Functional analysis of the aureothin iterative type I polyketide synthase

Area of Science:

• Biochemistry
• Molecular Biology
• Synthetic Biology

Background:

• Polyketide synthases (PKS) are crucial for producing diverse natural products.
• The aureothin (aur) PKS is a rare example of iterative PKS module usage.
• Understanding PKS modularity is key to engineering novel compounds.

Purpose of the Study:

• To provide unequivocal evidence for the iterative function of the AurA PKS module.
• To investigate the role of aureothin PKS module 4 in polyketide biosynthesis.
• To characterize the function of an aberrant acyltransferase domain in PKS module 4.

Main Methods:

• Heterologous expression of an engineered AurAB fusion protein.
• Site-directed mutagenesis of the aureothin PKS genes.
• Analysis of polyketide products from engineered strains.

Main Results:

• The engineered AurAB fusion protein confirmed the iterative mechanism of the AurA module.
• Point mutations demonstrated the participation of PKS module 4 in aureothin biosynthesis.
• Aberrant acyltransferase domain in module 4 does not abolish its function.

Conclusions:

• The study provides strong evidence for iterative PKS module function in aureothin biosynthesis.
• Aureothin PKS module 4 contributes to polyketide chain elongation despite its unusual domain.
• Findings advance the understanding of PKS diversity and engineering potential.