STRUCTURE OF FUSCOPEPTINS, PHYTOTOXIC METABOLITES OF PSEUDOMONAS-FUSCOVAGINAE

The structure of the fuscopeptins, bioactive lipodepsipeptides produce d in culture by the gramineae pathogen Pseudomonas fuscovaginae, has b een determined, The combined use of FAB mass spectrometry, NMR spectro scopy and chemical and enzymatic procedures allowed one to define a pe ptide moiety corresponding to ZDhb-DPro-LLeu-DAla-DAla-DAla-DAla-DVal- DAla-DVal-DAla-DVal-ZDhb-DaThr-LAla-LDab-DDab-LPhe with the terminal carboxyl group closing a macrocyclic ring on the hydroxyl group of the allothreonine residue. The N-terminus is in turn acylated by 3-hydrox yoctanoate in fuscopeptin A and 3-hydroxydecanoate in fuscopeptin B. S ome preliminary data on the biological activity of fuscopeptins are al so reported.