Benzo[a]pyrene, which is produced during the incomplete combustion of organic material, is an abundant noxious pollutant because of its carcinogenic metabolic degradation products. The high-affinity (K_D≈3 nm) monoclonal antibody 22F12 allows facile bioanalytical quantification of benzo[a]pyrene even in complex matrices. We report the functional and X-ray crystallographic analysis of 22F12 in complex with 3-hydroxybenzo[a]pyrene after cloning of the V-genes and production as a recombinant Fab fragment. The polycyclic aromatic hydrocarbon is bound in a deep pocket between the light and heavy chains, surrounded mainly by aromatic and aliphatic amino acid side chains. Interestingly, the hapten–antibody interface is less densely packed than expected and reveals polar, H-bond-like interactions with the polycyclic aromatic π-electron system, which may allow the antibody to maintain a large, predominantly hydrophobic binding site in an aqueous environment while providing sufficient complementarity to its ligand.

中文翻译：

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高亲和力抗体对苯并[a] py的紧密分子识别

在有机材料不完全燃烧过程中产生的苯并[ a ] py由于其致癌的代谢降解产物而成为一种有毒的污染物。高亲和力（ķ _d ≈3Ñ米）单克隆抗体22F12允许苯并容易生物分析定量[一个]芘即使在复杂的矩阵。我们报告了22 F12与3-羟基苯并[ a]的复合物的功能和X射线晶体学分析克隆V基因后产生] py，并以重组Fab片段的形式产生。多环芳族烃结合在轻链和重链之间的深袋中，主要被芳族和脂族氨基酸侧链包围。有趣的是，半抗原与抗体的界面堆积不如预期的那么紧密，并且揭示了与多环芳族π电子系统的极性，H键样相互作用，这可能会使抗体在水性环境中维持较大的疏水结合位点同时为其配体提供足够的互补性。