THE JOURNAL OF ANTIBIOTICS NEW CIRRAMYCIN-FAMILY ANTIBIOTICS F-l AND F-2 SELECTION OF PRODUCER MUTANTS, FERMENTATION, ISOLATION, STRUCTURAL ELUCIDATION AND ANTIBACTERIAL ACTIVITY

Two new 16-membered macrolides, cirramycins F-l and F-2, were isolated from the culture filtrate of a mutant strain B-1425 of Streptomyces drratus JTB-3. The antibiotics were also produced by bio-transformation of cirramycin AAusing a blocked mutant strain A-OO33. Structures of F-l and F-2 have been elucidated by spectral interpretation and analysis of acid degradation products. Both involved isomeric modification of a neutral sugar; F-l contained L-rhodinose, and F-2 L-amicetose. Based on spectral data, cirramycin F-l and antibiotic A6888C were found to be identical. Cirramycins F-l and F-2 are active against Gram-positive bacteria, but less active than cirramycin A^