ABSTRACT
AscreeningmethodforcriticalaminoacidsinEpitopesusinganti-Epitopeantibodywasdeveloped. The amino acids' frequency of occurrence in Epitopes of shrimp antigen Pen a1 was calculated using MEGA5 software and their conservative property of tropomyosin in SDAP database bank was analyzed using DNAMAN software. Potential critical amino acids based on these two methods were identified, namely Epitope 1 ( K, E, N) , Epitope 2 ( K, L, E) , Epitope 3 ( E, R, D, L, Q) , Epitope 5 ( K, L, Q) . The mutated polypeptides corresponding to these Epitopes in which these critical amino acids were substituted with alanine were synthesized. The IgG binding ability of these mutants was analyzed by competitive immunodot-blot method and indirect ELISA using Epitope antibody to screen the critical amino acids. Experimental results showed that the critical amino acids of the four Epitopes were as follows: Epitope 1 ( Gln ) , Epitope 2 ( Leu and Glu ) , Epitope 3 ( Leu and Asp) , Epitope 5 ( Leu) . The feasibility of this screening method was proved and it also offered a theoretical foundation for research on sensitization mechanism of Pen a1 and desensitization using gene modification.