Interaction of α-gliadin with poly(HEMA-co-SS): Structural characterization and biological implication

The wheat gluten protein α‐gliadin, a well known trigger of celiac disease, can be complexed by random copolymers of hydroxyethyl methacrylate (HEMA) and sodium 4‐styrene sulfonate (SS). In this work, influence of α‐gliadin and poly(HEMA‐co‐SS) concentrations on α‐gliadin structure was studied using spectroscopic techniques and dynamic light scattering. In 70% ethanol or 0.06M HCl (pH 1.2), α‐gliadin was found to self‐associate upon increasing its concentrations and displayed decreased α‐helical content and increased β‐turn and β‐sheet contents. At pH 1.2, α‐gliadin interacted with poly(HEMA‐co‐SS) to form supra‐molecular complex particles. Poly(HEMA‐co‐SS) induced α‐gliadin structural changes that mimicked those obtained by varying the protein concentration in pure solution. At pH 6.8, α‐gliadin was poorly soluble and formed large particles but α‐helix is still main secondary structure. The influence of the polymer on protein structure was weaker at neutral than acidic pH. Interaction with poly(HEMA‐co‐SS) disrupted α‐gliadin conformation and self‐association to form new complex particles at neutral pH. This study provides insight into the mechanism of poly(HEMA‐co‐SS)/α‐gliadin interaction and the polymer as α‐gliadin sequestering agents in the supportive treatment of celiac disease. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 169–178, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com