ALL IN THE FAMILY - THE TOXIC ACTIVITY OF PORE-FORMING COLICINS

Colicins are unusual bacterial toxins because they are directed agains t close relatives of the producing strain. They kill their targets in one of three distinct ways; via a ribonuclease or deoxyribonuclease ac tivity or by forming pores in the target cell's membrane. This review deals with the steps involved in pore-forming colicin activity includi ng, initial synthesis of the toxin, toxin release, receptor binding, t ranslocation across the periplasm and pore formation in the cytoplasmi c membrane. Special reference is made to the role of colicin in vivo, the structural changes occurring during pore formation and the role of the immunity protein.