Two-dimensional IR spectroscopy and isotope labeling defines the pathway of amyloid formation with residue-specific resolution

Sang-Hee Shim, Ruchi Gupta, Yun L. Ling, David B. Strasfeld, Daniel P. Raleigh, Martin T. Zanni

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209 Citations (Scopus)

Abstract

There is considerable interest in uncovering the pathway of amyloid formation because the toxic properties of amyloid likely stems from prefibril intermediates and not the fully formed fibrils. Using a recently invented method of collecting 2-dimensional infrared spectra and site-specific isotope labeling, we have measured the development of secondary structures for 6 residues during the aggregation process of the 37-residue polypeptide associated with type 2 diabetes, the human islet amyloid polypeptide (hIAPP). By monitoring the kinetics at 6 different labeled sites, we find that the peptides initially develop well-ordered structure in the region of the chain that is close to the ordered loop of the fibrils, followed by formation of the 2 parallel β-sheets with the N-terminal β-sheet likely forming before the C-terminal sheet. This experimental approach provides a detailed view of the aggregation pathway of hIAPP fibril formation as well as a general methodology for studying other amyloid forming proteins without the use of structure-perturbing labels.

Original languageEnglish
Pages (from-to)6614-6619
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number16
DOIs
Publication statusPublished - 2009 Apr 21
Externally publishedYes

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Keywords

  • Aggregation
  • Amylin
  • Fibers
  • Human islet amyloid polypeptide
  • Nucleation

ASJC Scopus subject areas

  • General

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