Abstract
Mycothiol (MSH) and ergothioneine (ERG) are thiols able to compensate for each other to protect mycobacteria against oxidative stress. Gamma-glutamylcysteine (GGC), another thiol and an intermediate in ERG biosynthesis has detoxification abilities. Five enzymes are involved in ERG biosynthesis, namely EgtA, EgtB, EgtC, EgtD and EgtE. The role of these enzymes in the production of ERG had been unclear. On the other hand, the enzyme MshA is known to be essential for MSH biosynthesis. In this manuscript, we describe the raw data of the generation and characterization of Mycobacterium tuberculosis (M.tb) mutants harbouring a deletion of the gene coding for each of these enzymes, and the raw data of the phenotypic characterization of the obtained thiol-deficient M.tb mutants. High throughput screening (HTS) of off-patent drugs and natural compounds revealed few compounds that displayed a higher activity against the thiol-deficient mutants relative to the wild-type strain. The mode of action of these drugs was further investigated. Raw data displaying these results are described here.
Highlights
Background & SummaryMycothiol (MSH) and ergothioneine (ERG) are the major thiols of actinomycetes[1]
In order to explore the possibility to repurpose off-patent drugs, and in order to explore the potential of natural compounds in a combination therapy with potential drugs that target thiols biosynthesis, we explore the activity of few compounds against the thiol-deficient mutants
As a proof of concept, we investigated the activity of EgtD in the presence of a compound that is known to bind to the S-adenosyl methioneine (SAM) binding pocket of SAM-dependent enzymes[21]
Summary
Mycothiol (MSH) and ergothioneine (ERG) are the major thiols of actinomycetes[1]. In order to better understand the role of these molecules, it is necessary to elucidate their biosynthesis, enzymes involved and the significance of each enzyme in the production of these thiols. In order to relate the role of ERG to MSH, a MSH-deficient mutant was generated through an in frame hygromycin marked deletion of mshA8 (Table 1). In order to explore the potential detoxification role of GGC in M.tb, we investigated the susceptibility of the generated GGC/ERG-deficient ΔegtA mutant relative to the MSH-deficient ΔmshA mutant and the ERG-deficient ΔegtD and ΔegtB mutants in various in vitro stress conditions[8]. Four hits were further expounded on M.tb, namely azaguanine (Aza), sulfaguanidine (Su), bacitracin (Ba) and fusaric acid (Fu) They were tested against thiol-deficient M.tb mutants by growth profiles analysis under the various treatments[9]. Since the general role of thiols is to protect cells against oxidative stress[16], the ability of these compounds to generate oxidative stress (relative to the untreated controls) was evaluated[9]. We were able to investigate the potential activity and mode of action of few compounds against the generated mutants in order to provide a rationale for further investigations into
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