Streptomyces griseoviridis 2464-S5 produces prodigiosin R1, a tripyrrole antibiotic, and roseophilin, a structurally related compound containing two pyrrole and one furan rings. A gene cluster for the biosynthesis of a prodigiosin was identified in S. griseoviridis. The cluster consisted of 24 open reading frames, including 21 genes (rphD-rphZ) homologous to prodigiosin biosynthesis genes in the red cluster in Streptomyces coelicolor A3(2). The expression of rphN in S. coelicolor lacking redN restored the production of prodigiosin.

Roseophilin is a unique metabolite containing two pyrrole and one furan ring and is structurally related to tripyrrole antibiotics, prodigiosins. Each homologous gene in the roseophilin producer Streptomyces griseoviridis was amplified by PCR using primers designed from the prodigiosin-biosynthesis genes redH, redM, and redW. A search for prodigiosins produced by S. griseoviridis resulted in the isolation of a new prodigiosin designated prodigiosin R1 (1). The molecular formula of 1 was established as C27H37N3O by high-resolution FABMS. The structure of 1 was elucidated by NMR spectroscopic analysis including COSY, HMQC, HMBC, and NOESY. Prodigiosin R1 (1) is a new member of the prodigiosin family possessing a cyclic alkyl side chain.