Fine-tuning non-covalent interactions between hybrid metal-oxo clusters and proteins.

Interactions between the protein Hen Egg White Lysozyme (HEWL) and three different hybrid Anderson-Evans polyoxometalate clusters - AE-NH2 (δ-[MnMoO{(OCH)CNH}]), AE-CH3 (δ-[MnMoO{(OCH)CCH}]) and AE-Biot (δ-[MnMoO{(OCH)CNHCOCHNOS}]) - were studied tryptophan fluorescence spectroscopy and single crystal X-ray diffraction. Quenching of tryptophan fluorescence was observed in the presence of all three hybrid polyoxometalate clusters (HPOMs), but the extent of quenching and the binding affinity were greatly dependent on the nature of the organic groups attached to the cluster. Control experiments further revealed the synergistic effect of the anionic polyoxometalate core and organic ligands towards enhanced protein interactions.

Revealing the three-dimensional murine brain microstructure by contrast-enhanced computed tomography.

To improve our understanding of the brain microstructure, high-resolution 3D imaging is used to complement classical 2D histological assessment techniques. X-ray computed tomography allows high-resolution 3D imaging, but requires methods for enhancing contrast of soft tissues. Applying contrast-enhancing staining agents (CESAs) ameliorates the X-ray attenuating properties of soft tissue constituents and is referred to as contrast-enhanced computed tomography (CECT).

Crystal structures of Scone: pseudosymmetric folding of a symmetric designer protein.

Recent years have seen an increase in the development of computational proteins, including symmetric ones. A ninefold-symmetric β-propeller protein named Cake has recently been developed. Here, attempts were made to further engineer this protein into a threefold-symmetric nine-bladed propeller using computational design.

Hybrid assemblies of a symmetric designer protein and polyoxometalates with matching symmetry.

Novel bioinorganic hybrid materials based on proteins and inorganic clusters have enormous potential for the development of hybrid catalysts that synergistically combine properties of both materials. Here we report the creation of hybrid assemblies between a computationally designed symmetrical protein Pizza6-S and different polyoxometalates with matching symmetry: the tellurotungstic Anderson-Evans (Na6[TeW6O24]·22H2O) (TEW); Keggin (H4[SiW12O40]·6H2O) (STA); and 1 : 2 CeIII-substituted Keggin (K11[CeIII[PW11O39]2]·20H2O) (Ce-K). This results in the formation of complexes with clearly defined stoichiometries in solution.

Redox Activity of Ce(IV)-Substituted Polyoxometalates toward Amino Acids and Peptides.

Redox reactions between polyoxometalates (POMs) and biologically relevant molecules have been virtually unexplored but are important, considering the growing interest in the biological applications of POMs. In this work we give a detailed account on the redox behavior of Ce-substituted polyoxometalates (Ce-POMs) toward a range of amino acids and peptides. Ce-POMs have been shown to act as artificial proteases that promote the selective hydrolysis of peptide bonds.