Bioinformatics-based Analyses and B/Th Cell Epitope Prediction of Mugwort Pollen Allergen Art v 1 Protein

To analyze the sequence characteristics of mugwort pollen allergen Art v 1 protein and predict its B cell and Th (helper T cell) cell epitopes, the gene sequence and amino acid sequence of Art v 1 protein were obtained by referring to Genebank. ExPASy's Prot Param, TMHMM, DNAstar Protean, Swiss-Model, UCLA-DOE LAB SAVES v6.0, and IEDB were used to analyze and predict physicochemical properties, transmembrane region, secondary structure, tertiary structure, and B cell and Th cell epitopes of the protein.

The Art v 1 protein is composed of 132 amino acid residues, the relative molecular weight is 13404.26, the molecular formula is C₅₈₄H₉₀₃N₁₅₇O₁₈₁S₁₂, pI value is 7.49, the lipid solubility index is 41.59, and the hydrophilic index is -0.454, which is considered as hydrophilic protein. The instability index (ii) is 78.11, which is classified as an unstable protein. The N-terminus of the protein has an α-helical transmembrane region, which is located in the 5-27 amino acid residue sequence, and the 1-24 position is the signal peptide sequence. There are random coil, β-turn, α-helix, and β-sheet, and it also contains hydrophilic region, flexible region, and surface accessibility region structures.

The prediction results of tertiary structure are consistent with the analysis results of secondary structure. Five dominant B cell epitopes were predicted, which were Art v 1 71-87, Art v 1 33-49, Art v 1 104-120, Art v 1 95-111, and Art v 1 86-102. There were five Th cell dominant epitopes, which were Art v 1 2-16, Art v 1 3-17, Art v 1 4-18, Art v 1 5-19, and Art v 1 6-20. The Art v 1 protein is predicted to have good antigenicity due to the presence of B cell and Th cell epitopes.