Colicin
From Proteopedia
Introduction
Colicins are a type of bacteriocin - peptide and protein antibiotics released by bacteria to kill other bacteria of the same species. Bacteriocins are named after their species of origin; colicins are so-called because they are produced by E. Coli. Because of their narrow killing spectrum which focuses primarily on the species which has made the peptide, bacteriocins are important in microbial biodiversity and the stable co-existence of the bacterial populations.
Colicin peptides are plasmid-encoded. The peptide is released by the cell into the area surrounding it, and then parasitises proteins present in the host cell membrane to translocate across into the host cell. Many protein-protein interactions are involved in the cell entry, and the main system is involved in the grouping of colicins into two families: Group A colicins use the Tol system to enter the host cell, and Group B use the Ton system. Once inside the host cell, the cell killing follows 1st order kinetics - ie one molecule is sufficient to kill the cell.
The structure of all colicins, of which over 20 have been identified, follows a 3 domain design:
At the N terminus is the Translocation domain (T-)
The Receptor binding domain is at the centre of the peptide (R-)
The C terminus contains the Cytotoxic domain (C-).
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| 2k5x, 1 NMR models () | |||||||||
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| Gene: | imm, ceiE9 (Escherichia coli), col, cei (Escherichia coli) | ||||||||
| Related: | 1imq, 1fsj, 1emv | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
Proteopedia Page Contributors and Editors (what is this?)
Michal Harel, Gemma McGoldrick, Alexander Berchansky, Jaime Prilusky
