| Texto completo | |
| Autor(es): |
Decandio, Carla C.
[1]
;
Silva, Emerson R.
[2, 1]
;
Hamley, Ian W.
[2]
;
Castelletto, Valeria
[2]
;
Liberato, Michelle S.
[1]
;
Oliveira, Jr., Vani X.
[1]
;
Oliveira, Cristiano L. P.
[3]
;
Alves, Wendel A.
[1]
Número total de Autores: 8
|
| Afiliação do(s) autor(es): | [1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210580 Santo Andre - Brazil
[2] Univ Reading, Dept Chem, Reading RG6 6AD, Berks - England
[3] Univ Sao Paulo, Inst Fis, BR-05314970 Sao Paulo - Brazil
Número total de Afiliações: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Langmuir; v. 31, n. 15, p. 4513-4523, APR 21 2015. |
| Citações Web of Science: | 21 |
| Resumo | |
A model octapeptide peptide consisting of an alternating sequence of arginine (Arg) and phenylalanine (Phe) residues, namely, {[}Arg-Phe](4), was prepared, and its self-assembly in solution studied. The simple alternating {[}Arg-Phe](4) peptide sequence allows for unique insights into the aggregation process and the structure of the self-assembled motifs. Fluorescence and UV-vis assays were used to determine critical aggregation concentrations, corresponding to the formation of oligomeric species and beta-sheet rich structures organized into both spheroidal aggregates and highly ordered fibrils. Electron and atomic force microscopy images show globular aggregates and long unbranched fibers with diameters ranging from similar to 4 nm up to similar to 40 nm. Infrared and circular dichroism spectroscopy show the formation of beta-sheet structures. X-ray diffraction on oriented stalks show that the peptide fibers have an internal lamellar structure, with an orthorhombic unit cell with parameters a similar to 27.6 angstrom, b similar to 9.7 angstrom, and c similar to 9.6 angstrom. In situ small-angle X-ray scattering (SAXS) shows the presence of low molecular weight oligomers in equilibrium with mature fibers which are likely made up from 5 or 6 intertwined protofilarnents. Finally, weak gel solutions are probed under gentle shear, suggesting the ability of these arginine-rich fibers to form networks. (AU) | |
| Processo FAPESP: | 12/15481-1 - Matrizes poliméricas funcionais preparadas por eletrofiação: Estudos das propriedades estruturais e processos de biodegradação |
| Beneficiário: | Michelle da Silva Liberato |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 14/03514-8 - Investigações estruturais em sistemas-modelo baseados em peptídeos anfifílicos |
| Beneficiário: | Emerson Rodrigo da Silva |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado |
| Processo FAPESP: | 13/12997-0 - Auto-organização hierárquica de peptídeos anfifílicos: mecanismos fundamentais e potenciais aplicações |
| Beneficiário: | Wendel Andrade Alves |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |