Cloning and characterization of bagB and bagC, two co-transcribed genes involved in bagremycin biosynthesis in Streptomyces sp. Tü 4128

Bagremycin A and B, produced by Streptomyces sp. Tü 4128, are two antibiotics active against Gram-positive bacteria and fungi. To elucidate the biosynthetic pathway of bagremycins, two genes named bagB and bagC, were cloned and characterized from a bagremycin-producing strain. The deduced protein products of bagB and bagC show high sequence identity with aldolase and 3-dehydroquinate synthase, respectively. The bagC gene is located immediately downstream of the bagB gene and subsequent reverse transcription and polymerase chain reaction analysis revealed that bagB is co-transcribed with bagC. Inactivation of either bagB or bagC resulted in the complete abolishment of bagremycin production in fermented cultures, which suggests that these two genes are involved in the biosynthesis of bagremycins. The results from this study will allow acquisition of the entire biosynthetic cluster for bagremycins and further our understanding of the biosynthetic pathway and mechanism of action of bagremycin.