Peptide conformation and supramolecular organization in amylin fibrils: Constraints from solid-state NMR

Sorin Luca, Wai Ming Yau, Richard Leapman, Robert Tycko

Research output: Contribution to journalArticle

420 Scopus citations

Abstract

The 37-residue amylin peptide, also known as islet amyloid polypeptide, forms fibrils that are the main peptide or protein component of amyloid that develops in the pancreas of type 2 diabetes patients. Amylin also readily forms amyloid fibrils in vitro that are highly polymorphic under typical experimental conditions. We describe a protocol for the preparation of synthetic amylin fibrils that exhibit a single predominant morphology, which we call a striated ribbon, in electron microscopy and atomic force microscopy images. Solid-state nuclear magnetic resonance (NMR) measurements on a series of isotopically labeled samples indicate a single molecular structure within the striated ribbons. We use scanning transmission electron microscopy and several types of one- and two-dimensional solid-state NMR techniques to obtain constraints on the peptide conformation and supramolecular structure in these amylin fibrils and to derive molecular structural models that are consistent with the experimental data. The basic structural unit in amylin striated ribbons, which we call the protofilament, contains four layers of parallel β-sheets, formed by two symmetric layers of amylin molecules. The molecular structure of amylin protofilaments in striated ribbons closely resembles the protofilament in amyloid fibrils with a similar morphology formed by the 40-residue β-amyloid peptide that is associated with Alzheimer's disease.

Original languageEnglish (US)
Pages (from-to)13505-13522
Number of pages18
JournalBiochemistry
Volume46
Issue number47
DOIs
StatePublished - Nov 27 2007
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

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