Metal ions play a critical role in human islet amyloid polypeptide (hIAPP) aggregation, which is believed to be closely associated with β-cell death in type II diabetes. In this work, the effect of Al3+ on the aggregation of hIAPP (11-28) was studied by several different experimental approaches. Atomic force microscopy measurements showed that Al3+ could remarkably inhibit hIAPP(11-28) fibrillogenesis, while Zn2+ had a slight promotion effect on peptide aggregation, which was also confirmed by Thioflavin T fluorescence observation. Furthermore, X-ray photoelectron spectroscopy measurement indicated that Al ions might form chemical bonds with neighboring atoms and destroy the secondary structures of the protein. Our studies could deepen the understanding of the role of metal ions in the aggregation of amyloid peptides.
Keywords: Thioflavin T fluorescence; X-ray photoelectron spectroscopy; atomic force microscopy; hIAPP peptides; metal ions.
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