Novel recombinant hybrid colicin biosynthesis cluster encoded on pSSE3.Schematic representation of the colicin biosynthesis cluster on plasmid pSSE3 in comparison with colicin gene clusters of pColE7-K317 and pColE6-CT14. Grey vertical bars show homology in DNA sequences (with identity >80 %). The colicin structural gene (cea), immunity gene (cei) and lysis gene (cel) are annotated as shown. The three domains of the colicin structural gene are shown the key.