Computer-aided molecular modeling study on antibody recognition of small molecules: an immunoassay for triazine herbicides.

Most immunoassays for determination of small molecules are still designed on the basis of the “trial and error” method, due to the lack of understanding of antibody recognition. In the present study, we developed a heterologous indirect competitive enzyme-linked immunosorbent assay for determination of triazine herbicides, with limits of detection for 11 triazines ranging from 0.05 to 29.4 μg/L. Mechanisms of the antigen–antibody interaction were studied by computer-aided molecular modeling (CAMM)-based quantitative structure–activity relationship analyses. Co-effects of the analytes’ substructural hydrophobic, electrostatic, and steric fields on antibody recognition were further revealed. Hydrophobicity of the antigens was demonstrated to have the most important impact. Even less exposed substituents provided hydrophobic force to the antigen–antibody interaction. Dislocated orientation of analyte functional groups could lead to steric hindrance and hydrophobic misleading of antibody recognition. This may...