ABSTRACT
This chapter discusses chemistry of 11 polyether antibiotics, and in the cases where data has been published the biological consequences of their chemical transformations will also be presented. The distinguishing characteristic of the polyether antibiotics compared to other ionophores is the presence of a carboxylic acid moiety. By virtue of this functional group they are able to replace the water mantle which normally surrounds alkaline or alkaline earth cations and then transport them as neutral hydrophobic complexes across the membrane. By adopting a conformation in which all the oxygens of the molecule are concentrated at the center around the cation and all the lipophilic branched alkyl groups are spread over the outer surface of the complex, the polyether antibiotics catalyze an electroneutral cation-proton exchange across the membrane, moving as undissociated acids in one direction and neutral complexes in the other.
