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Updated: Jul 19, 2025
Achieving Efficient Fragment Screening at XChem Facility at Diamond Light Source
Published on: May 29, 2021
Novel starting points for fragment-based drug design against mycobacterial thioredoxin reductase identified using
Friederike T Füsser1, Jan Wollenhaupt2, Manfred S Weiss2
1Institute of Pharmaceutical and Medicinal Chemistry, Münster University, Corrensstrasse 48, 48149 Münster, Germany.
Abstract:
The increasing number of people dying from tuberculosis and the existence of extensively drug-resistant strains has led to an urgent need for new antituberculotic drugs with alternative modes of action. As part of the thioredoxin system, thioredoxin reductase (TrxR) is essential for the survival of Mycobacterium tuberculosis (Mtb) and shows substantial differences from human TrxR, making it a promising and most likely selective target. As a model organism for Mtb, crystals of Mycobacterium smegmatis TrxR that diffracted to high resolution were used in crystallographic fragment screening to discover binding fragments and new binding sites. The application of the 96 structurally diverse fragments from the F2X-Entry Screen revealed 56 new starting points for fragment-based drug design of new TrxR inhibitors. Over 200 crystal structures were analyzed using FragMAXapp, which includes processing and refinement by largely automated software pipelines and hit identification via the multi-data-set analysis approach PanDDA. The fragments are bound to 11 binding sites, of which four are positioned at binding pockets or important interaction sites and therefore show high potential for possible inhibition of TrxR.
Insights
New antitubercular drugs are needed due to drug resistance. Researchers identified potential drug targets by screening Mycobacterium smegmatis thioredoxin reductase (TrxR) for binding fragments, revealing new avenues for tuberculosis treatment.
Area of Science:
- Biochemistry
- Structural Biology
- Drug Discovery
Background:
- Tuberculosis (TB) poses a growing global health threat, exacerbated by extensively drug-resistant strains.
- Novel antitubercular drugs with alternative mechanisms of action are urgently required.
- Thioredoxin reductase (TrxR) is crucial for Mycobacterium tuberculosis (Mtb) survival and presents a selective drug target due to its differences from human TrxR.
Purpose of the Study:
- To identify novel binding fragments and sites on Mycobacterium smegmatis TrxR (a model for Mtb TrxR) using crystallographic fragment screening.
- To discover new starting points for fragment-based drug design of selective TrxR inhibitors.
- To analyze crystal structures for potential inhibition sites on Mtb TrxR.
Main Methods:
- High-resolution crystallography was employed on Mycobacterium smegmatis TrxR crystals.
- Fragment screening utilized 96 structurally diverse fragments from the F2X-Entry Screen.
- Automated software pipelines (FragMAXapp) and PanDDA were used for structure processing, refinement, and hit identification, analyzing over 200 crystal structures.
Main Results:
- Fragment screening identified 56 potential starting points for fragment-based drug design.
- Fragments bound to 11 distinct sites on the M. smegmatis TrxR.
- Four identified binding sites are located in pockets or crucial interaction areas, indicating high potential for TrxR inhibition.
Conclusions:
- Crystallographic fragment screening of M. smegmatis TrxR successfully identified numerous binding fragments and sites.
- These findings provide a strong foundation for developing novel, selective inhibitors targeting Mtb TrxR.
- The identified fragments and sites offer promising leads for new antitubercular drug discovery.
