Modulating the affinity and the selectivity of engineered calmodulin EF-Hand peptides for lanthanides.

A set of engineered peptides (33 amino acids long) corresponding to the helix-turn-helix (EF-Hand) motif of the metal-binding site I of the protein calmodulin from paramecium tetraurelia have been synthesized. A disulfide bridge has been introduced in the native sequence in order to stabilize a native-like conformation. The calcium-binding carboxylate residues in positions 20, 22, 24, and 31 were mutated into other amino acids and the influence of such mutations on the binding affinity of the peptides for calcium and lanthanides have been studied.

A case study of 2,2-dimethylthiazolidine as locked cis proline amide bond: synthesis, NMR and molecular modeling studies of a delta-conotoxin EVIA peptide analog.

The delta-conotoxin EVIA from the Conus ermineus venom, a recently characterized toxin, exhibits cis-trans isomerism of the Leu12-Pro13 bond associated with the triggering of its biological activity. In this paper we use the pseudoproline concept to target the presumed bioactive cis conformation. We report the design and the synthesis of loop 2 analogs from residue 8 to 18 containing either the cis-inducing Cys(PsiMe,MePro)13 unit or the natural proline residue.