Bacitracin A is the major analogue of the bacitracin complex of cyclic peptides, active against Gram-positive bacteria. Although first reported in 1945, the structure of the bacitracins was not fully elucidated until 1995. Bacitracins form a complex with C55-isoprenyl pyrophosphate and a metal ion to inhibit dephosphorylation and the transport of polysaccharides, peptidoglycans and lipopolysaccharides to the growing cell wall. Bacitracin is used clinically as a topical treatment for skin infections.