Interrogating the molecular basis for multiple macrolactone ring formation by the pikromycin polyketide synthase

Area of Science:

• Biochemistry
• Molecular Biology
• Synthetic Biology

Background:

• The pikromycin polyketide synthase (PKS) exhibits unique dual-ring macrolactone synthesis.
• Understanding the molecular basis of PKS metabolic diversity is key for expanding chemical libraries.

Purpose of the Study:

• To investigate the role of protein-protein interactions between PikAIII and PikAIV in 12-membered macrolactone production.
• To elucidate the mechanism of metabolic diversity control in modular PKS.

Main Methods:

• In vitro biochemical assays.
• Protein-protein interaction studies.
• Analysis of macrolactone formation.

Main Results:

• PikAIII and PikAIV exhibit maximal efficiency in 12-membered macrocycle formation when interacting.
• The native protein-protein interaction facilitates the efficient release and cyclization of the hexaketide intermediate.
• Evidence suggests PikAIV adopts a specific conformation for optimal thioesterase activity.

Conclusions:

• The protein-protein interaction between PikAIII and PikAIV is essential for the efficient production of 10-deoxymethynolide.
• This interaction likely involves a conformational change in PikAIV to facilitate macrocyclization.
• Findings provide insights into modular PKS function and metabolic diversity generation.