Enzymatic Targets in Mycobacterial Drug Discovery

Mycobacterium tuberculosis remains a leading cause of infectious mortality worldwide, driving efforts to identify and exploit essential enzymatic processes for therapeutic intervention. Central to the pathogen’s survival is the construction and maintenance of its complex cell envelope, which comprises peptidoglycan, arabinogalactan and mycolic acids. Enzymes involved in these biosynthetic pathways – such as the Mur ligases that assemble peptidoglycan precursors, alanine racemase and D-alanine:D-alanine ligase responsible for d-alanine incorporation, and glutamate racemase catalysing the production of d-glutamate – have emerged as high-value targets. Beyond cell wall biogenesis, secretory enzymes and protein kinases that regulate cell division and stress responses provide alternative opportunities to overcome drug resistance. Recent advances in structural biology, enzymology and chemical screening have refined our understanding of catalytic mechanisms, revealed allosteric sites and enabled the design of inhibitors with increased potency and specificity. Collectively, these efforts have yielded lead compounds that disrupt cell wall integrity, attenuate virulence and restore activity against resistant strains, underlining the global significance and translational potential of enzyme-focused strategies in anti-tubercular drug discovery.

Research from Nature Portfolio

Recent studies have illuminated mechanistic details of existing antibiotics and discovered novel inhibitors through combinatorial and computational approaches. Structural and kinetic analyses of a second-line agent revealed that its inhibition of D-alanine:D-alanine ligase proceeds via an unexpected phosphorylated intermediate, providing a blueprint for bimodal inhibitor design that targets multiple active-site conformations. Complementing this, high-throughput virtual screening of natural product libraries pinpointed flavonoid molecules that bind to glutamate racemase with submicromolar affinity, inducing conformational changes that compromise cell wall assembly. Subsequent biochemical and microscopic assays confirmed these compounds’ capacity to perturb membrane integrity in mycobacteria, marking a promising starting point for the development of plant-derived antitubercular leads.

Enzymatic Targets in Mycobacterial Drug Discovery publication trend

The graph below shows the total number of articles in enzymatic targets in mycobacterial drug discovery across all publications each year (not limited to Nature Index journals).

Technical terms

Peptidoglycan: A polymer of sugars and amino acids forming the rigid framework of the bacterial cell wall.

Mur ligases: A family of ATP-dependent enzymes (MurC-MurF) that sequentially assemble the peptide stems of peptidoglycan precursors.

Glutamate racemase (MurI): An enzyme that catalyses the interconversion of l-glutamate to d-glutamate, an essential component of peptidoglycan.

D-Alanine:D-alanine ligase (Ddl): An ATP-grasp enzyme that forms the d-alanine dipeptide required for cross-linking peptidoglycan strands.

Lipoarabinomannan: A complex glycolipid in the mycobacterial cell envelope implicated in host–pathogen interactions and immune modulation.

References

1. Emerging Extracellular Molecular Targets for Innovative Pharmacological Approaches to Resistant Mtb Infection. Biomolecules (2023).
2. Inhibition of D-Ala:D-Ala ligase through a phosphorylated form of the antibiotic D-cycloserine. Nature Communications (2017).
3. Characterisation of ATP-Dependent Mur Ligases Involved in the Biogenesis of Cell Wall Peptidoglycan in Mycobacterium tuberculosis. PLOS ONE (2013).
4. Screening of natural compounds that targets glutamate racemase of Mycobacterium tuberculosis reveals the anti-tubercular potential of flavonoids. Scientific Reports (2020).
5. Glutamate Racemase Is the Primary Target of β-Chloro-d-Alanine in Mycobacterium tuberculosis. Antimicrobial Agents and Chemotherapy (2016).