title: Immunoassay for phenylurea herbicides: application of molecular modeling and quantitative structure-activity relationship analysis on an antigen-antibody interaction study.
abstract: An indirect competitive enzyme-linked immunosorbent assay (icELISA) for 12 phenylurea herbicides (PUHs) was established with the half-maximum inhibition concentration (IC(50)) of 1.7-920.7 μg L(-1). A method of computer-aided molecular modeling was established in quantitative structure-activity relationship (QSAR) studies to obtain a deeper insight into the PUHs' antibody interactions on how and which molecular properties of the analytes quantitatively affect the antibody recognition. A two-dimensional (2D)-QSAR model based on the Hansch equation and a hologram QSAR (HQSAR) model were constructed, and both showed highly predictive abilities with cross-validation q(2) values of 0.820 and 0.752, respectively. It was revealed that the most important impact factor of the antibody recognition was the PUHs' hydrophobicity (log P), which provided a quadratic correlation to the antibody recognition. Hapten-carrier linking groups were less exposed to antibodies during immunization; thus, groups of the analytes in the same position were generally considered to be less contributive to antibody recognition during immunoassay. But the results of substructure-level analysis showed that these groups played an important role in the antigen-antibody interaction. In addition, the frontier-orbital energy parameter E(LUMO) was also demonstrated as a related determinant for this reaction. In short, the result demonstrated that the hydrophobicity and the lowest unoccupied molecular orbital energy (E(LUMO)) of PUH molecules were mainly responsible for antibody recognition.
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Yuan
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.forename: Enmei
authors.initials: E
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Sheng
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Angus
authors.initials: A
authors.lastname: Crossan
authors.forename: Ivan
authors.initials: I
authors.lastname: Kennedy
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000941:Antigens / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006540:Herbicides / Q000032:analysis* / Q000276:immunology; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D010671:Phenylurea Compounds / Q000032:analysis* / Q000276:immunology; D021281:Quantitative Structure-Activity Relationship; D011789:Quantum Theory
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D006540:Herbicides; D010671:Phenylurea Compounds