ABSTRACTThe lack of effective therapies for treating tuberculosis (TB) is a global health problem. WhileMycobacterium tuberculosisis notoriously resistant to most available antibiotics, we identified synthetic short cationic antimicrobial peptides that were active at low micromolar concentrations (less than 10 μM). These small peptides (averaging 10 amino acids) had remarkably broad spectra of antimicrobial activities against both bacterial and fungal pathogens and an indication of low cytotoxicity. In addition, their antimicrobial activities displayed various degrees of species specificity that were not related to taxonomy. For example,Candida albicansandStaphylococcus aureuswere the best surrogates to predict peptide activity againstM. tuberculosis, whileMycobacterium smegmatiswas a poor surrogate. Principle component analysis of activity spectrum profiles identified unique features associated with activity againstM. tuberculosisthat reflect their distinctive amino acid composition; active peptides were more hydrophobic and cationic, reflecting increased tryptophan with compensating decreases in valine and other uncharged amino acids and increased lysine. These studies provide foundations for development of cationic antimicrobial peptides as potential new therapeutic agents for TB treatment.
The Two-Domain LysX Protein of Mycobacterium tuberculosis Is Required for Production of Lysinylated Phosphatidylglycerol and Resistance to Cationic Antimicrobial Peptides
