Identification of a gene required for the terminal step in erythromycin A biosynthesis in Saccharopolyspora erythraea (Streptomyces erythreus).

We have identified a transcription unit in the ermE region of the chromosome of the erythromycin (Er)-producing bacterium Saccharopolyspora erythraea (Streptomyces erythreus) that is briefly switched on at about the time that macrolide production commences. Disruption of the transcription unit, herein designated eryG, by insertion of an integrational plasmid vector, caused a block at the terminal step in the biosynthesis of erythromycin, the conversion of erythromycin C to A by O-methylation.