Structural Analysis and Sensitization Prediction of the Allergic Proteins Ana o 2 and Ana o 3 in Cashew Nuts

In order to definite the molecular structure and allergic characteristics of cashew nuts, the main allergic proteins were isolated and purified by organic solvent defatting, salting out, dialysis and Sephadex G-150 gel. The allergenic proteins were definitely by UV, BCA kit, SDS-PAGE and Western-Blotting. The amino acid sequence and the DNA sequence of cashew allergic protein were obtained by using the NCBI database and protein mass spectrum sequencing. The structure of cashew allergic protein was predicted by DNAstar bio-information software and circular dichroism (CD). The results showed that the Ana o 2 and Ana o 3 were the main cashew allergenic proteins with molecular weight of 33 and 17 kD. The results of CD and Protean program in DNAstar predicted that there were α-helical, β-folded regions and corner regions which was a hydrophilic protein with strong sensitization because of the β-corners and random curls were found in 54% in Ana o 2. The secondary structure had only a small amount of β-folded region and corner region, accounted for 12%, but had mainly α-helix and random coil structure. It was also hydrophilic allergic protein, and the formation of allergenic epitopes was relatively weak. This study would provide reference for further clarifying the structure of the main allergens of natural cashew nuts and exploring the sensitization mechanism of cashew nuts.