Inhibition of heat-induced protein aggregation by zirconium phthalocyanines.

Specific proteins found in food sources tend to aggregate into fibrils under heat treatment; studying these aggregation processes and developing tools to control protein heat-induced aggregation is an active area of research. Phthalocyanine complexes are known to exhibit antiprionic and anti-fibrillogenic activity. Thus, the anti-fibrillogenic effect of a series of Zr phthalocyanines with different out-of-plane coordinated ligands, namely positively charged (PcZrLys ), negatively charged (PcZrCitr ), and group able to form disulfide bridges (PcZrS ), on the heat-induced aggregation of such proteins as BLG, insulin, and lysozyme was studied.

Synthesis and spectral characterization of the first fluorescein-tagged iron(ii) clathrochelates, their supramolecular interactions with globular proteins, and cellular uptake.

A fluorescein-tagged iron(ii) cage complex was obtained in a moderate total yield using a two-step synthetic procedure starting from its propargylamine-containing clathrochelate precursor. An 11-fold decrease in fluorescence quantum yield is observed in passing from the given fluorescein-based dye to its clathrochelate derivative. An excitation energy transfer from the terminal fluorescent group of the macrobicyclic molecule to its quasiaromatic highly π-conjugated clathrochelate framework can explain this effect.

Modification of insulin amyloid aggregation by Zr phthalocyanines functionalized with dehydroacetic acid derivatives.

Amyloid fibrils are widely studied both as target in conformational disorders and as basis for the development of protein-based functional materials. The three Zr phthalocyanines bearing dehydroacetic acid residue (PcZr(L1)2) and its condensed derivatives (PcZr(L2)2 and PcZr(L3)2) as out-of-plane ligands were synthesized and their influence on insulin fibril formation was studied by amyloid-sensitive fluorescent dye based assay, scanning electron microscopy, fluorescent and absorption spectroscopies. The presence of Zr phthalocyanines was shown to modify the fibril formation.

Sensing of Proteins by ICD Response of Iron(II) Clathrochelates Functionalized by Carboxyalkylsulfide Groups.

Recognition of elements of protein tertiary structure is crucial for biotechnological and biomedical tasks; this makes the development of optical sensors for certain protein surface elements important. Herein, we demonstrated the ability of iron(II) clathrochelates (-) functionalized with mono-, di- and hexa-carboxyalkylsulfide to induce selective circular dichroism (CD) response upon binding to globular proteins. Thus, inherently CD-silent clathrochelates revealed selective inducing of CD spectra when binding to human serum albumin (HSA) (, ), beta-lactoglobuline () and bovine serum albumin (BSA) ().