title: Modulating the affinity and the selectivity of engineered calmodulin EF-Hand peptides for lanthanides.
abstract: 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. It was shown that the binding affinity for terbium ions can be modulated with dissociation constants ranging from 40 nmolar to 40 mmolar. The study of the influence of the mutations on the terbium affinity showed that the residue in position 24 played a key role on the capability of the peptides to bind lanthanides and that the affinity could be enhanced by mutations on non-coordinating positions. Such peptides with high affinity for lanthanides may facilitate the development of new highly sensitive biosensors to monitor the metal pollution in the environment.
authors.affiliation: Département d'Ingénierie et d'Etudes des Protéines, Direction des Sciences du Vivant, Commissariat à l'Energie Atomique, Bat 152, 91191 Gif sur Yvette Cedex France. leclainche@dsvidf.cea.fr
authors.forename: Loïc Le
authors.initials: LL
authors.lastname: Clainche
authors.forename: Mélanie
authors.initials: M
authors.lastname: Figuet
authors.forename: Véronique
authors.initials: V
authors.lastname: Montjardet-Bas
authors.forename: Sébastien
authors.initials: S
authors.lastname: Blanchard
authors.forename: Claudio
authors.initials: C
authors.lastname: Vita
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D015374:Biosensing Techniques / Q000379:methods*; D002147:Calmodulin / Q000032:analysis* / Q000737:chemistry*; D007536:Isomerism; D028581:Lanthanoid Series Elements / Q000032:analysis* / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D011485:Protein Binding; D015202:Protein Engineering / Q000379:methods; D013050:Spectrometry, Fluorescence / Q000379:methods; D013329:Structure-Activity Relationship
chemical_list: D002147:Calmodulin; D028581:Lanthanoid Series Elements; D010455:Peptides