Structure-activity relationships of the nikkomycins

Area of Science:

• Biochemistry
• Molecular Biology
• Mycology

Background:

• Nikkomycins are nucleoside-peptide antibiotics with antifungal properties.
• Chitin synthase is a crucial enzyme in fungal cell wall biosynthesis.
• Understanding structure-activity relationships is key to developing potent inhibitors.

Purpose of the Study:

• To elucidate the structural requirements for potent nikkomycin inhibition of chitin synthase.
• To investigate the role of the peptide transport system in nikkomycin uptake.
• To assess the impact of structural modifications on nikkomycin stability and activity.

Main Methods:

• Studied structure-activity relationships of various nikkomycins.
• Investigated nikkomycin transport using the peptide transport system in *Yarrowia lipolytica*.
• Determined kinetic parameters for nikkomycin Z uptake.
• Assessed susceptibility to fungal peptidase activity.

Main Results:

• Determined kinetic parameters for nikkomycin Z uptake: Km = 24 microM, Vmax = 2.2 nmol min-1 (mg dry wt)-1.
• Demonstrated that the beta-methyl group on the N-terminal amino acid of dipeptide nikkomycins confers protection against peptidase activity.
• Established a relationship between chitin synthase inhibition, peptide transport, protease susceptibility, and whole-cell activity.

Conclusions:

• Structural features, particularly the N-terminal beta-methyl group, are critical for nikkomycin efficacy.
• The peptide transport system plays a significant role in nikkomycin uptake.
• Optimized nikkomycin structures can lead to enhanced antifungal agents.