The structures of the amphiphilic peptide antibiotics herbicolin A and B were determined by application of physical methods, chemical degradation, and partial syntheses. Herbicolin B is a lipodepsinonapeptide with the sequence DH-Abu-L-Thr-D-aThr-D-Leu-Gly-D-Gln-Gly-N-Me-L-aThr-L-Arg (DH-Abu = 2,3-dehydro-a-aminobutyric acid). The C-terminal Arg residue forms a lactone ring with the hydroxy group of L-Thr, while the N-terminus is acylated by an (R)-3-hydroxytetradecanoic acid residue. The main component herbicolin A differs from herbicolin B in an additional D-glucose moiety linked in an l-u-glycosidic bond to the 3-hydroxytetradecanoic acid residue. Thus herbicolin A constitutes the first glycolipodepsinonapeptide antibiotic known so far. Strukturaufklarung der Peptidantibiotika Herbicolin A und B Die Struktur der amphiphilen Peptidantibiotika Herbicolin A und B konnte mit physikalischen Methoden sowie durch chemischen Abbau und Partialsynthesen identificrt werden. Herbicolin B ist ein Lipodepsipeptid der Sequenz DH-Abu-L-Thr-D-aThr-D-Leu-Gly-D-Gln-Cly-N-Me-L-aThr-L-Arg (DH-Abu = 2,3-Dehydro-u-aminobuttersaure), dessen C-terminaler Argininrest mit der Hydroxygruppe von L-Thr lactonisiert und dessen N-Terminus durch (R)-3-Hydroxytetradecansaure acyliert ist. In der Hauptkomponente Herbicolin A ist im Unterschied zu Herbicolin B zusatzlich ein Molekul D-Glucose l-cc-glycosidisch mit der 3-Hydroxytetradecansaure verknupft. Somit ist Herbicolin A das erste bekannte Glycolipodepsinonapeptid-Antibiotikum.
Herbicolins A and B were isolated from a bacterial strain A 11 1, identical with Erwinia herbicola, in a screening program for antifungal agents. Both antibiotics are highly active against yeasts and filamentous fungi but not active against bacteria 'a2).
The herbicolins show minimal inhibition concentrations (MIC) of 0.2-0.6 pg/ml in serial dilution tests against Trichophyton rubrum, Epidermophylon ,floccosum, and Microsporum canis3'. Herbicolin A inhibits the growth of the sterol-requiring Mycoplasma, Ureaplasma,