Peptide antibiotic inhibiting growth of Gram-positive bacteria in the dimethylated form plantazolicin A. The desmethyl form plantazolicin B has no antibiotic activity. The mode of action appears to be disruption of cell walls and lysis of cells. Inhibits B.subtilis strain HB0042, B.megaterium strain 7A1 and B.anthracis (MIC=2-4 ug/ml). Weakly inhibits Gram-positive bacteria B.brevis strain ATCC 8246, B.subtilis strain 168, B.cereus strain ATCC 14579 and strain CU1065, B.licheniformis strain ATCC 9789, M.luteus, B.sphaericus, P.granivorans and S.pyogenes (MIC=128 ug/ml). Does not inhibit B.pumilus, P.polymyxa, Arthrobacter sp., S.aureus, vancomycin-resistant E.faecalis, L.monocytogenes, methicillin-resistant S.aureus or Gram-negative bacteria E.coli strain K12, K.terrigena, Pseudomonas sp. and E.carotovora. Maturation of thiazole and oxazole containing antibiotics involves the enzymatic condensation of a Cys, Ser or Thr with the alpha-carbonyl of the preceding amino acid to form a thioether or ether bond, then dehydration to form a double bond with the alpha-amino nitrogen. Thiazoline or oxazoline ring are dehydrogenated to form thiazole or oxazole rings. 2 forms exist: plantazolicin A and plantazolicin B. The structural difference between them is a dimethylation at Arg-28 in plantazolicin A. Plantazolicin A. Plantazolicin B. Plantazolicin A. Plantazolicin B.