Engineering anthracycline biosynthesis toward angucyclines

Area of Science:

• Microbiology
• Biochemistry
• Synthetic Biology

Background:

• Anthracyclines are a class of antibiotics with significant clinical applications.
• Understanding and manipulating their biosynthesis pathways can lead to novel analogs.
• Angucyclines represent a distinct subclass of anthracyclines with unique structural features.

Purpose of the Study:

• To redirect anthracycline biosynthesis towards angucyclines using a specific cyclase.
• To investigate the substrate flexibility of the angucycline-specific cyclase pgaF.
• To engineer novel angucyclinone metabolites.

Main Methods:

• Isolation of the angucycline-specific cyclase pgaF from a silent gene cluster.
• Construction of a gene cassette containing early biosynthesis genes of nogalamycin.
• Modification of the gene cassette with aclacinomycin biosynthesis genes (aknE2 and aknF) to test pgaF substrate flexibility.

Main Results:

• Addition of pgaF to the nogalamycin gene cassette produced known angucyclinones: rabelomycin and its precursor UWM6.
• Replacement of nogalamycin genes with aclacinomycin genes and pgaF yielded a novel angucyclinone, MM2002.
• MM2002 incorporated an ethyl side chain into its fourth ring, demonstrating pgaF's ability to accept altered substrates.

Conclusions:

• The angucycline-specific cyclase pgaF can redirect anthracycline biosynthesis pathways.
• pgaF exhibits substrate flexibility, enabling the production of novel angucyclinone structures.
• This study provides a foundation for engineering diverse angucyclinone antibiotics.