Identification of a Saccharopolyspora erythraea gene required for the final hydroxylation step in erythromycin biosynthesis.

In analyzing the region of the Saccharopolyspora erythraea chromosome responsible for the biosynthesis of the macrolide antibiotic erythromycin, we identified a gene, designated eryK, located about 50 kb downstream of the erythromycin resistance gene, ermE. eryK encodes a 44-kDa protein which, on the basis of comparative analysis, belongs to the P450 monooxygenase family. An S. erythraea strain disrupted in eryK no longer produced erythromycin A but accumulated the B and D forms of the antibiotic, indicating that eryK is responsible for the C-12 hydroxylation of the macrolactone ring, one of the last steps in erythromycin biosynthesis.