Biosynthesis of streptothricin antibiotics. VII. Origin of streptolidine moiety in antibiotics from Streptomyces species.

Abstract

The effective production of streptothricin antibiotics by the addition of various amino acids (chemistry defined medium C) and the incorporation of 14C-labeled amino acids into streptothricin-C molecule (organic medium E) were studied with a strain of Streptomyces lavendulae OP-2. It was confirmed that proline, alanine, leucine, and arginine stimulated the production of antibiotics, and arginine and glycine promoted the mycelial growth. Of the amino acids tested, arginine was incorporated preferentially into streptothricin-C, but not tartaric acid or streptolidine itself. Approximately a one-half of radioactivity from arginine incorporated into the antibiotic was located in the streptolidine moiety. Furthermore, from the localization of 14C from arginine in the antibiotic molecule from four strains, a different pattern from that described above was observed. Localization of radioactivity in streptolidine moiety of racemomycin-A from S. lavendulae ISP-5069 was lower than that of β-lysine moiety, suggesting that biogenesis of streptolidine in streptothricins from S. lavendulae strains follows two pathways.