Zelkovamycin, a new cyclic peptide antibiotic from Streptomyces sp. K96-0670 II. Structure elucidation

The structure of antibiotic zelkovamycin was elucidated as a cyclic peptide comprising glycyl, 2-aminobutanoyl, 2-amino-2-butenoyl, N-methyl glycyl, a lanyl, 1,3-thiazoyl, 7-methoxytryptophanyl and 2-methyldehydrothreonyl resi dues. The sequence of the amino acids was established by spectroscopic stud ies including H-1-H-1 COSY,C-13-H-1 COSY, C-13-H-1 HMQC, C-13-H-1 HMBC, N-1 5-H-1 HMQC and N-15-H-1 HMBC NMR experiments.