Immunity protein is not required for the bactericidal activity of colicin E3.
Plasmid pLAX3, carrying the colicin E3 gene, was used to direct the in vitro synthesis of a colicin E3* molecule totally devoid of its immunity protein. We established that this molecule is able to kill sensitive Escherichia coli cells in the total absence of immunity protein. Therefore, all of the information required for colicin E3 action is located on the colicin polypeptide itself. Furthermore, our studies indicated that immunity protein protects the C-terminal enzymatic part of native colicin E3 protein against proteolytic degradation before or during its translocation across the cell envelope. These results are discussed in relation to the mode of entry of colicin E3 into bacterial cells.
Escuyer
V
V
Unité des Antigènes Bactériens, Institut Pasteur, Paris, France.
Perrin
D
D
Mock
M
M
D001426:Bacterial Proteins / Q000502:physiology*; D003001:Cloning, Molecular; D003087:Colicins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins; D010447:Peptide Hydrolases / Q000378:metabolism; D010957:Plasmids; D013997:Time Factors
D001426:Bacterial Proteins; D003087:Colicins; D029968:Escherichia coli Proteins; C488855:ceiC protein, E coli; C007104:colicin immunity proteins; D010447:Peptide Hydrolases