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>. | |||
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<ref> PMID: 3889348 </ref>. It is released as this complex into the surrounding area, and Im3 is only released upon binding to a target cell. | 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<ref> PMID: 3889348 </ref>. It is released as this complex into the surrounding area, and Im3 is only released upon binding to a target cell. | ||
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{{STRUCTURE_2xfz | PDB=2xfz | SCENE= }} | {{STRUCTURE_2xfz | PDB=2xfz | SCENE= }} | ||
The C terminal domain of colicin E3 kills the cells that it penetrates by actively degrading the 16s rRNA subunit of the cell's 70S ribosome. This prevents the cell from producing any proteins once attacked, which will lead to the death of the cell. | The C terminal domain of colicin E3 kills the cells that it penetrates by actively degrading the 16s rRNA subunit of the cell's 70S ribosome. This prevents the cell from producing any proteins once attacked, which will lead to the death of the cell. This rRNA cleavage is specific ''in vivo'', but random when the rRNA domain is isolated ''in vitro''<ref> PMID: 368047 </ref>. The cleavage is unaffected by the presence of cellular ribonucleases<ref> PMID: 4567332 </ref>. The specific cleavage observed ''in vivo'' occurs within the ribosomal decoding A-site, in between A1493 and G1494, resulting in the complete halt of protein biosynthesis, leading to cell death<ref> PMID: 12423788 </ref>. | ||
==References== | ==References== | ||
<references/> | <references/> | ||