Structural Basis of Enhanced Crystallizability Induced by a Molecular Chaperone for Antibody Antigen-Binding Fragments
Structural Basis of Enhanced Crystallizability Induced by a Molecular Chaperone for Antibody Antigen-Binding Fragments
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DOI：
10.1016/j.jmb.2017.12.010
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发表时间：
2018-02-02
影响因子：
5.6
通讯作者：
Julien, Jean-Philippe
中科院分区：
文献类型：
--
作者：
Ereno-Orbea, June;Sicard, Taylor;Julien, Jean-Philippe
单克隆抗体构成了治疗癌症和免疫疾病的最大药物组之一，并且指导针对传染病的疫苗的设计。片段抗原结合（Fab）由于其相对低的柔性而优于单克隆抗体用于抗体抗原复合物的结构表征。尽管如此，由于互补决定区的表面特征和可变结构域和恒定结构域之间的铰链区中的残余柔性，Fab通常仍然具有结晶的挑战性。在这里，我们使用了对人κ轻链特异性的可变重链（VHH）结构域来辅助三种治疗性Fab的结构测定，所述治疗性Fab自身不结晶。我们表明，这种配体改变了抗体配体复合物的表面性质，并降低其聚集温度，有利于结晶。VHH结晶分子伴侣还将Fab的柔性铰链限制在窄的角度范围内，并且因此独立于可变区。我们的研究结果有助于抗体结构测定的有价值的方法，并提供生物物理学的洞察大分子结晶的原则。(C)2017爱思唯尔有限公司版权所有
Monoclonal antibodies constitute one of the largest groups of drugs to treat cancers and immune disorders, and are guiding the design of vaccines against infectious diseases. Fragments antigen-binding (Fabs) have been preferred over monoclonal antibodies for the structural characterization of antibody antigen complexes due to their relatively low flexibility. Nonetheless, Fabs often remain challenging to crystallize because of the surface characteristics of complementary determining regions and the residual flexibility in the hinge region between the variable and constant domains. Here, we used a variable heavy-chain (VHH) domain specific for the human kappa light chain to assist in the structure determination of three therapeutic Fabs that were recalcitrant to crystallization on their own. We show that this ligand alters the surface properties of the antibody ligand complex and lowers its aggregation temperature to favor crystallization. The VHH crystallization chaperone also restricts the flexible hinge of Fabs to a narrow range of angles, and so independently of the variable region. Our findings contribute a valuable approach to antibody structure determination and provide biophysical insight into the principles that govern the crystallization of macromolecules. (C) 2017 Elsevier Ltd. All rights reserved.