Effects of temperature on the activity of cloacin DF13 and cloacin DF13-immunity protein.

During the interaction of cloacin DF13 and sensitive cells the cloacin molecules display different functions which can be distinguished on the basis of their heat-sensitivity. Binding to cell envelope receptors, binding of immunity protein and in vitro inactivation of ribosomes are heat-stable functions in contrast with the entire killing action in vivo. Cloacin DF13-immunity protein appears to be a heat-stable inhibitor of the fibosome inactivation caused by cloacin DF13.