Title:
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Self-assembly of Fmoc-tetrapeptides based on the RGDS cell adhesion motif
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Author:
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Alemán Llansó, Carlos; Castelletto, V.; Moulton, C.M.; Cheng, G.; Hamley, I. W.; Hicks, Mathew R.; Rodger, Alison; López Pérez, David Orencio; Revilla López, Guillermo
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Other authors:
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Universitat Politècnica de Catalunya. Departament d'Enginyeria Química; Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear; Universitat Politècnica de Catalunya. GRPFM - Grup de Recerca en Propietats Físiques dels Materials; Universitat Politècnica de Catalunya. IMEM - Innovació, Modelització i Enginyeria en (BIO) Materials |
Abstract:
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Self-assembly in aqueous solution has been investigated for two Fmoc [Fmoc = N-(fluorenyl)-9-methoxycarbonyl] tetrapeptides comprising the RGDS cell adhesion motif from fibronectin or the scrambled sequence GRDS. The hydrophobic Fmoc unit confers amphiphilicity on the molecules, and introduces aromatic stacking interactions. Circular dichroism and FTIR spectroscopy show that the self-assembly of both peptides at low concentration is dominated by interactions among Fmoc units, although Fmoc-GRDS shows β-sheet features, at lower concentration than Fmoc-RGDS. Fibre X-ray diffraction indicates β-sheet formation by both peptides at sufficiently high concentration. Strong alignment effects are revealed by linear dichroism experiments for Fmoc-GRDS. Cryo-TEM and small-angle X-ray scattering (SAXS) reveal that both samples form fibrils with a diameter of approximately 10 nm. Both Fmoc-tetrapeptides form self-supporting hydrogels at sufficiently high concentration. Dynamic shear rheometry enabled measurements of the moduli for the Fmoc-GRDS hydrogel, however syneresis was observed for the Fmoc-RGDS hydrogel which was significantly less stable to shear. Molecular dynamics computer simulations were carried out considering parallel and antiparallel β-sheet configurations of systems containing 7 and 21 molecules of Fmoc-RGDS or Fmoc-GRDS, the results being analyzed in terms of both intermolecular structural parameters and energy contributions. |
Subject(s):
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-Àrees temàtiques de la UPC::Física::Física molecular -Molecular dynamics -Self-assembly (Chemistry) -Física molecular |
Rights:
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Attribution-NonCommercial-NoDerivs 3.0 Spain
http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
Document type:
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Article - Published version Article |
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