The structure of plumbemycin A and B, new antimetabolites from Streptomyces plumbeus, which are antagonist of L-threonine, were assigned to be L-alanyl-L-aspartyl-D-2-amino-5-phosphono-3-cis-pentenoic acid and L-alanyl-L-asparaginyl-D-2-amino-5-phosphono-3-cis-pentenoic acid, respectively.
