Most immunoassays for determination of small molecules are still designed on the basis of the 鈥渢rial and error鈥?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 渭g/L. Mechanisms of the antigen鈥揳ntibody interaction were studied by computer-aided molecular modeling (CAMM)-based quantitative structure鈥揳ctivity relationship analyses. Co-effects of the analytes鈥?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鈥揳ntibody interaction. Dislocated orientation of analyte functional groups could lead to steric hindrance and hydrophobic misleading of antibody recognition. This may happen even when the antigens contained the same substituent as the hapten. Frontier orbital energies also affect the reaction significantly. This study highlights of the power of CAMM-based analyses, providing insights into antibody recognition of small molecules.
Keywords:
Triazine; hapten; immunoassays; molecular modeling; antibody recognition