Location: Healthy Processed Foods ResearchTitle: Crystal structure of Cocosin, a potential food allergen from coconut (Cocos nucifera)
|JIN, TENGCHUAN - University Of Science And Technology Of China|
|WANG, CHENG - University Of Science And Technology Of China|
|ZHANG, CAIYING - University Of Science And Technology Of China|
|CHEN, YU-WEI - Illinois Institute Of Technology|
|GUO, FENG - Illinois Institute Of Technology|
|HOWARD, ANDREW - Illinois Institute Of Technology|
|CAO, MIN-JIE - Jimei University|
|FU, TONG-JEN - Us Food & Drug Administration (FDA)|
Submitted to: Journal of Agricultural Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2017
Publication Date: 7/17/2017
Citation: Jin, T., Wang, C., Zhang, C., Chen, Y., Guo, F., Howard, A., Cao, M., Fu, T., Mchugh, T.H., Zhang, Y. 2017. Crystal structure of Cocosin, a potential food allergen from coconut (Cocos nucifera). Journal of Agricultural Chemistry. 65:7560-7568.
Interpretive Summary: Coconut is a very important crop in tropical regions, and virtually every part of the palm tree has economic values. Coconut extract or the coconut milk is an important part of daily diets in many regions of the world. Unfortunately, coconut allergy cases, some fatal, have been reported. Coconut is one of the allergen sources that is required to be declared on the food label by the Food Allergen Labeling and Consumer Protection Act of 2004 if it is one of the ingredients. Information about coconut allergens is very limited. This study reports the characterization of a coconut allergen and the determination of its crystal structure. The reagents generated and the information obtained in this study may be used to guide future research in understanding the allergenicity of food allergens and in enhancing the safe use of tree nuts.
Technical Abstract: Coconut (Cocos nucifera) is an important palm tree. Coconut fruit is widely consumed. The most abundant storage protein in coconut fruit is cocosin, which belongs to the 11S globulin family. It is one of the major allergens in coconut. Cocosin was crystallized nearly a century ago, but its structure remains unknown. By optimizing crystallization conditions and cryoprotectant solutions, we were able to obtain cocosin crystals that diffracted to 1.85 Å. The cocosin gene was cloned from genomic DNA purified from dry coconut tissue. The deduced protein sequence from the predicted cocosin coding sequence was used to guide model building and structure refinement. The structure of this coconut allergen was determined, for the first time, which revealed typical 11S globulin features of hexameric assembling of a double doughnut disk.