Structural and functional analysis of EntV reveals a 12 amino acid fragment protective against fungal infections

Area of Science:

• Microbiology
• Biochemistry
• Drug Discovery

Background:

• Fungal infections pose a significant global health threat due to limited effective treatments and increasing antifungal resistance.
• The bacteriocin EntV from Enterococcus faecalis has previously demonstrated inhibition of Candida albicans virulence.
• Optimization of EntV is crucial for developing novel antifungal therapeutics.

Purpose of the Study:

• To elucidate the structural basis of EntV's antifungal activity.
• To identify and characterize the minimal active antifungal component of EntV.
• To evaluate the therapeutic potential of EntV-derived peptides against various fungal pathogens.

Main Methods:

• X-ray crystallography was employed to determine the three-dimensional structure of EntV.
• Individual alpha helices of EntV were synthesized and tested for antifungal activity in vitro.
• Antifungal efficacy was assessed using nematode infection models and rodent infection models (oropharyngeal, systemic, and catheter-associated).
• Activity against Candida auris and Cryptococcus neoformans was also evaluated.

Main Results:

• The X-ray structure revealed EntV comprises seven alpha helices, with a central 16-amino acid helix (α7).
• The α7 peptide demonstrated significant antifungal activity against Candida albicans, but lacked antibacterial properties.
• α7 was also effective against other resistant fungi, including Candida auris and Cryptococcus neoformans.
• A truncated 12-amino acid version of α7 retained full antifungal potency.
• EntV-derived peptides showed excellent efficacy in preclinical rodent models of C. albicans infections.

Conclusions:

• The seventh alpha helix (α7) of EntV is the primary antifungal domain.
• EntV-derived peptides, particularly the truncated α7, represent promising candidates for developing new antifungal therapies.
• These peptides exhibit broad-spectrum activity against clinically relevant fungal pathogens and are effective in vivo.