β-Lactone Synthetase Found in the Olefin Biosynthesis Pathway

Area of Science:

• Biochemistry
• Natural Product Biosynthesis
• Enzymology

Background:

• Microbial biosynthesis of long-chain olefinic hydrocarbons involves specific enzymes.
• Natural products often feature complex cyclic structures like beta-lactones.
• The enzymatic pathways connecting hydrocarbon and complex natural product biosynthesis were unclear.

Purpose of the Study:

• To identify and characterize the first beta-lactone synthetase enzyme.
• To investigate the enzymatic mechanism for beta-lactone ring formation.
• To explore the evolutionary and biosynthetic links between hydrocarbon and natural product pathways.

Main Methods:

• Enzyme purification and characterization of OleC.
• Substrate specificity studies using syn- and anti-beta-hydroxy acids.
• Bioinformatic analysis of homologous enzymes in natural product gene clusters.

Main Results:

• The enzyme OleC was identified as a beta-lactone synthetase.
• OleC catalyzes the formation of cis-beta-lactones from syn-beta-hydroxy acids and trans-beta-lactones from anti-beta-hydroxy acids.
• Homologous enzymes are present in gene clusters for diverse beta-lactone natural products, indicating a conserved biosynthetic mechanism.

Conclusions:

• The discovery of OleC reveals a novel enzymatic pathway for beta-lactone biosynthesis.
• This finding establishes an unexpected connection between olefinic hydrocarbon and natural product biosynthesis.
• A common enzymatic mechanism for beta-lactone formation is suggested across different microbial pathways.