Comparison of the binding affinity of the APN4 receptor in Helicoverpa armigera (Hübner) to the Cry1Ac and Cry2Aa insecticidal proteins
Author of the article:YUAN Xiang-Dong1** GE Zhao-Hong2** XIAO Yu-Tao1 LIANG Ge-Mei1***
Author's Workplace：1. State Key Laboratory of Insect Pests and Plant Diseases, Institute of Plant Protection, Chinese Academy ofAgricultural Sciences, Beijing 100193, China; 2. College of Plant Protection, Northwest Agriculture and Forestry University, Yangling 712100, China
Key Words：Helicoverpa armigera, Bacillus thuringiensis, aminopeptidase N, binding dynamics
Abstract： [Objectives] Bt (Bacillus thuringiensis) insecticidal proteins have been widely adopted to control agricultural pests because of their high target specificity. The binding of a Bt insecticidal protein to its specific receptor in the insect midgut plays a key role in the insecticidal action process. Aminopeptidase N (APN) is one of the major Bt protein receptors. To better characterize the molecular mechanism underlying the insecticidal activity of different Bt insecitcidal proteins, and lay the foundation for Bt resistance management and novel Bt insecticidal protein development, we analyzed the binding affinity of aminopeptidase N4 (APN4) to the Cry1Ac and Cry2Aa insecitcidal proteins in Helicoverpa armigera. [Methods] The binding affinity of aminopeptidase N4 (APN4) was assessed using ligand blot analysis and an ELISA binding assay, respectively. [Results] The results show that recombinant APN4 could bind to both Cry1Ac and Cry2A; their respective dissociation constants were 46.7 nmol/L and 26.5 nmol/L. [Conclusion] The results suggest that there was no significant difference in the binding affinity of APN4 to Cry1Ac and Cry2Aa in H. armigera.