The gram-negative bacterial membrane is of extreme medical importance. Two of its major components are lipopolysaccharides (LPS's) and integral membrane proteins. Porins are beta-barrel, pore-forming, membrane proteins found in the outer membrane of gram-negative bacteria. We have produced and examined Porin-lipid monolayers at the air/liquid interface and used this to examine bacterial toxin-membrane interactions. The porin OmpF is the receptor for the antibacterial toxin colicin N and enables the toxin to translocate across the bacterial outer membrane in order to kill E coli cells. Here, we propose to examine the interaction of engineered colicins with OmpF-LipidA (the membrane bound portion of LPS) monolayers. Aiming to determine the mechanism of Colicin-bacterial membrane interactions as well as similarities and differences between the activities of differing colicin types.