title: Molecular modeling application on hapten epitope prediction: an enantioselective immunoassay for ofloxacin optical isomers.
abstract: To deepen our understanding of the physiochemical principles that govern hapten-antibody recognition, ofloxacin enantiomers were chosen as a model for epitope prediction of small molecules. In this study, two monoclonal antibodies (mAbs) mAb-WR1 and mAb-MS1 were raised against R-ofloxacin and S-ofloxacin, respectively. The enantioselective mAbs have a high sensitivity and specificity, and the enantioselectivity is not affected by heterologous coating format reactions. The epitopes of the ofloxacin isomers were predicted using the hologram quantitative structure-activity relationship (HQSAR) and comparative molecular field analysis (CoMFA) approaches. The results consistently show that the epitope of the chiral hapten should be primarily composed of the oxazine ring and the piperazinyl ring and mAbs recognize the hapten from the side of this moiety. The enantioselectivity of mAbs is most likely due to the steric hindrance caused by the stereogenic center of the epitope. Modeling of chiral hapten-protein mimics reveals that ofloxacin isomers remain upright on the surface of the carrier protein. Suggestions to improve the enantioselectivity of antibodies against ofloxacin isomers were also proposed. This study provided a simple, efficient, and general method for predicting the epitopes of small molecules via molecular modeling. The epitope predictions for small molecules may create a theoretical guide for hapten design.
authors: Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China.
authors: Hongtao
authors: H
authors: Mu
authors: Hongtao
authors: H
authors: Lei
authors: Baoling
authors: B
authors: Wang
authors: Zhenlin
authors: Z
authors: Xu
authors: Chijian
authors: C
authors: Zhang
authors: Li
authors: L
authors: Ling
authors: Yuanxin
authors: Y
authors: Tian
authors: Jinsheng
authors: J
authors: Hu
authors: Yuanming
authors: Y
authors: Sun
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology; D005260:Female; D006241:Haptens / Q000737:chemistry* / Q000276:immunology; D007118:Immunoassay / Q000379:methods*; D007536:Isomerism; D064704:Levofloxacin / Q000032:analysis / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D015394:Molecular Structure; D015242:Ofloxacin / Q000032:analysis / Q000737:chemistry / Q000276:immunology*; D021281:Quantitative Structure-Activity Relationship; D013237:Stereoisomerism
chemical_list: D000900:Anti-Bacterial Agents; D000911:Antibodies, Monoclonal; D000939:Epitopes; D006241:Haptens; D064704:Levofloxacin; D015242:Ofloxacin