Effect of leucomycins and analogues on binding [14C ]erythromycin to Escherichia coli ribosomes.

We examined the effect of leucomycins, leucomycin derivatives, and other 16-membered macrolides (tylosin, niddamycin, spiramycin I, and spiramycin III) on [(14)C]erythromycin binding to ribosomes. Results of these studies enabled determination of the association and dissociation constants for the binding of each of these compounds to Escherichia coli ribosomes. In addition, the binding of the leucomycins and the leucomycin derivatives to ribosomes in general correlated with their antimicrobial activity.