NOVEL BIOACTIVE LIPODEPSIPEPTIDES FROM PSEUDOMONAS-SYRINGAE - THE PSEUDOMYCINS

The covalent structure and most of the stereochemistry of the pseudomy cins, bioactive metabolites of a transposon-generated mutant of a Pseu domonas syringae wild-type strain proposed for the biological control of Dutch elm disease, have been determined. While two pseudomycins are identical to the known syringopeptins 25-A and 25-B, pseudomycins A, B, C, C' are new lipodepsinonapeptides. For all of these the peptide m oiety corresponds to p-L-Lys-L-Dab-L-aThr-Z-Dhb-L-Asp(3-OH)-L-Thr(4-Cl ) with the terminal carboxyl group closing a macrocyclic ring on the O H group of the N-terminal Ser. This is in turn N-acylated by 3,4-dihyd roxytetradecanoate in pseudomycin A, by 3-hydroxytetradecanoate in pse udomycin B, by 3,4-dihydroxyhexadecanoate in pseudomycin C, and by 3-h ydroxyhexadecanoate in pseudomycin C'. Some preliminary data on the bi ological activity of pseudomycin A are reported.