Dissonance Strikes a Chord in Stilbene Synthesizers

Area of Science:

• Biochemistry
• Structural Biology
• Microbial Metabolism

Background:

• Stilbenes are valuable natural products with diverse applications.
• Bacterial synthesis pathways for stilbenes are not fully understood.
• Previous studies have not identified the specific enzymes involved in bacterial stilbene production.

Purpose of the Study:

• To elucidate the biochemical mechanism of stilbene synthesis in bacteria.
• To identify and characterize the enzymes responsible for catalyzing stilbene formation.
• To determine the structural basis for the enzymatic activity in stilbene biosynthesis.

Main Methods:

• X-ray crystallography was employed to determine the structure of key enzymes.
• Biochemical assays were performed to analyze enzyme kinetics and substrate specificity.
• Mutagenesis studies were conducted to probe the function of the active site.

Main Results:

• A novel pathway for bacterial stilbene synthesis was discovered.
• The enzyme StlD was identified as a dialkyl-condensing enzyme utilizing a non-canonical β-ketosynthase active site.
• The enzyme StlC was found to catalyze the aromatization step, completing stilbene production.

Conclusions:

• The findings reveal a new enzymatic mechanism for stilbene biosynthesis in bacteria.
• The unique active site of StlD provides insights into enzyme evolution and substrate promiscuity.
• This study lays the groundwork for engineering microbial production of stilbenes.