[Structural and functional organization of the colicin operon in the ColD-CA23 plasmid].

The organization of the genes involved in colicin D synthesis was studied. These are colicin, immunity and lysis genes. The nucleotide sequence of the immunity gene, its structural and regulatory regions were determined. This gene was shown to be located next to the colicin gene on the same strand and followed by the lysis gene. When colicin synthesis is induced with mitomycin C the immunity gene is transcribed from the general SOS-dependent promotor as a part of the colicin operon. However it has its own SOS-independent promotor in normal growth conditions. A high homology in amino acid sequences of Co1D lysis protein and that of Co1E1, Co1E2, Co1E3, Co1DF13, Co1A was revealed. A detailed scheme of Co1D-CA23 colicin operon structural organization is suggested.