Different Binding Modes of Free and Carrier-Protein-Coupled Nicotine in a Human Monoclonal Antibody
Different Binding Modes of Free and Carrier-Protein-Coupled Nicotine in a Human Monoclonal Antibody
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DOI：
10.1016/j.jmb.2011.10.042
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发表时间：
2012-01-06
影响因子：
5.6
通讯作者：
Maurer, Patrik
中科院分区：
文献类型：
--
作者：
Tars, Kaspars;Kotelovica, Svetlana;Maurer, Patrik
尼古丁是烟草的主要成瘾成分。用尼古丁特异性抗体阻断它从肺到大脑的通道是治疗吸烟成瘾的一种有希望的方法。我们已经确定了尼古丁的晶体结构结合的Fab片段的完全人单克隆抗体（mAb）在1.85埃分辨率。尼古丁几乎完全（>99%）埋在重链和轻链可变结构域之间的界面中。mAb的高亲和力是电荷-电荷相互作用、氢键和几种疏水接触的结果。此外，类似于大脑中的烟碱乙酰胆碱受体，吡咯烷电荷和附近的芳香侧链之间存在两个阳离子-π相互作用。mAb对尼古丁与可替宁（尼古丁的主要代谢产物，仅一个氧原子不同）的选择性是由结合位点的空间限制引起的。从用尼古丁载体蛋白缀合物疫苗免疫的个体的B细胞中分离rnAb。令人惊讶的是，尼古丁以与尼古丁-载体蛋白缀合物的结合不相容的取向结合至Fab片段。与用于生产缀合物疫苗的尼古丁-接头衍生物复合的Fab片段的结构揭示了尼古丁部分的吡啶环的类似位置，但吡咯烷环旋转了约180度。这允许接头部分到达Fab表面，同时保持与尼古丁部分的高亲和力相互作用。(C)2011爱思唯尔有限公司保留所有权利。
Nicotine is the principal addictive component of tobacco. Blocking its passage from the lung to the brain with nicotine-specific antibodies is a promising approach for the treatment of smoking addiction. We have determined the crystal structure of nicotine bound to the Fab fragment of a fully human monoclonal antibody (mAb) at 1.85 angstrom resolution. Nicotine is almost completely (>99%) buried in the interface between the variable domains of heavy and light chains. The high affinity of the mAb is the result of a charge-charge interaction, a hydrogen bond, and several hydrophobic contacts. Additionally, similarly to nicotinic acetylcholine receptors in the brain, two cation-pi interactions are present between the pyrrolidine charge and nearby aromatic side chains. The selectivity of the mAb for nicotine versus cotinine, which is the major metabolite of nicotine and differs in only one oxygen atom, is caused by steric constraints in the binding site. The rnAb was isolated from B cells of an individual immunized with a nicotine carrier protein conjugate vaccine. Surprisingly, the nicotine was bound to the Fab fragment in an orientation that was not compatible with binding to the nicotine-carrier protein conjugate. The structure of the Fab fragment in complex with the nicotine-linker derivative that was used for the production of the conjugate vaccine revealed a similar position of the pyridine ring of the nicotine moiety, but the pyrrolidine ring was rotated by about 180 degrees. This allowed the linker part to reach to the Fab surface while high-affinity interactions with the nicotine moiety were maintained. (C) 2011 Elsevier Ltd. All rights reserved.