| The role of aromatic side-chains in amyloid growth and membrane interaction of the islet amyloid polypeptide fragment LANFLVH. | |
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MedLine Citation:
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PMID: 20809197 Owner: NLM Status: In-Data-Review |
Abstract/OtherAbstract:
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Human islet amyloid polypeptide (hIAPP) is known to misfold and aggregate into amyloid deposits that may be found in pancreatic tissues of patients affected by type 2 diabetes. Recent studies have shown that the highly amyloidogenic peptide LANFLVH, corresponding the N-terminal 12-18 region of IAPP, does not induce membrane damage. Here we assess the role played by the aromatic residue Phe in driving both amyloid formation and membrane interaction of LANFLVH. To this aim, a set of variant heptapeptides in which the aromatic residue Phe has been substituted with a Leu and Ala is studied. Differential scanning calorimetry (DSC) and membrane-leakage experiments demonstrated that Phe substitution noticeably affects the peptide-induced changes in the thermotropic properties of the lipid bilayer but not its membrane damaging potential. Atomic force microscopy (AFM), ThT fluorescence and Congo red birefringence assays evidenced that the Phe residue is not required for fibrillogenesis, but it can influence the self-assembling kinetics. Molecular dynamics simulations have paralleled the outcome of the experimental trials also providing informative details about the structure of the different peptide assemblies. These results support a general theory suggesting that aromatic residues, although capable of affecting the self-assembly kinetics of small peptides and peptide-membrane interactions, are not essential either for amyloid formation or membrane leakage, and indicate that other factors such as β-sheet propensity, size and hydrophobicity of the side chain act synergistically to determine peptide properties. |
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Authors:
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Danilo Milardi; Michele F M Sciacca; Matteo Pappalardo; Domenico M Grasso; Carmelo La Rosa |
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Publication Detail:
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Type: Journal Article Date: 2010-09-01 |
Journal Detail:
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Title: European biophysics journal : EBJ Volume: 40 ISSN: 1432-1017 ISO Abbreviation: Eur. Biophys. J. Publication Date: 2011 Jan |
Date Detail:
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Created Date: 2010-12-14 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8409413 Medline TA: Eur Biophys J Country: Germany |
Other Details:
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Languages: eng Pagination: 1-12 Citation Subset: IM |
Affiliation:
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Istituto di Biostrutture e Bioimmagini, U.O.S. Catania, Consiglio Nazionale delle Ricerche, Viale Andrea Doria 6, 95125, Catania, Italy. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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