Construction Of 3D Interaction Moleculer Models Of Cantharidin With Alkaline Phosphatases From Helicoverpa Armigera And Plutella Xylostella

In this study, alkaline phosphatases of Helicoverpa armigera and Plutella xylostella are used as materials, through the computer-aided drug design technology,a perfect three dimensional molecular model concerning the interaction between cantharidin with alkaline phosphatases of Helicoverpa armigera and Plutella xylostella is established,and to analyze the molecular interaction between alkaline phosphatases and cantharidin. we have developed an interactive model by construction of the chemical activity of small molecules and biological macromolecule conformation cavity interaction between flexible residues, providing a novel idea for optimization of biological pesticides to carry out pilot from the perspective of chemical selectivity of small molecules interact with biological macromolecules and some enlightenment for drug design as well. In this study, results from cantharidin with alkaline phosphatases the binding free energy calculation and experimental results show linear correlation further indicating the reliability of this molecular model study. The results can be applied in cantharidin class structure optimization of biological pesticides and in the directed molecular design of new biological pesticide.As alkaline phosphatases in various species are highly conserved, through homology modeling we can learn more about the relationship between structure and function of AKP1 and AKP, which further helps to find new bio-pesticide lead compounds and improve the design of cantharidin class of biological pesticides.The three-dimensional structure of alkaline phosphatases models were constructed by homology modeling using X-ray diffraction structure of 1.92 ? in Northern shrimp （Pandalus borealis） and 1.90 ? in Human placenta （Placenta hominis） as a template respectively,and the models were verified by ProCheck and Profile₃D. The homology modeling model bases on the template structure and bears high similarity with the template structure, therefore the selection of the template with high homology and similarity in functionality is very important.But there are some functional differences between the constructed model structure and the template because of the differences in the composition of the key amino acid residues in the active site. Meanwhile, we also constructed the solvation model of AKP1 and AKP,with molecular mechanics energy minimization method, we have found tiny molecular conformation energy system of AKP1 and AKP, reducing the unreasonable spatial positions in this system,to amend the model and further the subsequent molecular docking work.The MD simulation was introduced to the construction of AKP1 model, which simulated Helicoverpa armigera alkaline phosphatase 5ns movement in solution. The X-ray data of the single crystal of cantharidin was analyzed by the SHELXL, followed by full-matrix least squares refinement by single crystal diffraction data of the final unit cell parameters, and calculated the cell space coordinates of each atom that generated the exact three-dimensional molecular crystal structure,Mercury will be the use of numerical and mathematical symbols into cantharidin molecule high-resolution three-dimensional model, and this model that was Minimization will be the initial ligand structure in the next Docking work.The atomic elements coordinates with the active center of AKP1 was determined by using the ligand cloning technology. The modeling structure of AKP is only part of whole because of its sequence from GenBank was partial. The atomic elements coordinates with the active center of AKP was generated after the ligand cloning. Although Autogrid program was applicated to generate the BOX to cover AKP, not included AKP structure.Then, the atomic elements coordinates with the active center of AKP was analyzed by LGA algorithm. The interaction models were constructed by Docking between cantharidin with AKP1 and AKP, we selected Autodock for Docking studies. Combined with Lamarckian genetic algorithm （LGA） and Solis & Wets local energy search method,search low-energy binding conformation,semi-empirical potential function as an energy scoring function, selected several lowest energy of representative conformation among the cluster after clusting the Docking conformation.Chose the conformation that have a better effect with the key amino acid residues to be the final binding conformation in active center.Through the analysis of complex structures, we obtained the binding model between cantharidin with AKP1 and AKP, the main interactions role as the polar bond the hydrophobic bond and hydrogen bond, found representation for interaction model of cantharidin with the key amino acids, reveals the inhibition mechanism of cantharidin by the atomic level.