Protein Cofactor Mimics Disrupt Essential Chaperone Function in Stressed Mycobacteria

Area of Science:

• Molecular Biology
• Structural Biology
• Drug Discovery

Background:

• Bacterial DnaK is an ATP-dependent molecular chaperone crucial for protein homeostasis (proteostasis).
• DnaJ cofactors deliver substrates to DnaK and activate its ATPase activity for protein folding.
• In Mycobacterium tuberculosis, DnaK interacts with DnaJ1 and DnaJ2; these interactions are vital for survival.

Purpose of the Study:

• To design and synthesize peptide-based inhibitors targeting the DnaK-DnaJ interaction.
• To evaluate the efficacy of these inhibitors against Mycobacterium tuberculosis proteotoxic stress.

Main Methods:

• Synthesis of peptide mimetics mimicking DnaJ1 and DnaJ2 N-terminal domains.
• In vitro assays to assess the disruption of DnaK-cofactor activity.
• In vivo experiments to evaluate the impact on mycobacterial recovery from proteotoxic stress.

Main Results:

• Covalently stabilized DnaJ mimetics effectively disrupted DnaK-cofactor activity in vitro.
• These mimetics prevented Mycobacterium tuberculosis recovery from proteotoxic stress in vivo.
• The inhibition resulted in mycobacterial cell death, demonstrating antibacterial potential.

Conclusions:

• Peptide-based DnaJ mimetics are effective inhibitors of essential DnaK-cofactor interactions.
• Targeting these conserved chaperone-cofactor interactions represents a promising antibacterial strategy.
• The findings can guide the development of novel therapeutics for various cell types.