The disclosure relates to the identification, cloning, and expression of a genetic locus within a Listeria monocytogenes genome that encodes a phage tail-like bacteriocin (PTLB), termed a monocin. Also provided are non-natural monocins, which have been engineered to have altered bactericidal specificity. Nucleic acid molecules encoding natural or non-natural monocins, vector constructs containing such nucleic acids operably linked to a heterologous promoter, producer cells containing such vectors, the encoded monocins, as well as methods of making and using such monocins are described.
