Title
Anti-fibrillogenic and fibril destabilizing effects of metal ions on cystatin fibrils
Author
Waseem Feeroze Bhat, Sheraz Ahmad Bhat, Imtiyaz Ahmad Bhat, Aamir Sohail, Aaliya Shah, Bilqees Bano
Year
2017
Journal
Process Biochemistry
Abstract
Metals such as Cu2+, Fe3+, and Zn2+ are major contributors to the biology of a brain in stages of health, aging, and disease because of their unique effects on both protein structures (misfolding) and oxidative stress. The relationship between metal ions and neurodegenerative diseases is very complicated. Our study highlights how metal ions influence amyloid formation at low pH and on preformed amyloid fibrils. By using thioflavin T assay, ANS fluorescence, Congo red assay, circular dichroism, and microscopy to elucidate the effects of Cu2+, Fe3+, and Zn2+ on goat brain cystatin (GBC) aggregation at low pH. Results showed that Cu2+ and Fe3+ inhibit fibril formation of GBC by promoting amorphous aggregates. However, Zn2+ exclusively promotes fibril formation at low pH, leading to the formation of more ordered aggregates. Furthermore, the combined results of these complementary methods also suggested that Cu2+ and Fe3+ destabilize the β-sheet secondary structure of preformed amyloid fibrils of GBC.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Chemical stability, Ligand binding, Aggregation, Biochemistry