Beta-1,6-glucan synthesis as a novel antifungal drug target

Overview

Fungal infections remain a major health and agricultural challenge, and resistance to current frontline antifungal drugs such as echinocandins is a growing concern. This research proposes beta-1,6-glucan synthesis as a more sensitive and underexplored target for antifungal drug development. Beta-1,6-glucan is a minor but structurally critical component of the fungal cell wall, responsible for organizing and linking the major cell wall polymers. Because it is unique to fungi and absent in human cells, it offers a highly selective therapeutic target with reduced risk of host toxicity.

The team has demonstrated that degrading beta-1,6-glucan with a novel myxobacterial enzyme, GluM, causes more severe damage to fungal cell walls than degrading beta-1,3-glucan or chitin. Genetic knockout studies further confirm that proteins involved in beta-1,6-glucan synthesis are essential for fungal survival, underscoring the pathway's potential as a high-value antifungal target.

Technical specifications

Core discovery:

• A novel membrane-associated beta-1,6-glucanase (GluM) from myxobacteria selectively destroys fungal cell walls
• GluM-induced damage exceeds that caused by beta-1,3-glucanases and chitinases, indicating higher target sensitivity
• Beta-1,6-glucan synthesis genes (including KRE5) are essential, making them attractive drug targets

Planned validation approach:

• Structural characterization of KRE5, the key enzyme in beta-1,6-glucan synthesis, using X-ray crystallization or AlphaFold2-based prediction
• Computational screening of small molecule libraries to identify candidate inhibitors of KRE5
• Chemical synthesis of promising hits and testing for reduction of beta-1,6-glucan content and inhibition of yeast growth using Saccharomyces as a model
• Estimated project duration: approximately one year

Key advantages:

• Addresses the urgent need for new antifungal agents to combat echinocandin-resistant strains
• Target is fungal-specific, reducing potential off-target effects
• Combines structural biology, computational chemistry, and wet-lab validation

Technology readiness level

The concept is currently at an early-to-mid discovery stage. Preliminary experimental evidence supports the biological rationale: GluM enzyme studies and gene knockout data confirm the essential role of beta-1,6-glucan in fungal viability. The next phase involves structural analysis of KRE5, computational inhibitor screening, and synthesis and testing of candidate molecules. The team has established partnerships in chemical synthesis and access to protein crystallization infrastructure, enabling progression toward validated lead compounds within approximately one year. The work is positioned at Technology Readiness Level 3 to 4, transitioning from target validation to candidate identification.