Computational Characterisation and Identification of Peptides for in silico Detection of Potentially Celiac-Toxic Proteins

Abstract

This work reports on in silico analysis of celiac-toxic peptide occurrence in proteins. The toxic properties of celiac disease are linked to the presence of specific amino acid sequences and the properties of their environment. The analysed celiac-toxic peptides were found to be predominated by unordered structures of random coil and β-turns. Proline and glutamine-rich amino acid sequences from hydrophilic β-turns were exposed on the surface of the precursor proteins. The sequence motifs represented by gluten peptide epitopes or tetrapeptides with surroundings seem to represent an immunodominant structure. The application of MS BLAST software enabled identification of a few fragments with high degrees of identity to the toxic peptides in one protein sequence. Rich sources of celiac-disease-potentiating peptides were wheat gliadins, barley hordeins and rye secalins as well as low-molecular weight fractions of glutenin. In addition, amino acid sequences with a high degree of identity to the toxic peptides examined were detected in maize zein, oat avenin, protein of rice, yeast and chicken muscles, as well as β-casein and galanin.