Mycothiol redox pathways in Actinobacteria, and beyond

Project Details


In this HOA research project focus will go to the mycothiol reduction pathways in Actinobacteria and to the evaluation of these pathways as possible targets against Mycobacterium tuberculosis. Members of Actinobacteria are Gram-positive bacteria encountered in a wide range of ecosystems and are known to cause important human diseases, such as tuberculosis, diphtheria and Johne's disease in ruminants.

As a starting point, we will investigate arsenate reductases (ArsC) of Actinobacteria. ArsC catalyses the reduction of arsenate to arsenite, and it works together with the components of the thiol/disulphide redox system of cells. Darwinian evolution adopted different protein folds for the reduction of arsenate to arsenite and the coupling to cysteine thiol cascades occurred more than once. This diversity makes arsenate reductases a highly interesting protein family to study the structure/function coupled to different thiol mechanisms.

One of the features common to most Actinobacteria is the production of mycothiol, a small thiol that is often present in millimolar amounts and that has analogous redox homeostasis function to glutathione. Therefore, it is very inspiring to find out how the arsenate reductases in Actinobacteria are possibly linked to mycothiol. At the same time, we will learn which essential proteins are involved in the reduction pathways coupled to mycothiol. As soon as we understand the mycothiol redox pathway, which is specific for Actinobacteria and not present in humans, we can tackle the problem of how to inhibit this pathway. How can we interfere with the redox homeostasis in Actinobacteria? Here the focus will go to the thiol/disulfide pathway of Mycobacterium tuberculosis in order to find new specific drugs against pathogentic bacteria of the Actinobacteria group.

All together, new microbiological and kinetic/mechanistic challenges are embedded within this project. As such, many expertises need to be brought together in order to reach our final goal.

1. Microbiological expertise with Actinobacteria to link arsenate resistance to the ars genes and to the genes of the thiol/disulfide pathway

2. Cloning and protein expression and purification expertise to obtain sufficient amount of recombinant protein

3. Biochemical and enzymology expertise with arsenate reductase and thiol/disulfide pathways to reconstitute the pathways in vitro

4. Expertise with arsenate and arsenite quantifications

5. Mass spectrometry to determine the nature of the recombinantly overexpressed proteins and products formed along the pathway

6. Crystallisation, X-ray crystallography and solving protein structures

7. Theoretical studies to scrutinize the enzyme and/or reacting partners to really understand the catalysis at the molecular level.

8. Syntheses of new small molecule drugs that specific inhibit the mycothiol pathway.

9. Antimicrobial sceening of small molecule drugs.

All the partners and collaborators for this project have been selected based on their specific expertises.
Effective start/end date1/01/1031/12/13


  • Applied Biology

Flemish discipline codes

  • Biological sciences