A Specialized Dehydrogenase Provides l-Phenyllactate for FR900359 Biosynthesis

Area of Science:

• Biochemistry
• Natural Product Biosynthesis
• Enzymology

Background:

• d-Phenyllactate (PLA) is a key component of the Gq protein inhibitor FR900359.
• Understanding PLA biosynthesis is critical for elucidating FR900359 production.

Purpose of the Study:

• To biochemically investigate the biosynthesis of d-PLA.
• To determine the role of the enzyme FrsC in PLA formation and incorporation into FR900359.
• To analyze the substrate specificity and evolutionary relationship of FrsC.

Main Methods:

• Enzyme kinetics and characterization of FrsC.
• Assaying the adenylation domain FrsE-A3.
• Feeding studies with a Chromobacterium vaccinii ΔfrsC mutant.
• Bioinformatic analysis of FrsC.

Main Results:

• FrsC catalyzes the formation of l-PLA from phenylpyruvate.
• l-PLA is preferentially activated and subsequently epimerized to d-PLA for incorporation.
• FrsC exhibits substrate specificity for larger aromatic compounds, related to malate dehydrogenases.

Conclusions:

• FrsC is essential for d-PLA biosynthesis and its integration into FR900359.
• Enzyme structural adaptations in FrsC facilitate specific substrate binding.
• This work provides insights into the natural product biosynthesis pathway.