IFISUR   23398
INSTITUTO DE FISICA DEL SUR
Unidad Ejecutora - UE
artículos
Título:
Circular Dichroism and Electron Microscopy Studies in vitro of 33-mer Gliadin Peptide revealed Secondary Structure Transition and Supramolecular Organization
Autor/es:
M. G. HERRERA; F. ZAMARREÑO; M. COSTABEL; H. RITACCO; A. HÜTTEN; N. SEWALD; V. I. DODERO
Revista:
BIOPOLYMERS
Editorial:
JOHN WILEY & SONS INC
Referencias:
Lugar: New York; Año: 2014 vol. 101 p. 96 - 106
ISSN:
0006-3525
Resumen:
Gliadin, a protein present in wheat, rye and barley, undergoes incomplete enzymatic degradation during digestion, producing an immunogenic 33-mer peptide, LQLQPF(PQPQLPY)3PQPQPF. The special features of 33-mer that provoke a break in its tolerance leading to gliadin sensitivity and celiac disease remains elusive. Herein it is reported that 33-mer gliadin peptide was not only able to fold into PPII secondary structure, but also depending on concentration conformational transition and self-assembly proceeded under aqueous condition, pH 7.0. A 33-mer dimer is presented as one initial possible step in the self-assembly process obtained by partial electrostatics charge distribution calculation and molecular dynamics. In addition, electron microscopy experiments revealed supramolecular organization of 33-mer into colloidal nanospheres. In the presence of 1 mM sodium citrate, 1mM sodium borate, 1 mM sodium phosphate buffer, 15 mM NaCl the nanospheres were stabilized, while in water a linear organization and formation of fibrils were observed. It is hypothesized that the self-assembly process could be the result of the combination of hydrophobic effect, intramolecular hydrogen bonding and electrostatic complementarity due to 33-mer high content of proline and glutamine amino acids and its calculated non-ionic amphiphilic character. Although, performed in vitro, our experiments have revealed new features of the 33-mer gliadin peptide that could represent an important and unprecedented event in the early stage of 33-mer interaction with the gut mucosa prior to onset of inflammation. Moreover, these findings may open new perspectives for the understanding and treatment of gliadin intolerance disorders.