Synthesis and Characterization of Cry2Ab–AVM Bioconjugate: Enhanced Affinity to Binding Proteins and Insecticidal Activity
Zhi-Zhen Pan,
Lian Xu,
Yi-Shu Zheng,
Li-Yang Niu,
Bo Liu,
Nan-Yan Fu,
Yan Shi,
Qing-Xi Chen,
Yu-Jing Zhu,
Xiong Guan
Affiliations
Zhi-Zhen Pan
State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Lian Xu
School of Life Sciences, Xiamen University, Xiamen 361005, China
Yi-Shu Zheng
School of Life Sciences, Xiamen University, Xiamen 361005, China
Li-Yang Niu
School of Life Sciences, Xiamen University, Xiamen 361005, China
Bo Liu
Agricultural Bio-Resources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China
Nan-Yan Fu
MOE Key Laboratory for Analytical Science of Food Safety and Biology & Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, College of Chemistry, Fuzhou University, Fuzhou 350116, China
Yan Shi
School of Life Sciences, Xiamen University, Xiamen 361005, China
Qing-Xi Chen
School of Life Sciences, Xiamen University, Xiamen 361005, China
Yu-Jing Zhu
Agricultural Bio-Resources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China
Xiong Guan
State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
Bacillus thuringiensis insecticidal proteins (Bt toxins) have been widely used in crops for agricultural pest management and to reduce the use of chemical insecticides. Here, we have engineered Bt toxin Cry2Ab30 and bioconjugated it with 4”-O-succinyl avermectin (AVM) to synthesize Cry2Ab−AVM bioconjugate. It was found that Cry2Ab−AVM showed higher insecticidal activity against Plutella xylostella, up to 154.4 times compared to Cry2Ab30. The binding results showed that Cry2Ab−AVM binds to the cadherin-like binding protein fragments, the 10th and 11th cadherin repeat domains in the P. xylostella cadherin (PxCR10−11), with a much higher affinity (dissociation equilibrium constant KD = 3.44 nM) than Cry2Ab30 (KD = 28.7 nM). Molecular docking suggested that the macrolide lactone group of Cry2Ab−AVM ligand docking into the PxCR10−11 is a potential mechanism to enhance the binding affinity of Cry2Ab−AVM to PxCR10−11. These findings offer scope for the engineering of Bt toxins by bioconjugation for improved pest management.
