Institute of Molecular Biology and Genetics, NASU, Kyiv, Ukraine.
Institute of Low Temperature and Structure Research, PAS, Wroclaw, Poland.
PLoS One. 2021 Jan 7;16(1):e0243904. doi: 10.1371/journal.pone.0243904. eCollection 2021.
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. The morphology of fibrils formed in the presence of the Zr phthalocyanines differs from that of free insulin and depends on the structure of out-of-plane ligands. It is shown that free insulin mostly forms fibril clusters with the length of about 0.3-2.1 μm. The presence of Zr phthalocyanines leads to the formation of individual 0.4-2.8 μm-long fibrils with a reduced tendency to lateral aggregation and cluster formation (PcZr(L1)2), shorter 0.2-1.5 μm-long fibrils with the tendency to lateral aggregation without clusters (PcZr(L2)2), and fibril-like 0.2-1.0 μm-long structures (PcZr(L3)2). The strongest influence on fibrils morphology made by PcZr(L3)2 could be explained by the additional stacking of phenyl moiety of the ligand with aromatic amino acids in protein. The evidences of binding of studied Zr phthalocyanines to mature fibrils were shown by absorption spectroscopy (for PcZr(L1)2 and PcZr(L2)2) and fluorescent spectroscopy (for PcZr(L3)2). These complexes could be potentially used as external tools allowing the development of functional materials on protein fibrils basis.
淀粉样纤维被广泛研究，既是构象紊乱的靶点，也是基于蛋白质的功能材料的基础。合成了三种带有脱氢乙酸残基的Zr 酞菁（PcZr（L1）2）及其缩合衍生物（PcZr（L2）2 和 PcZr（L3）2）作为平面外配体，并通过基于淀粉样敏感荧光染料的测定、扫描电子显微镜、荧光和吸收光谱研究了它们对胰岛素纤维形成的影响。结果表明，Zr 酞菁的存在可以改变纤维的形成。在 Zr 酞菁存在下形成的纤维的形态与游离胰岛素的形态不同，并且取决于平面外配体的结构。结果表明，游离胰岛素主要形成长度约为 0.3-2.1μm 的纤维簇。Zr 酞菁的存在导致形成具有降低的侧向聚集和簇形成倾向的单个 0.4-2.8μm 长的纤维（PcZr（L1）2），具有侧向聚集而没有簇的较短的 0.2-1.5μm 长的纤维（PcZr（L2）2）和纤维状的 0.2-1.0μm 长的结构（PcZr（L3）2）。对纤维形态的最强影响可以通过配体的苯基部分与蛋白质中的芳族氨基酸的额外堆积来解释。通过吸收光谱（对于 PcZr（L1）2 和 PcZr（L2）2）和荧光光谱（对于 PcZr（L3）2）证明了研究的 Zr 酞菁与成熟纤维的结合。这些配合物可以作为外部工具，潜在地用于基于蛋白质纤维的功能材料的开发。
