A structural and biochemical model of processive chitin synthesis

Area of Science:

• Biochemistry
• Molecular Biology
• Mycology

Background:

• Chitin synthases (CHS) are crucial for fungal cell wall integrity, but their processive synthesis mechanism remains poorly understood.
• This knowledge gap hinders the development of novel antifungal agents targeting CHS.
• Understanding CHS function is vital for combating fungal infections.

Purpose of the Study:

• To elucidate the molecular mechanism and structure of chitin synthases (CHS).
• To establish a platform for discovering new inhibitors targeting fungal CHS.
• To utilize the bacterial glycosyltransferase NodC as a model for CHS research.

Main Methods:

• Developed a novel high-throughput screening-compatible assay.
• Employed mutagenesis to probe the catalytic mechanism of NodC.
• Mapped the membrane topology of NodC.
• Utilized a structural model of NodC based on the BcsA cellulose synthase structure.

Main Results:

• A known fungal CHS inhibitor was found to inhibit NodC.
• Mutagenesis confirmed the essential roles of the DD and QXXRW catalytic motifs in NodC.
• The structural and topological data validated the NodC model.
• The study provides insights into CHS structure and mechanism.

Conclusions:

• Bacterial NodC serves as a suitable model for studying chitin synthase (CHS) structure and mechanism.
• The identified catalytic motifs are critical for enzyme function.
• This research establishes a foundation for developing targeted antifungal therapies by enabling inhibitor discovery.