کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2185536 | 1095987 | 2010 | 16 صفحه PDF | دانلود رایگان |
The specific functional structure of natural proteins is determined by the way in which amino acids are sequentially connected in the polypeptide. The tight sequence/structure relationship governing protein folding does not seem to apply to amyloid fibril formation because many proteins without any sequence relationship have been shown to assemble into very similar β-sheet-enriched structures. Here, we have characterized the aggregation kinetics, seeding ability, morphology, conformation, stability, and toxicity of amyloid fibrils formed by a 20-residue domain of the islet amyloid polypeptide (IAPP), as well as of a backward and scrambled version of this peptide. The three IAPP peptides readily aggregate into ordered, β-sheet-enriched, amyloid-like fibrils. However, the mechanism of formation and the structural and functional properties of aggregates formed from these three peptides are different in such a way that they do not cross-seed each other despite sharing a common amino acid composition. The results confirm that, as for globular proteins, highly specific polypeptide sequential traits govern the assembly pathway, final fine structure, and cytotoxic properties of amyloid conformations.
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► Wild-type, scrambled, and backward versions of the IAPP 10–29 domain all form amyloids.
► The amyloidogenic pathways of the wild-type, scrambled, and backward versions of the IAPP 10–29 domain are different.
► The amyloid structures formed by the wild-type, scrambled, and backward versions of the IAPP 10–29 domain differ in stability, conformation, and cytotoxicity.
Journal: Journal of Molecular Biology - Volume 404, Issue 2, 26 November 2010, Pages 337–352