Colicin V
Colicin V is a type of Colicin, a bacteriocin made by E. coli which acts against other nearby E. coli to kill them by forming a pore in the membrane, leading to depolarisation of the membrane which kills the cell.
Synthesis and releaseSynthesis and release
The operon for colicin V is encoded on a plasmid in the cytoplasm of the E. coli. This operon also encodes its Colicin Immunity Protein, Cvi, to protect the membrane of the cell from the pore forming activities of the colicin, alongside a protein to aid the release of the colicin outside the cell.
Once produced, the immunity protein inserts into the membrane to prevent pore formation and membrane depolarisation.
Mechanism of uptakeMechanism of uptake
The receptor binding domain of the colicin binds to an outer membrane protein, probably Cir[1]; a constitutively expressed protein parasitised by the colicin. The translocation domain then recruits proteins from the Ton system to translocate the protein across the membrane and into the cytoplasm.