Research will be directed to the following problems: (1) Mechanism by which colicins K and El abolish the membrane potential of sensitive cells. Colicin will embedded into membranes and the channel properties of colicin molecules verified in a variety of ways, including bacterial systems as well as artificial membranes. (2) The transport of protons across membranes by gamma-helices in membrane proteins will be pursued in an effort to verify a recently proposed hypothesis. (3) The nature of a protein inhibitor induced by colicins El and K in sensitive cells will be studied by a variety of chemical methods, and the mode of action of the inhibitor will be explored.