The novel antibacterial peptide ceratotoxin A alters permeability of the inner and outer membrane of Escherichia coli K-12.

Ceratotoxins are antibacterial 3-kDa amphiphilic peptides isolated from the female reproductive apparatus of the medfly Ceratitis capitata. The antibacterial activity of a chemically synthesized ceratotoxin A (ctx A) has been investigated. Ctx A was mainly active against Gram-negative organisms, and it had a lytic effect on nongrowing Escherichia coli K-12. Data showed that ctx A alters both the outer and the inner membrane of E.coli K-12 cells.