Extending the starter-unit selection of a collaborating non-reducing polyketide synthase through rational domain...

Area of Science:

• Biochemistry
• Molecular Biology
• Synthetic Biology

Background:

• Fungal non-reducing polyketide synthases (NR-PKSs) are crucial for producing diverse polyketide compounds.
• Starter-unit acyl transferase (SAT) enzymes play a key role in selecting the initial building block for NR-PKS assembly lines.

Purpose of the Study:

• To investigate the impact of swapping SAT enzymes on the product chain length of fungal NR-PKSs.
• To engineer NR-PKSs for the production of novel polyketides with altered chain lengths.
• To develop a predictive model for NR-PKS product chain length based on SAT activity.

Main Methods:

• Enzyme engineering: Swapping a C6-loading SAT from sorbicillin NR-PKS with an acetyl-loading SAT.
• Characterization of resulting polyketide products to determine chain length and structure.
• Development of a general rule for predicting product chain length after SAT exchange.

Main Results:

• Successful generation of non-native aromatic polyketides with a reduced chain length.
• Demonstrated extension of starter-unit selection capability of NR-PKS to C2 units.
• Established a predictive rule for chain-length control in NR-PKS engineering.

Conclusions:

• SAT engineering is a viable strategy for controlling NR-PKS product chain length.
• This study provides fundamental insights into the modularity and programming of NR-PKS systems.
• The findings open avenues for designing novel polyketides with tailored properties.