Enniatins synthetic analogues

An extensive range of synthetic analogues of valinomycin and the enniatins has been prepared and investigated these studies have been fully described in ai monograph.532 Synthetic peptides have also been prepared and their complexing properties investigated for example [L-Val-D-Pro-D-Val-L-Pro]3 reacts with potassium picrate to give an isolable 1 1 complex which is expected to have a structure similar to that of the K+ complex of (137).557 More detailed studies have been made on the complexation properties of the small synthetic peptides [L-Pro-Gly]3 and [L-Pro-Gly]4. 

Polylactones (for an example, see Fig. 14.4) are synthetic analogues of naturally occurring ionophores such as enniatin (species that transport ions across biological membranes). Molecular mechanics calculations have been used to predict the stability and selectivity with respect to Li+, Na+, and K+ of a series of new polylactones12661. Metal-ligand interactions were again modeled using a combination of van der Waals and electrostatic terms. 

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