Engineered Vancomycin, with Increased Interactions with Peptidoglycan Stem Peptide, Conquers Non-tuberculosis...

Area of Science:

• Microbiology
• Drug Discovery
• Structural Biology

Background:

• Vancomycin-class antibiotics target bacterial cell wall synthesis by binding to the D-alanyl-D-alanine terminus of peptidoglycan (PG) precursors.
• Mycobacteria possess a unique PG structure that influences antibiotic susceptibility.
• Optimizing vancomycin binding to PG may overcome resistance mechanisms and enhance efficacy.

Purpose of the Study:

• To engineer a vancomycin derivative with enhanced affinity for mycobacterial peptidoglycan.
• To investigate the structural basis for improved binding.
• To evaluate the antibacterial activity of the engineered vancomycin against mycobacteria.

Main Methods:

• Site-directed mutagenesis of vancomycin to create derivatives with altered binding properties.
• Surface plasmon resonance (SPR) to measure binding affinity to PG stem peptides.
• Minimum inhibitory concentration (MIC) assays to determine antibacterial activity against mycobacteria.

Main Results:

• Engineered vancomycin demonstrated significantly enhanced binding affinity to PG stem peptides containing meso-diaminopimelic acid.
• The enhanced binding is likely due to additional interactions with the third residue of the PG stem.
• The engineered vancomycin exhibited superior bactericidal activity against mycobacteria compared to wild-type vancomycin.

Conclusions:

• Modification of vancomycin to target specific residues in the mycobacterial PG stem peptide can enhance drug affinity.
• This engineered vancomycin shows promise as a potent therapeutic agent against mycobacteria.
• Further development could lead to novel treatments for mycobacterial infections.