Interaction of alpha-gliadin with poly(HEMA-co-SS): structural characterization and biological implication.
The wheat gluten protein alpha-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 alpha-gliadin and poly(HEMA-co-SS) concentrations on alpha-gliadin structure was studied using spectroscopic techniques and dynamic light scattering. In 70% ethanol or 0.06M HCl (pH 1.2), alpha-gliadin was found to self-associate upon increasing its concentrations and displayed decreased alpha-helical content and increased beta-turn and beta-sheet contents. At pH 1.2, alpha-gliadin interacted with poly(HEMA-co-SS) to form supra-molecular complex particles. Poly(HEMA-co-SS) induced alpha-gliadin structural changes that mimicked those obtained by varying the protein concentration in pure solution. At pH 6.8, alpha-gliadin was poorly soluble and formed large particles but alpha-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 alpha-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)/alpha-gliadin interaction and the polymer as alpha-gliadin sequestering agents in the supportive treatment of celiac disease.
Liang
Li
L
Institut de Recherche sur les Nutraceutiques et les Aliments Fonctionnels, Université Laval, Québec, QC, Canada.
Pinier
Maud
M
Leroux
Jean-Christophe
JC
Subirade
Muriel
M
D002942:Circular Dichroism; D005903:Gliadin / Q000737:chemistry*; D009391:Nephelometry and Turbidimetry; D010455:Peptides / Q000737:chemistry; D011073:Polyamines / Q000737:chemistry*; D011102:Polyhydroxyethyl Methacrylate / Q000031:analogs & derivatives* / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
D010455:Peptides; D011073:Polyamines; C056971:poly(2-hydroxyethyl methacrylate)-polyamine graft copolymer; C011083:polyproline; D011102:Polyhydroxyethyl Methacrylate; D005903:Gliadin