Mechanism of action of nikkomycin and the peptide transport system of Candida albicans.

Nikkomycin was found to be a potent growth inhibitor of Candida albicans through competitive inhibition of chitin synthase [Ki = 0.16 microM (0.1 microgram ml-1)]. The activity of the peptide-nucleoside drug was antagonized by both peptone and defined peptides. Transported dipeptides were effective antagonists while transported oligopeptides were not. A mutant of C. albicans resistant to the effects of nikkomycin through a transport defect was unable to transport dipeptides, while oligopeptide uptake was apparently unaffected. At least two peptide permeases are operational in this organism.