Computerized Molecular Simulation Docking Aided Study On The Specificity Of Ampicillin Residue Detection Immunosensor

With the development of modern animal husbandry and nutritional knowledge, the requirement of animal derived food is becoming more and more highlighting. The nutrients of animal derived food are abundant, they tend to be assimilated and digestedeasily by human. The produce of animal derived food is based on the technology of modern animal husbandry,usage of molecular biosciencesbreeding andcultivating techniquemore and more guarantees livestock-bird growth healthy and the animal husbandry development regularly. On the other hand, unreasonable added beast medicine easily brings aboutveterinary medicine residueproblem of animal derived food safety.As an analytical approach,immunosensor is widely used and studied for its simple-design, high-sensitivity and low-cost. Although there are many research findings, practical application in the market is few mainly for the unreliable performance.The biological recognition and biomolecules immobilization were lots of environmental sensitivity,and effect on the immunosensor performance.Molecular simulation is a molecular lever research approach based on quantum mechanics (QM), molecular mechanics (MM) and strong computation capability of advanced computer. Because of the advantage of decreasing research cost, strengthened safety, detailed knowledge and so on,computational studies have beenused in many different fields.This work aimed to the developmentof penicillin residue detection immunosensor for animal derived food safety, and mainly concerned to the mode of direct detection by immobilized antibody. In order to well understand the efficiency of immobilized antibody,possible reasons of biosensor building and detecting, the BSA blocking, was studied by molecular simulation running on computer. The immobilization of antibody is based on self-assembly monolayer of thioctic acid formed on electrode surface.Different BSA blocking modes were investigatedby detecting the signal withpiezoelectric crystal microbalance.Evaluate and discuss the molecular simulation application possibility of immunosensor research.The main contents and results are summarized as follows.(1) Three different web served protein-protein interaction simulation methods had been used in the study for ampicillin antibody specific evaluation. ClusPro(http://cluspro.bu.edu/), GRAMM-X (http://vakser.bioinformatics.ku.edu/resources/gramm/grammx), FiberDock (http://bioinfo3d.cs.tau.ac.il/FiberDock). These programsprovided an overall interaction of ampicillin antibody and HSA/OVA with similarity and consistency, indicated that ampicillin antibody complementarity determining region is possibly to bind to HSA/OVA in biosensor building process and detection samples.(2) ZDOCK simulation used to further evaluation of docked protein-protein complexes. By contrast with the specific interaction between antibody and antigen (lysozyme and antibody), it is found that the cluster density of non-specific interaction docking complexes is smaller, dock score of these poses are more scattered too. However, non-specific interaction of ampicillin antibody chain A and HSA presented a higher score than lysozyme and antibody, but chain B and HSA given a reasonable low score. Duing to the solvation effects electrostatic and Van der Waals interactions are important to form biological molecules and complexes, including in immune reaction. The formation probability of antibogy-OVA docking complex was lower than antibogy-HSA implying that antibody preparing process may impact on its specific.(3) To analysis the binding complexproperties,the amino acid sequence of ampicillin antibody and other PDB 3D antibody structurewere aligned by BLAST program. The result shown that almost all curial crucialamino acid residues of ampicillin chain A were located in the complex surface.(4) The result of experimental study on different BSA blocking shown that the mass of adsorbing BSA on antibody modified electrode performing concentration and time dependence, mass of immobilized antibody don't displaynegative correlation with BSA mass. It is indicated that the interaction possibility of ampicillin antibody and BSA.(5) Electrochemical characteristics of the immobilization and immune response of different immunosensors with various immobilized antibody and blocking reagentwere determined by cyclic voltammetry. The result showed that the building schema of immunosensor is successful. In addition, cyclic voltammetry (CV) was employed to realize the different blocking processed electrodesdetection of pesticide residues.The more bounded blocking BSA associated, the less ampicillin detected.