Metal-binding proteins are macromolecules capable of finely tuning the properties of metal-binding sites, their affinity and selectivity for the metal of interest. The aim of this thesis is to optimize protein binding sites for lanthanides (Ln(III)) and americium (Am(III)) and, notably sites that are selective within the Ln(III) series or between Am(III) and Ln(III).
It will build upon recent work by the BIAM/IPM and DES/LILA teams, which demonstrated the possibility of generating affine binding sites for Ln(III) and Am(III), with LogK = 9–12, by introducing a lanthanide-binding peptide (LBT, Nitz et al. 2004) in place of the calcium-binding site on a truncated form of calmodulin (Berthomieu et al. 2026; Daronnat et al. in preparation).
The aim of this thesis is to explore the effect of modifications to the amino acid sequence involved in lanthanide binding at sites 1 and 2 of the N-terminal domain of calmodulin on the protein’s affinity and its intra-lanthanide or Ln(III)-Am(III) selectivity, as well as their impact on potential cooperative binding between the two sites. Smaller proteins/peptides will also be studied to optimize capture capabilities and enable the acquisition of structural data via solution NMR.
This thesis will involve protein engineering (focused directed evolution, post-translational modifications) guided by AI and molecular dynamics approaches, as well as the analysis of protein–f-element interaction properties using complementary spectroscopy and analytical chemistry techniques (notably UV-Vis, Fluorescence, TRLIFS, FTIR, NMR, ITC and protein crystallography). It will make it possible to assess the feasibility of implementing bio-based approaches for the selective extraction of f-elements.