Pyralomicins, Novel Antibiotics from Microtetraspora spiral

III. Biosynthesis of Pyralomicin 1a

Abstract

The biosynthesis of pyralomicin la (1) was studied by feeding of ¹³C and ¹⁵N labeled compounds to the culture of Microtetraspora spiralis MI178-34F18. The result indicated that the benzopyranopyrrole unit of 1 was derived from two units of acetate, one unit of propionate and one unit of proline, and that the cyclitol unit of 1 was derived from glucose metabolites. And 4'-O-CH₃ was derived from the S-CH₃ group of methionine.