Interactions between immobilized enzymes and supporting surfaces are complex and context-dependent and can significantly alter enzyme structure, stability and activity.

The screen of a fragment library identified hydrophobic fragments binding to drug resistant PfDHFR active site. Lead design using fragment-linking strategy yielded compounds with nM antimalarial activity, no cytotoxicity and drug-like properties.

An improved production and purification method for Alzheimer’s disease related methionine-modified amyloid-β 1–40 and 1–42 peptides is proposed, taking advantage of the formation of inclusion body in Escherichia coli. A Thioflavin-S assay was set-up to evaluate inclusion body formation during growth and optimize culture conditions for amyloid-β peptides production. A simple and fast purification protocol including first the isolation of the inclusion bodies and second, two cycles of high pH denaturation/ neutralization combined with an ultrafiltration step on 30-kDa cut-off membrane was established. Special attention was paid to purity monitoring based on a rational combination of UV spectrophotometry and SDS-PAGE analyses at the various stages of the process. It revealed that this chromatography-free protocol affords good yield of high quality peptides in term of purity. The resulting peptides were fully characterized and are appropriate models for highly reproducible in vitro aggregation studies.

The design of metal-binding sites in proteins that combine high affinity with high selectivity for the desired metal ion remains a challenging goal. Recently, a protein designed to display femtomolar affinity for ${\text{UO}}_2^{2+}$, dubbed “Super Uranyl-binding Protein” (SUP), was described, with potential applications for removing ${\text{UO}}_2^{2+}$ in water. Although it discriminated most metal ions present in seawater, the protein showed a surprisingly high affinity for Cu²⁺ ions. Here, we have investigated Cu²⁺ binding to SUP using a combination of electron paramagnetic resonance, fluorescence and circular dichroism spectroscopies. Our results provide evidence for two Cu²⁺ binding sites on SUP that are distinct from the ${\text{UO}}_2^{2+}$ binding site, but one of which interferes with ${\text{UO}}_2^{2+}$ binding. They further suggest that in solution the protein's secondary structure changes significantly in response to binding ${\text{UO}}_2^{2+}$; in contrast, the crystal structures of the apo- and holo-protein are almost superimposable. These results provide insights for further improving the selectivity of SUP for ${\text{UO}}_2^{2+}$, paving the way toward protein-based biomaterials for decontamination and/or recovery of uranium.