Duramycins B and C, two new lanthionine containing antibiotics, have been isolated from Streptoverticillium strain R2075 and Streptomyces griseoluteus (R2107). The known antibiotics duramycin and cinnamycin were reisolated from Streptoverticillium hachijoense (DSM401 14) and Streptomyces longisporoflavus (DSM40165). The structures of these latter two compoundsshould be revised by changing amino acid residue 3 to glutamine and 17 to asparagine, respectively.Cinnamycin therefore seems to be identical to Ro 09-0198. Leucopeptin has been shown to be identical to duramycin. Physico-chemical data of these compounds provide evidence for a similar structure for all duramycin antibiotics. All compoundsof this group inhibit humanphospholipase A2 at a concentration of 10~6 molar.Phospholipase A2 [EC 3.1.1.4] plays a major role in the release ofarachidonic acid from phospholipids in the cell membranes1*. Further oxidative metabolism of free arachidonic acid leads to prostaglandins and leukotrienes2).Several of these eicosanoids are potent mediators of diseases, such as inflammation and allergy3). Inhibition of the enzymic activity of phospholipase A2 may therefore be therapeutically beneficial.In our search for naturally occurring inhibitors of phospholipase A2 among secondary metabolites of microorganisms two newinhibitors from the actinomycetes strains R2075 and R2107 were identified which appeared to be closely related to the known peptide antibiotic duramycin. Using a different screening assay for compounds stimulating DNArepair, we found a strain producing duramycin as well as one producing cinnamycin (W. Marki and E. Rommele; unpublished results). In the present communication the taxonomy of these strains and the production, isolation, physico-chemical data and phospholipase inhibition of the newcompoundsduramycins B and C, as well as of duramycin and cinnamycin are described. Experimental results relating to the structural characterization are presented as well.
Materials and Methods
Microorganism
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