View source for Colicin M

<StructureSection load='2xmx' size='350' side='right' caption='Structure of E. coli colicin M complex with glycerol and carbonate (PDB entry [[2xmx]])' scene=''>
'''Colicin M''' is a type of [[Colicin]], a bacteriocin made by ''E. coli'' which acts against other nearby ''E. coli'' to kill them by inhibiting synthesis of peptidoglycan - murein, preventing synthesis of the cell wall and ultimately leading to cell lysis. <scene name='Colicin_M/Colmsingle/1'>Monomer</scene> of Colicin M.


==Synthesis and release==

The operon for colicin M is encoded on a plasmid in the cytoplasm of the E. coli. This operon also encodes its [[Colicin Immunity Protein]], [[Cmi]], to protect the membrane of the cell from the activity of the cytotoxic domain, alongside a protein to aid the release of the colicin outside the cell. When produced, the immunity protein binds to and inhibits the enzymatic cytotoxic domain.

==Mechanism of uptake==

The receptor binding domain of the colicin binds to the outer membrane receptor FhuA on the target cell; it is 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.

==Killing Activities==

ColM shows enzymatic properties of degradation of lipid I and lipid II peptidoglycan intermediates. The cleavage occurs between the lipid moiety and the pyrophosphoryl groups. This then leads to the arrest of peptidoglycan polymerisation<ref> PMID: 16777846 </ref>, rather than the direct degradation of the peptidoglycan<ref> PMID: 7012126 </ref>.

==References==

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