays critical role in the oxidative stress response in the parasite Entamoeba histolytica. J Struct Biol 2019; 206:254-266. [DOI: 10.1016/j.jsb.2019.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/25/2019] [Accepted: 03/29/2019] [Indexed: 02/02/2023]
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12
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Insights into multifaceted activities of CysK for therapeutic interventions. 3 Biotech 2019; 9:44. [PMID: 30675454 DOI: 10.1007/s13205-019-1572-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 01/10/2019] [Indexed: 01/24/2023] Open
Abstract
CysK (O-acetylserine sulfhydrylase) is a pyridoxal-5' phosphate-dependent enzyme which catalyzes the second step of the de novo cysteine biosynthesis pathway by converting O-acetyl serine (OAS) into l-cysteine in the presence of sulfide. The first step of the cysteine biosynthesis involves formation of OAS from serine and acetyl CoA by CysE (serine acetyltransferase). Apart from role of CysK in cysteine biosynthesis, recent studies have revealed various additional roles of this enzyme in bacterial physiology. Other than the suggested regulatory role in cysteine production, other activities of CysK include involvement of CysK-in contact-dependent toxin activation in Gram-negative pathogens, as a transcriptional regulator of CymR by stabilizing the CymR-DNA interactions, in biofilm formation by providing cysteine and via another mechanism not yet understood, in ofloxacin and tellurite resistance as well as in cysteine desulfurization. Some of these activities involve binding of CysK to another cellular partner, where the complex is regulated by the availability of OAS and/or sulfide (H2S). The aim of this study is to present an overview of current knowledge of multiple functions performed by CysK and identifying structural features involved in alternate functions. Due to possible role in disease, promoting or inhibiting a "moonlighting" function of CysK could be a target for developing novel therapeutic interventions.
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Yeon JY, Yoo SJ, Takagi H, Kang HA. A Novel Mitochondrial Serine O-Acetyltransferase, OpSAT1, Plays a Critical Role in Sulfur Metabolism in the Thermotolerant Methylotrophic Yeast Ogataea parapolymorpha. Sci Rep 2018; 8:2377. [PMID: 29402922 PMCID: PMC5799214 DOI: 10.1038/s41598-018-20630-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/22/2018] [Indexed: 12/03/2022] Open
Abstract
In most bacteria and plants, direct biosynthesis of cysteine from sulfide via O-acetylserine (OAS) is essential to produce sulfur amino acids from inorganic sulfur. Here, we report the functional analysis of a novel mitochondrial serine O-acetyltransferase (SAT), responsible for converting serine into OAS, in the thermotolerant methylotrophic yeast Ogataea parapolymorpha. Domain analysis of O. parapolymorpha SAT (OpSat1p) and other fungal SATs revealed that these proteins possess a mitochondrial targeting sequence (MTS) at the N-terminus and an α/β hydrolase 1 domain at the C-terminal region, which is quite different from the classical SATs of bacteria and plants. Noticeably, OpSat1p is functionally interchangeable with Escherichia coli SAT, CysE, despite that it displays much less enzymatic activity, with marginal feedback inhibition by cysteine, compared to CysE. The Opsat1Δ-null mutant showed remarkably reduced intracellular levels of cysteine and glutathione, implying OAS generation defect. The MTS of OpSat1p directs the mitochondrial targeting of a reporter protein, thus, supporting the localization of OpSat1p in the mitochondria. Intriguingly, the OpSat1p variant lacking MTS restores the OAS auxotrophy, but not the cysteine auxotrophy of the Opsat1Δ mutant strain. This is the first study on a mitochondrial SAT with critical function in sulfur assimilatory metabolism in fungal species.
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Affiliation(s)
- Ji Yoon Yeon
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Su Jin Yoo
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea
| | - Hiroshi Takagi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192, Japan.
| | - Hyun Ah Kang
- Department of Life Science, Chung-Ang University, Seoul, 06974, Korea.
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14
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Devi S, Abdul Rehman SA, Tarique KF, Gourinath S. Structural characterization and functional analysis of cystathionine β-synthase: an enzyme involved in the reverse transsulfuration pathway of Bacillus anthracis. FEBS J 2017; 284:3862-3880. [PMID: 28921884 DOI: 10.1111/febs.14273] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/31/2017] [Accepted: 09/13/2017] [Indexed: 01/29/2023]
Abstract
The reverse transsulfuration pathway has been reported to produce cysteine from homocysteine in eukaryotes ranging from protozoans to mammals while bacteria and plants produce cysteine via a de novo pathway. Interestingly, the bacterium Bacillus anthracis includes enzymes of the reverse transsulfuration pathway viz. cystathionine β-synthase [BaCBS, previously annotated to be an O-acetylserine sulfhydrylase (OASS)] and cystathionine γ-lyase. Here, we report the structure of BaCBS at a resolution of 2.2 Å. The enzyme was found to show CBS activity only with activated serine (O-acetylserine) and not with serine, and was also observed to display OASS activity but not serine sulfhydrylase activity. BaCBS was also found to produce hydrogen sulfide (H2 S) upon reaction of cysteine and homocysteine. A mutational study revealed Glu 220, conserved in CBS, to be necessary for generating H2 S. Structurally, BaCBS display a considerably more open active site than has been found for any other CBS or OASS, which was attributed to the presence of a helix at the junction of the C- and N-terminal domains. The root-mean-square deviation (RMSD) between the backbone Cα carbon atoms of BaCBS and those of other CBSs and OASSs were calculated to be greater than 3.0 Å. The pyridoxal 5'-phosphate at the active site was not traced, and appeared to be highly flexible due to the active site being wide open. Phylogenetic analysis revealed the presence of an O-acetylserine-dependent CBS in the bacterial domain and making separate clade from CBS and OASS indicating its evolution for specific function. DATABASE Structural data are available in the PDB under the accession number 5XW3.
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Affiliation(s)
- Suneeta Devi
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Syed A Abdul Rehman
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.,MRC Protein Phosphorylation & Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Khaja F Tarique
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.,Public Health Research Institute, Rutgers, Newark, NJ, USA
| | - Samudrala Gourinath
- Structural Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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