Molecular Biology at IIT
Nut Allergens
Food Allergies are immune system responses to a food protein. Nut allergies are the most common type of food allergy in the United States. They affect more than 3 million people, primarily children, and are capable of causing allergic reactions ranging from rashes to anaphylactic shock and death. Worldwide, the prevalence of food allergies has increased dramatically. The number of American children suffering from food allergies increased 18 percent in the last 10 years. Researchers are working to determine why food allergies are increasing and to answer other related questions, such as why one child develops an allergy while others do not. Illinois Institute of Technology and National Center for Food Safety and Technology investigators are interested in why some proteins tend to be allergens. There are thousands of proteins in the mature dry seeds of a plant, but only a dozen or fewer are known to be capable of eliciting an allergic response in atopic (predisposed to allergies) individuals from such a food source. Most plant-based food allergens belong to only a few protein families, although proteins are scientifically grouped into thousands of protein families. IIT/NCFST investigators are interested in characterizing peanut and tree nut allergens structurally to understand the physical and chemical properties and biological activities that may play a role in determining or promoting their allergenicity; to understand the structural basis of possible allergic cross-reactivity; and to develop novel agents and vaccines to be used in diagnosis, prognosis, and treatment of food allergies.
IIT Senior Lecturer of Biology Yuzhu Zhang and his team recently reported the crystal structure of a major peanut allergen named Ara h 3 in the journal Molecular Immunology (2009, 46, 1796–804). Zhang’s research is critical for developing agents for diagnosis and new vaccines for the treatment and potentially the prevention of nut allergies. “It’s the first time a crystal structure of a peanut allergen has been characterized,” says Martin Cole, NCFST director. “It provides us with fundamental mechanical information for controlling nut allergens and their response in humans.” Food allergy research will be a major NCFST and IIT focus in the coming years.
A ribbon representation of the crystal structure of the peanut allergen Ara h 3 determined at 1.73 angstrom. (photo courtesy of Yuzhu Zhang)
Through the collaborative efforts of Zhang, Teng-Jen Fu’s team at the NCFST, and IIT Associate Professor Andy Howard, the three-dimensional structure of the almond allergen amandin also has been solved, and a manuscript was submitted for publication earlier in the summer. The atomic coordinates (a way of describing molecular structure) for the peanut allergen and almond allergen have been deposited in the Worldwide Protein Data Bank. The collaborating teams were able to make the breakthroughs in part because they were successful in getting the allergen proteins to crystallize—the major stumbling block in determining protein structure—and used a high-powered X-ray source at Argonne National Laboratory to determine the allergen’s structure. Solving the three-dimensional structure of allergens opens the door to nut allergy therapeutic treatments and vaccines, genetic modification of nuts to be less allergenic or nonallergenic and the alteration of current food-processing methods to reduce or eliminate nut allergenicity.
posted: