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Updated: Jun 23, 2026

Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain
Published on: August 28, 2012
Conformational polymorphism and cellular toxicity of IAPP and beta AP domains
Maneesha E Andrews1, N Mohammed Inayathullah, Rajadas Jayakumar
1Bio Organic Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India.
Abstract:
The principal component of the amyloid deposits in Alzheimer's disease is the beta-amyloid polypeptide, while in type II diabetes the deposits consist primarily of Islet amyloid polypeptide. These amyloid forming polypeptides consist of highly polymorphic domains, which take different conformations including random coil, helical and beta strand depending upon the microenvironment. We have studied major fibril-forming components of IAPP and beta AP and demonstrated that conformational polymorphism of these peptides in different microenvironments correlate with cellular toxicity and proteasomal inhibitory activity. On treating with trifluoroethanol (TFE) the peptide fragments undergo structural transition from a random coil to a helical conformation. Even though these domains share the same gross amyloid structural characteristic, their proteasomal activities differ. We found that even the tetrapeptides have significant proteasomal inhibitory activity indicating that the amyloid formation is involved in the enhanced life of the smaller aggregates of full-length and fragment peptides, which could explain the toxicity of these sequences.
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