Structure of Trypanosoma brucei glutathione synthetase: domain and loop alterations in the catalytic cycle of a highly conserved enzyme

Paul K. Fyfe, Magnus S. Alphey, William N. Hunter

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    9 Citations (Scopus)

    Abstract

    Glutathione synthetase catalyses the synthesis of the low molecular mass thiol glutathione from L-gamma-glutamyl-L-cysteine and glycine. We report the crystal structure of the dimeric enzyme from Trypanosoma brucei in complex with the product glutathione. The enzyme belongs to the ATP-grasp family, a group of enzymes known to undergo conformational changes upon ligand binding. The T brucei enzyme crystal structure presents two dimers in the asymmetric unit. The structure reveals variability in the order and position of a small domain, which forms a lid for the active site and serves to capture conformations likely to exist during the catalytic cycle. Comparisons with orthologous enzymes, in particular from Homo sapiens and Saccharomyces cerevisae, indicate a high degree of sequence and structure conservation in part of the active site. Structural differences that are observed between the orthologous enzymes are assigned to different ligand binding states since key residues are conserved. This suggests that the molecular determinants of ligand recognition and reactivity are highly conserved across species. We conclude that it would be difficult to target the parasite enzyme in preference to the host enzyme and therefore glutathione synthetase may not be a suitable target for antiparasitic drug discovery. (C) 2010 Elsevier B.V. All rights reserved.

    Original languageEnglish
    Pages (from-to)93-99
    Number of pages7
    JournalMolecular and Biochemical Parasitology
    Volume170
    Issue number2
    DOIs
    Publication statusPublished - Apr 2010

    Keywords

    • ATP-grasp
    • Glutathione
    • Glutathione synthetase
    • Trypanosoma brucei
    • Trypanothione
    • X-ray structure
    • ESCHERICHIA-COLI-B
    • CRYSTAL-STRUCTURE
    • TRYPANOTHIONE SYNTHETASE
    • CRITHIDIA-FASCICULATA
    • ANGSTROM RESOLUTION
    • REDUCTASE
    • PROTEINS
    • DISCOVERY
    • ALIGNMENT
    • REVEALS

    Cite this

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    title = "Structure of Trypanosoma brucei glutathione synthetase: domain and loop alterations in the catalytic cycle of a highly conserved enzyme",
    abstract = "Glutathione synthetase catalyses the synthesis of the low molecular mass thiol glutathione from L-gamma-glutamyl-L-cysteine and glycine. We report the crystal structure of the dimeric enzyme from Trypanosoma brucei in complex with the product glutathione. The enzyme belongs to the ATP-grasp family, a group of enzymes known to undergo conformational changes upon ligand binding. The T brucei enzyme crystal structure presents two dimers in the asymmetric unit. The structure reveals variability in the order and position of a small domain, which forms a lid for the active site and serves to capture conformations likely to exist during the catalytic cycle. Comparisons with orthologous enzymes, in particular from Homo sapiens and Saccharomyces cerevisae, indicate a high degree of sequence and structure conservation in part of the active site. Structural differences that are observed between the orthologous enzymes are assigned to different ligand binding states since key residues are conserved. This suggests that the molecular determinants of ligand recognition and reactivity are highly conserved across species. We conclude that it would be difficult to target the parasite enzyme in preference to the host enzyme and therefore glutathione synthetase may not be a suitable target for antiparasitic drug discovery. (C) 2010 Elsevier B.V. All rights reserved.",
    keywords = "ATP-grasp, Glutathione, Glutathione synthetase, Trypanosoma brucei, Trypanothione, X-ray structure, ESCHERICHIA-COLI-B, CRYSTAL-STRUCTURE, TRYPANOTHIONE SYNTHETASE, CRITHIDIA-FASCICULATA, ANGSTROM RESOLUTION, REDUCTASE, PROTEINS, DISCOVERY, ALIGNMENT, REVEALS",
    author = "Fyfe, {Paul K.} and Alphey, {Magnus S.} and Hunter, {William N.}",
    year = "2010",
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    doi = "10.1016/j.molbiopara.2009.12.011",
    language = "English",
    volume = "170",
    pages = "93--99",
    journal = "Molecular and Biochemical Parasitology",
    issn = "0166-6851",
    publisher = "Elsevier",
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    }

    TY - JOUR

    T1 - Structure of Trypanosoma brucei glutathione synthetase

    T2 - domain and loop alterations in the catalytic cycle of a highly conserved enzyme

    AU - Fyfe, Paul K.

    AU - Alphey, Magnus S.

    AU - Hunter, William N.

    PY - 2010/4

    Y1 - 2010/4

    N2 - Glutathione synthetase catalyses the synthesis of the low molecular mass thiol glutathione from L-gamma-glutamyl-L-cysteine and glycine. We report the crystal structure of the dimeric enzyme from Trypanosoma brucei in complex with the product glutathione. The enzyme belongs to the ATP-grasp family, a group of enzymes known to undergo conformational changes upon ligand binding. The T brucei enzyme crystal structure presents two dimers in the asymmetric unit. The structure reveals variability in the order and position of a small domain, which forms a lid for the active site and serves to capture conformations likely to exist during the catalytic cycle. Comparisons with orthologous enzymes, in particular from Homo sapiens and Saccharomyces cerevisae, indicate a high degree of sequence and structure conservation in part of the active site. Structural differences that are observed between the orthologous enzymes are assigned to different ligand binding states since key residues are conserved. This suggests that the molecular determinants of ligand recognition and reactivity are highly conserved across species. We conclude that it would be difficult to target the parasite enzyme in preference to the host enzyme and therefore glutathione synthetase may not be a suitable target for antiparasitic drug discovery. (C) 2010 Elsevier B.V. All rights reserved.

    AB - Glutathione synthetase catalyses the synthesis of the low molecular mass thiol glutathione from L-gamma-glutamyl-L-cysteine and glycine. We report the crystal structure of the dimeric enzyme from Trypanosoma brucei in complex with the product glutathione. The enzyme belongs to the ATP-grasp family, a group of enzymes known to undergo conformational changes upon ligand binding. The T brucei enzyme crystal structure presents two dimers in the asymmetric unit. The structure reveals variability in the order and position of a small domain, which forms a lid for the active site and serves to capture conformations likely to exist during the catalytic cycle. Comparisons with orthologous enzymes, in particular from Homo sapiens and Saccharomyces cerevisae, indicate a high degree of sequence and structure conservation in part of the active site. Structural differences that are observed between the orthologous enzymes are assigned to different ligand binding states since key residues are conserved. This suggests that the molecular determinants of ligand recognition and reactivity are highly conserved across species. We conclude that it would be difficult to target the parasite enzyme in preference to the host enzyme and therefore glutathione synthetase may not be a suitable target for antiparasitic drug discovery. (C) 2010 Elsevier B.V. All rights reserved.

    KW - ATP-grasp

    KW - Glutathione

    KW - Glutathione synthetase

    KW - Trypanosoma brucei

    KW - Trypanothione

    KW - X-ray structure

    KW - ESCHERICHIA-COLI-B

    KW - CRYSTAL-STRUCTURE

    KW - TRYPANOTHIONE SYNTHETASE

    KW - CRITHIDIA-FASCICULATA

    KW - ANGSTROM RESOLUTION

    KW - REDUCTASE

    KW - PROTEINS

    KW - DISCOVERY

    KW - ALIGNMENT

    KW - REVEALS

    U2 - 10.1016/j.molbiopara.2009.12.011

    DO - 10.1016/j.molbiopara.2009.12.011

    M3 - Article

    C2 - 20045436

    VL - 170

    SP - 93

    EP - 99

    JO - Molecular and Biochemical Parasitology

    JF - Molecular and Biochemical Parasitology

    SN - 0166-6851

    IS - 2

    ER -