Colicin E1 (microcin) immunity protein (IPR003061)

Short name: Microcin

Overlapping homologous superfamilies


Family relationships



The structural and functional relationships among independently cloned segments of the plasmid ColE1 region that regulates and codes for colicin E1 (cea), immunity (imm) and the mitomycin C-induced lethality function (lys) have been analysed [PMID: 3936034]. A model for the structure and expression of the colicin E1 operon has been proposed in which the cea and lys genes are expressed from a single inducible promoter that is controlled by the lexA repressor in response to the SOS system of Escherichia coli [PMID: 3936034]. The imm gene lies between the cea and lys genes and is expressed by transcription in the opposite direction from a promoter located within the lys gene [PMID: 3936034]. This arrangement indicates that the transcriptional units for all three genes overlap. It is proposed that the formation of anti-sense RNA may be an important element in the coordinate regulation of gene expression in this system [PMID: 3936034].

Hydropathy analysis of the imm gene products suggests that they have hydrophobic domains characteristic of membrane-associated proteins [PMID: 3936034]. The microcin E1 immunity protein is able to protect a cell that harbours the plasmid ColE1 encoding colicin E1 against colicin E1; it is thus essential both for autonomous replication and colicin E1 immunity [PMID: 384144].

GO terms

Biological Process

GO:0030153 bacteriocin immunity

Molecular Function

GO:0015643 toxic substance binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.