Colicin E3: Difference between revisions
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==Synthesis and release== | ==Synthesis and release== | ||
The plasmid containing the colicin E3 gene is called ColE3-CA38, which is structurally homologous to that of the [[Colicin E2]] plasmid<ref> PMID: 7525540 </ref>. | The plasmid containing the colicin E3 gene is called ColE3-CA38, which is structurally homologous to that of the [[Colicin E2]] plasmid<ref> PMID: 7525540 </ref>. The expression of the operon is regulated by the lexA protein, as behind the promotor there are two inverted lexA binding regions<ref> PMID: 3889348 </ref>. The colicin, alongside its immunity protein, are not produced as a precursor protein requiring modification post-translationally. Instead they leave the colicinergic cell by a non-specific mechanism, whereby the permeability of the cell is increased<ref> PMID: 378936 </ref>. | ||
When colicin E3 is synthesised, it binds its 10kDa<ref> PMID: 7809274 </ref> [[Colicin Immunity Protein]], [[Im3]], to its cytotoxic domain in the cytoplasm. This prevents its RNase activity from occurring in the colicinogenic host, so it does not kill it | When colicin E3 is synthesised, it binds its 10kDa<ref> PMID: 7809274 </ref> [[Colicin Immunity Protein]], [[Im3]], to its cytotoxic domain in the cytoplasm. This prevents its RNase activity from occurring in the colicinogenic host, so it does not kill it. It is released as this complex into the surrounding area, and Im3 is only released upon binding to a target cell. In the normal state, Im3 is produced at a basal level to protect the cell from the colicin that it is producing, but in the SOS-induced state, initiated by lexA binding, a large amount is produced to protect the cell from externally produced ColE3<ref> PMID: 3889348 </ref>. | ||
==Mechanism of uptake== | ==Mechanism of uptake== | ||