Cloning of a Streptomyces gene for an O-methyltransferase involved in antibiotic biosynthesis.

The red pigmented antibiotic of Streptomyces coelicolor A3(2) is chemically very similar to the Serratia marcescens pigment, prodigiosin. We have demonstrated by co-synthesis experiments between non-producing mutants of both species that their biosynthetic pathways are similar, and have discovered identities between specific mutants of each organism. Molecular cloning techniques have been employed in order to isolate Streptomyces chromosomal DNA segments which "complement" a mutant defective in the penultimate step of the red biosynthetic pathway: an O-methyltransferase enzyme. In one case, the lesion appears to be repaired by integrative recombination into the chromosome; another case may represent expression from the autonomously replicating recombinant plasmid.