Dioxapyrrolomycin biosynthesis in Streptomyces fumanus

Area of Science:

• Microbial biosynthesis
• Natural product chemistry
• Organic chemistry

Background:

• Streptomyces fumanus produces a series of pyrrolomycins, with dioxapyrrolomycin as the primary compound.
• Pyrrolomycins are a class of natural products with potential biological activities.

Purpose of the Study:

• To elucidate the biosynthetic pathway of pyrrolomycins in Streptomyces fumanus.
• To identify the precursor molecules and metabolic intermediates involved in dioxapyrrolomycin production.

Main Methods:

• Feeding studies using isotopically labeled precursors: [methyl-13C]methionine, sodium nitrate (Na15NO3), and 15N-labeled L-proline.
• Analysis of labeled pyrrolomycins using techniques to detect enrichment in specific molecular positions.
• Investigating the conversion of minor pyrrolomycins (C, G, H) into dioxapyrrolomycin.

Main Results:

• Labeled acetate incorporation was observed exclusively in the phenyl ring of pyrrolomycins.
• 13C-labeled methionine contributed to the methoxy groups and the methylenedioxy bridge.
• 15N-labeling confirmed proline as a source for the pyrrole moiety and Na15NO3 for both nitrogen atoms.
• Minor pyrrolomycins (C, G, H) were shown to be direct precursors to dioxapyrrolomycin.

Conclusions:

• Streptomyces fumanus constructs the pyrrolomycin skeleton from L-proline and a polyketide precursor.
• A metabolic pathway exists where minor pyrrolomycins are intermediates in the biosynthesis of dioxapyrrolomycin.