Unveiling Aziridine-Containing Natural Products by Genomic and Spectroscopic Approaches

Area of Science:

• Natural Product Discovery
• Biochemistry
• Metabolomics

Background:

• Aziridine natural products possess significant bioactivity but are rare and difficult to study.
• Limited understanding of aziridine biosynthesis hinders systematic exploration and drug development.

Purpose of the Study:

• To develop a method for discovering and characterizing aziridine-containing natural products.
• To elucidate the biosynthesis of a novel class of aziridine macrolides.

Main Methods:

• Integrated genome mining with 1H-13C coupled HSQC metabolomics for aziridine detection.
• Utilized genetic and isotopic studies to identify biosynthetic pathways.
• Performed heterologous expression to confirm gene cluster function.
• Employed mass spectrometry to identify enzyme-substrate interactions.

Main Results:

• Discovered the desertolides, macrolides featuring a unique terminal 2-methyl-aziridine-2-carboxylate moiety.
• Identified a dedicated biosynthetic gene cluster (desA-desN) responsible for aziridine assembly and installation from glutamate.
• Characterized DesN, a KAS III homolog, as the first identified aziridine-transferase, covalently binding the aziridine to Cys113.
• Uncovered over 50 potential aziridine biosynthetic gene clusters via bioinformatic analysis.

Conclusions:

• Established a platform for targeted discovery and engineered biosynthesis of aziridine natural products.
• Demonstrated the potential of DesN as a tool for polyketide engineering.
• Highlighted the potential widespread occurrence of aziridine biosynthetic pathways.