Crystal structure determination of Scylla paramamosain arginine kinase, an allergen that may cause cross-reactivity among invertebrates.

Shellfish are one of the most common causes of food allergy. Arginine kinase (AK) is known as an important allergen in shellfish. In the present study, AK from crab (Scylla paramamosain) was purified and its crystal structure was determined. A comparison of AK from S. paramamosain to AKs of other species showed high amino acid sequence and secondary structure identity, while the superposition of crystal structures of AKs from different species revealed only slight differences. Similarity of the linear epitope regions among species was observed in the epitope alignment of AKs; conformational epitopes were located in the regions where secondary structure was conserved. The structure of S. paramamosain AK is an accurate template for the analysis of the IgE binding pattern, and the structure conservation and epitope similarity of AKs among species could help to inform our understanding of the cross-reactivity and contribute to the prediction of cross-reactivity related epitopes.
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