Targeted Small-Molecule Inhibitors of Trehalose-6-Phosphate Synthase for Antimicrobial and Antifungal Applications

Overview

Trehalose-6-phosphate synthase (TPS) is a validated drug target found in bacteria, fungi, and invertebrates but absent in vertebrates and distinct in plants. This research program focuses on discovering and designing small-molecule inhibitors that selectively bind to prokaryotic and fungal TPS enzymes while sparing plant TPS, enabling safe application as antimicrobial drugs or agricultural fungicides. The team has solved high-resolution crystal structures of the fungal TPS from Magnaporthe oryzae (MoTps1), a key virulence factor in rice blast disease, as well as the bacterial OtsA enzyme from Escherichia coli (EcOtsA). These structural insights have already yielded two lead compounds with higher binding affinity than natural substrates, and a DNA-encoded library (DEL) screen of approximately 4.4 billion compounds has produced dozens of additional selective candidates.

Technical specifications

Core approach:

• Structure-based drug design using solved crystal structures of MoTps1 and EcOtsA, including substrate-bound complexes that reveal catalytic mechanism
• Selectivity screening against plant TPS enzymes (rice and Arabidopsis) as negative controls to ensure safety for agricultural use
• DNA-encoded library screening through partnership with Wuxi AppTec, covering ~4.4 billion compounds

Current candidates:

• Two compounds confirmed to bind MoTps1 with higher affinity than its natural substrates
• Tens of additional candidates identified with binding specificity to MoTps1, EcOtsA, or both
• Best candidates being prepared for downstream biochemical and structural validation

Planned validation assays:

• Affinity measurement and enzyme activity inhibition assays
• Co-crystallization and structure determination to elucidate binding mechanism
• Selectivity profiling against plant TPS enzymes

Technology readiness level

The program is at an early-to-mid stage of preclinical discovery (TRL 3–4). Structural biology foundations are complete, initial hit identification has been achieved through both rational design and DEL screening, and a contract with Wuxi AppTec is in place for candidate preparation. The next 1–2 years will focus on hit-to-lead optimization, mechanism-of-action studies, and selectivity confirmation. The team is actively seeking partners who can contribute medicinal chemistry expertise for compound design and synthesis, as well as funding to support ongoing optimization efforts.