Mutational derivatives of microcin J25

An analog of bacteriocidal peptide microcin J25 (MccJ25) that (1) has an amino acid sequence that differs from that of MccJ25 by having at least one amino acid substitution;

• and (2) that inhibits bacterial cell growth with a potency at least equal to that of MccJ25, wherein the analog is selected from the group consisting of [Ser3] MccJ25 (SEQ ID NO:2), [Ile6] MccJ25 (SEQ ID NO:3), [Phe6] MccJ25 (SEQ ID NO:4), [Ala11] MccJ25 (SEQ ID NO:5), [Trp11] MccJ25 (SEQ ID NO:6), [Thr12] MccJ25 (SEQ ID NO:7), [Ser12] MccJ25 (SEQ ID NO:8), [Met12] MccJ25 (SEQ ID NO:9), [His12] MccJ25 (SEQ ID NO:10) [Leu13] MccJ25 (SEQ ID NO:11), [Ala13] MccJ25 (SEQ ID NO:12), [Asn13] MccJ25 (SEQ ID NO:13 [Arg13] MccJ25 (SEQ ID NO:14), [Pro13] MccJ25 (SEQ ID NO:15), [Thr13] MccJ25 (SEQ ID NO:16), [His13] MccJ25 (SEQ ID NO:17), [Val13] MccJ25 (SEQ ID NO:18), [Met13] MccJ25 (SEQ ID NO:19), [Phe13] MccJ25 (SEQ ID NO:20), [Trp13] MccJ25 (SEQ ID NO:21), [Ser14] MccJ25 (SEQ ID NO:22), [Thr14] MccJ25 (SEQ ID NO:23), [Phe15] MccJ25 (SEQ ID NO:24), [Gly15] MccJ25 (SEQ ID NO:25), [Leu15] MccJ25 (SEQ ID NO:26), [His15] MccJ25 (SEQ ID NO:27), [Asn15] MccJ25 (SEQ ID NO:28), [Ala15] MccJ25 (SEQ ID NO:29), [Ile15] MccJ25 (SEQ ID NO:30), [Trp15] MccJ25 (SEQ ID NO:31), [Met15] MccJ25 (SEQ ID NO:32), [Gln16] MccJ25 (SEQ ID NO:33), [Glu17] MccJ25 (SEQ ID NO:34), [Val17] MccJ25 (SEQ ID NO:35) and combinations thereof.