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A Cyclic Peptide Inhibitor of ApoC-II Peptide Fibril Formation: Mechanistic Insight from NMR and Molecular Dynamics Analysis
- Source :
-
Journal of Molecular Biology . Mar2012, Vol. 416 Issue 5, p642-655. 14p. - Publication Year :
- 2012
-
Abstract
- Abstract: The misfolding and aggregation of proteins to form amyloid fibrils is a characteristic feature of several common age-related diseases. Agents that directly inhibit formation of amyloid fibrils represent one approach to combating these diseases. We have investigated the potential of a cyclic peptide to inhibit fibril formation by fibrillogenic peptides from human apolipoprotein C-II (apoC-II). Cyc[60–70] was formed by disulfide cross-linking of cysteine residues added to the termini of the fibrillogenic peptide comprising apoC-II residues 60–70. This cyclic peptide did not self-associate into fibrils. However, substoichiometric concentrations of cyc[60–70] significantly delayed fibril formation by the fibrillogenic, linear peptides apoC-II[60–70] and apoC-II[56–76]. Reduction of the disulfide bond or scrambling the amino acid sequence within cyc[60–70] significantly impaired its inhibitory activity. The solution structure of cyc[60–70] was solved using NMR spectroscopy, revealing a well-defined structure comprising a hydrophilic face and a more hydrophobic face containing the Met60, Tyr63, Ile66 and Phe67 side chains. Molecular dynamics (MD) studies identified a flexible central region within cyc[60–70], while MD simulations of “scrambled” cyc[60–70] indicated an increased formation of intramolecular hydrogen bonds and a reduction in the overall flexibility of the peptide. Our structural studies suggest that the inhibitory activity of cyc[60–70] is mediated by an elongated structure with inherent flexibility and distinct hydrophobic and hydrophilic faces, enabling cyc[60–70] to interact transiently with fibrillogenic peptides and inhibit fibril assembly. These results suggest that cyclic peptides based on amyloidogenic core peptides could be useful as specific inhibitors of amyloid fibril formation. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 00222836
- Volume :
- 416
- Issue :
- 5
- Database :
- Academic Search Index
- Journal :
- Journal of Molecular Biology
- Publication Type :
- Academic Journal
- Accession number :
- 72369598
- Full Text :
- https://doi.org/10.1016/j.jmb.2011.12.059