Self-Organization of Gliadin Protein at Physiological pH

HERRERA, M.G; VEUTHEY . T; COSTABEL. M.D; SEWALD. N.; DODERO.V.I

Berlin

Conferencia; 6th International Colloids Conference; 2016

Gliadin is a complex protein mixture present in wheat, rye and barley. This protein is not fully degraded by humans, although theoretically it is accessible for the proteolytic enzyme pepsin at 48 sites. It is known that gliadin and some of its proteolytic resistant peptides are responsible for immunological diseases, like celiac disease and gluten sensitivity which are complex immunological disorders with a prevalence of 1% and 7% among the healthy population, respectively. Despite intensive studies, the primary mechanism by which gliadin and its proteolytical resistant fragments cause immunological imbalance and disease still remains to be elucidated. Recently, we showed that gliadin oligomerizes in water at physiological pH. The occurrence of gliadin colloidal nanostructures can explain the up to now unexpected proteolytical resistance, and thus the hypothesis of incapability of digestive enzymes to access to the degradation sites of gliadin is reasonable. Here, we present gliadin oligomers morphology by Cryo-TEM and we provide bioinformatics evidence that validate the oligomerization observed experimentally. Finally, we evaluated the proteolysis of gliadin colloidal structures by pepsin at pH 3 and the physico-chemical evaluation of the resistant fragments by spectroscopic methods is presented.