Self-assembly of Gliadin protein modulated by pH.

Gliadin, a protein present in wheat, rye and barley is not fully degraded by humans, leading to allergies, gluten sensitivity and celiac disease.(1,2,3).It has been hypothesized that increased intestinal permeability is an early event in celiac disease pathogenesis (4) but it is completely unknown what endows gliadin the unusual proteolytic resistance. From the physicochemical point of view, this protein is known to be soluble in alcohol solutions in a low percentage and it could be isolated from flour by dilute acetic acid extraction. By this procedure is have been demonstrated the formation of fibrils depending on ionic strength (5). Under different aqueous solutions conditions much less is known. Herein, it is present the evaluation of gliadin protein under different pHs and ionic strength in water. We obtained the solubility of a mix of commercial gliadin proteins under basic and acid conditions varying the temperature. It has been observed the importance of the pH and the temperature in order to form different self-assembly structures. At physiological pH spherical particules of 1-2μm of diameter were detected by electron microscopy. We hypothesize that the observed self-assembly process and the formation of supramolecular structures depending on pH could a be a special feature in order to understand the unusual proteolytic resistances. Taking into account that gastrointestinal environment is highly dynamic(6) in health and disease , recent insights on the potential of intestinal bacteria to influence human health, our results may help to understand Gliadin intolerance. A supramolecular evaluation by different Spectroscopies (UV-Vis and Fluorescence) and Electron Microscopy (SEM, TEM) is presented. References: 1).Hadjivassiliou, M., Williamson, C. A., Woodroofe, N. ,Trends Immunol.,25, 578-582 (2004). 2).Rubio-Tapia, A. , Murray, J. A. ,Curr. Opin. Gastroenterol., 26, 116-122 (2010). 3).Shan, L. et. al. ,Science, 297, 2275-2279 (2002). 4).Fassano, A. , Shea-Donohue, T., Nat. Clin. Pract. Gastroenterol. & Hepatol., 2, 416-422 (2005) 5).Kasarda, D., Bernardin, J.E., Thomas, R., Nature, 203-205 (1967). 6).Possemiers, S., Grootaert, C., Curr Pharm Des.,15(18):2051-65 (2009).