Expanding the molecular landscape of fragments binding to trypanothione reductase, a legitimate target for drug design against human African trypanosomiasis

Crystallographic fragment screening is a powerful methodology that enables the identification of low molecular weight ligands and has shown great promises in drug discovery. In this work we report the results of a fragment screening carried out in an effort to further map the cavities of trypanothio...

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Main Authors: Cécile Exertier, Lorenzo Antonelli, Vittorio Brufani, Gianni Colotti, Andrea Ilari, Annarita Fiorillo
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Chemical Biology
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Online Access:https://www.frontiersin.org/articles/10.3389/fchbi.2025.1605579/full
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author Cécile Exertier
Lorenzo Antonelli
Vittorio Brufani
Gianni Colotti
Andrea Ilari
Annarita Fiorillo
Annarita Fiorillo
author_facet Cécile Exertier
Lorenzo Antonelli
Vittorio Brufani
Gianni Colotti
Andrea Ilari
Annarita Fiorillo
Annarita Fiorillo
author_sort Cécile Exertier
collection DOAJ
description Crystallographic fragment screening is a powerful methodology that enables the identification of low molecular weight ligands and has shown great promises in drug discovery. In this work we report the results of a fragment screening carried out in an effort to further map the cavities of trypanothione reductase from Trypanosoma brucei (TbTR), a critical target for drug design against human African trypanosomiases (HAT), for which efficient and non-toxic trypanocidal drugs are lacking. Moreover, the conservation of trypanothione reductase among trypanosomatids, including Leishmania, could facilitate the design of a wide-spectrum drug against many parasitic diseases. At the XCHEM facility (Diamond Light Sources, United Kingdom) we performed the soaking of TbTR monoclinic crystals with fragments from DSIpoised and EubOPEN DSIp libraries and we identified eight new hits binding to different cavities of TR including the trypanothione and the NADPH binding cavities. These fragments exhibited affinities ranging from submillimolar to millimolar, as determined by surface plasmon resonance (SPR). While the newly identified fragments did not significantly alter TbTR’s enzymatic activity—consistent with the nature of low-affinity ligands—they provide valuable insights into key interactions of fragments with TR and, together with prior fragment screening campaigns, pave the way towards follow-up chemical optimization into lead compounds.
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spelling doaj-art-5c3f5972b1e449fbbed011ab955e8a6c2025-08-20T03:09:48ZengFrontiers Media S.A.Frontiers in Chemical Biology2813-530X2025-05-01410.3389/fchbi.2025.16055791605579Expanding the molecular landscape of fragments binding to trypanothione reductase, a legitimate target for drug design against human African trypanosomiasisCécile Exertier0Lorenzo Antonelli1Vittorio Brufani2Gianni Colotti3Andrea Ilari4Annarita Fiorillo5Annarita Fiorillo6Institute of Molecular Biology and Pathology, Italian National Research Council (IBPM-CNR), c/o Department Biochemical Sciences, Sapienza University of Rome, Rome, ItalyInstitute of Molecular Biology and Pathology, Italian National Research Council (IBPM-CNR), c/o Department Biochemical Sciences, Sapienza University of Rome, Rome, ItalyDepartment Biochemical Sciences, Sapienza University of Rome, Rome, ItalyInstitute of Molecular Biology and Pathology, Italian National Research Council (IBPM-CNR), c/o Department Biochemical Sciences, Sapienza University of Rome, Rome, ItalyInstitute of Molecular Biology and Pathology, Italian National Research Council (IBPM-CNR), c/o Department Biochemical Sciences, Sapienza University of Rome, Rome, ItalyInstitute of Molecular Biology and Pathology, Italian National Research Council (IBPM-CNR), c/o Department Biochemical Sciences, Sapienza University of Rome, Rome, ItalyDepartment Biochemical Sciences, Sapienza University of Rome, Rome, ItalyCrystallographic fragment screening is a powerful methodology that enables the identification of low molecular weight ligands and has shown great promises in drug discovery. In this work we report the results of a fragment screening carried out in an effort to further map the cavities of trypanothione reductase from Trypanosoma brucei (TbTR), a critical target for drug design against human African trypanosomiases (HAT), for which efficient and non-toxic trypanocidal drugs are lacking. Moreover, the conservation of trypanothione reductase among trypanosomatids, including Leishmania, could facilitate the design of a wide-spectrum drug against many parasitic diseases. At the XCHEM facility (Diamond Light Sources, United Kingdom) we performed the soaking of TbTR monoclinic crystals with fragments from DSIpoised and EubOPEN DSIp libraries and we identified eight new hits binding to different cavities of TR including the trypanothione and the NADPH binding cavities. These fragments exhibited affinities ranging from submillimolar to millimolar, as determined by surface plasmon resonance (SPR). While the newly identified fragments did not significantly alter TbTR’s enzymatic activity—consistent with the nature of low-affinity ligands—they provide valuable insights into key interactions of fragments with TR and, together with prior fragment screening campaigns, pave the way towards follow-up chemical optimization into lead compounds.https://www.frontiersin.org/articles/10.3389/fchbi.2025.1605579/fulltrypanothione reductasefragment screeningprotein crystallographysurface plasmon resonancedrug discovery
spellingShingle Cécile Exertier
Lorenzo Antonelli
Vittorio Brufani
Gianni Colotti
Andrea Ilari
Annarita Fiorillo
Annarita Fiorillo
Expanding the molecular landscape of fragments binding to trypanothione reductase, a legitimate target for drug design against human African trypanosomiasis
Frontiers in Chemical Biology
trypanothione reductase
fragment screening
protein crystallography
surface plasmon resonance
drug discovery
title Expanding the molecular landscape of fragments binding to trypanothione reductase, a legitimate target for drug design against human African trypanosomiasis
title_full Expanding the molecular landscape of fragments binding to trypanothione reductase, a legitimate target for drug design against human African trypanosomiasis
title_fullStr Expanding the molecular landscape of fragments binding to trypanothione reductase, a legitimate target for drug design against human African trypanosomiasis
title_full_unstemmed Expanding the molecular landscape of fragments binding to trypanothione reductase, a legitimate target for drug design against human African trypanosomiasis
title_short Expanding the molecular landscape of fragments binding to trypanothione reductase, a legitimate target for drug design against human African trypanosomiasis
title_sort expanding the molecular landscape of fragments binding to trypanothione reductase a legitimate target for drug design against human african trypanosomiasis
topic trypanothione reductase
fragment screening
protein crystallography
surface plasmon resonance
drug discovery
url https://www.frontiersin.org/articles/10.3389/fchbi.2025.1605579/full
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