(Science: pharmacology) a group of antibiotics naturally produced by the bacteria escherichia coli which kills other bacteria by a variety of methods (depending on the type), such as blocking protein synthesis and degrading dna.
Colicins are encoded by a group of naturally occurring E. Coli plasmids, like col e1.
Colicins e2 and E3 are ab toxins with DNAase and RNAase activity respectively. most other colicins are channel forming transmembrane peptides. Coded on plasmids which can be transferred at conjugation.