Functions encoded by pyrrolnitrin biosynthetic genes from Pseudomonas fluorescens

Area of Science:

• Microbiology
• Biochemistry
• Molecular Biology

Background:

• Pyrrolnitrin is a potent antifungal secondary metabolite derived from L-tryptophan.
• The biosynthetic genes (prnABCD) for pyrrolnitrin in Pseudomonas fluorescens were previously identified.

Purpose of the Study:

• To elucidate the specific function of each gene product within the prnABCD operon.
• To map the enzymatic steps in the pyrrolnitrin biosynthetic pathway.

Main Methods:

• Comparative analysis of protein presence in wild-type and mutant Pseudomonas fluorescens strains.
• Enzymatic assays to determine the catalytic activity of individual prn gene products.

Main Results:

• The prnA gene product catalyzes the initial chlorination of L-tryptophan.
• The prnB, prnC, and prnD gene products sequentially modify the intermediate to yield pyrrolnitrin.
• Gene organization within the operon directly reflects the order of biochemical reactions.

Conclusions:

• The prnABCD genes encode a complete biosynthetic pathway for pyrrolnitrin.
• The sequential action of prnA, prnB, prnC, and prnD enzymes defines the metabolic route from L-tryptophan to pyrrolnitrin.