Rhodopeptins, novel cyclic tetrapeptides with antifungal activities from Rhodococcus sp. II. Structure elucidation.

The structures of rhodopeptins, novel antifungal peptides, were determined on the basis of physico-chemical analyses of the intact molecules and their acid hydrolysates. The structures of rhodopeptins C1, C2, C3, C4 and B5 were determined to be cyclo (-Gly-L-Orn-L-Val-3-amino-10-methyldodecanoyl-), cyclo (-Gly-L-Orn-L-Ile-3-amino-10-methyldodecanoyl-), cyclo (-Gly-L-Orn-L-Val-3-amino-12-methyltridecanoyl-), cyclo (-Gly-L-Orn-L-Val-3-amino- 12-methyltetradecanoyl-) and cyclo (-Gly-L-Lys-L-Val-3-amino-13-methyltetradecanoyl-), respectively. They are novel cyclic tetrapeptides containing a lipophilic beta-amino acid.