Circular Dichroism and Electron Microscopy Studies In Vitro of 33-mer Gliadin Peptide Revealed Secondary Structure Transition and Supramolecular Organization

• Autores: Herrera, Maria Georgina; Zamarreño, Fernando; Costabel, Marcelo Daniel; Ritacco, Hernán Alejandro; Hütten, Andreas; Sewald, Norbert; Dodero, Veronica Isabel
• Año de publicación: 2014
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: 33-Mer; Gliadin Peptide; Circular-Dichroism; Electron Microscopy; Supramolecular Organization; Gliadin Intolerance
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Gliadin, a protein present in wheat, rye, and barley, undergoes incomplete enzymatic degradation during digestion, producing an immunogenic 33-mer peptide, LQLQPF(PQPQLPY)3 PQPQPF. 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 polyproline II secondary structure but also depending on concentration resulted in conformational transition and self-assembly under aqueous condition, pH 7.0. A 33-mer dimer is presented as one initial possible step in the self-assembling 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 mMsodium citrate, 1 mMsodium borate, 1 mMsodium phosphate buffer, 15 mMNaCl, the nanospheres were stabilized, whereas in water, a linear organization and formation of fibrils were observed. It is hypothesized that the self-assembling process could be the result of the combination of hydrophobic effect, intramolecular hydrogen bonding, and electrostatic complementarity due to 33-mer’s high content of proline and glutamine amino acids and its calculated nonionic amphiphilic character. Although, performed in vitro, these 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.
Fil: Herrera, Maria Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Bahía Blanca. Instituto de Química del Sur; Argentina.;
Fil: Zamarreño, Fernando. Universidad Nacional del Sur. Departamento de Física; Argentina;
Fil: Costabel, Marcelo Daniel. Universidad Nacional del Sur. Departamento de Física; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Bahía Blanca. Instituto de Física del Sur; Argentina;
Fil: Ritacco, Hernán Alejandro. Universidad Nacional del Sur. Departamento de Física; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Bahía Blanca. Instituto de Física del Sur; Argentina;
Fil: Hütten, Andreas. Universitat Bielefeld; Alemania;
Fil: Sewald, Norbert. Universitat Bielefeld; Alemania;
Fil: Dodero, Veronica Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Bahía Blanca. Instituto de Química del Sur; Argentina.; Universitat Bielefeld; Alemania; Universidad Nacional del Sur. Departamento de Física; Argentina;