A Comprehensive Structural and Functional Analysis of Saccharomyces Killer Toxins

Area of Science:

• Biochemistry and Molecular Biology
• Mycology
• Structural Biology

Background:

• Antifungal killer toxins are crucial for combating fungal pathogens affecting human health and agriculture.
• Limited empirical tertiary structures hinder understanding of killer toxin mechanisms and pathogen targeting.

Purpose of the Study:

• To generate tertiary structure models for canonical Saccharomyces killer toxins using computational approaches.
• To predict functional domains, post-translational modifications, and mechanisms of action for these toxins.
• To identify novel antifungal agents by characterizing unstudied killer toxins and their homologs.

Main Methods:

• Utilized AlphaFold and molecular dynamics simulations to create tertiary structure models of Saccharomyces killer toxins.
• Analyzed structural homology to well-studied toxins (K1, K2) and other protein families (aerolysins, lectins).
• Integrated structural data with existing empirical and sequence data for functional predictions.

Main Results:

• Successfully modeled tertiary structures, predicting functional domains and post-translational modifications (proteolytic cleavage, disulfide bonds).
• Revealed unexpected homology among Saccharomyces killer toxins, suggesting most function as ionophores.
• Identified structural similarities of understudied toxins (Klus, KHR, K62) to bacterial/plant toxins, providing insights into their mechanisms.

Conclusions:

• Computational modeling provides a powerful approach to characterize Saccharomyces killer toxins and predict their functions.
• Structural insights suggest potential for novel antifungal agents derived from killer toxin homologs across fungi.
• This work facilitates the development of new strategies against fungal infections in medicine and agriculture.