Development of different platforms would be useful for designing functional antibodies to improve the efficiency of antibody-based drugs. Three-dimensional domain swapping (3D-DS) may occur in the variable region of antibody light chain #4C214A, and a pair of domain-swapped dimers may interact with each other to form a tetramer. In this study, to stabilize the 3D-DS dimer structure in #4C214A, Val2 in strand A (swapping region) and Thr97 in strand G were replaced with Cys residues, generating #4 V2C/T97C/C214A with a Cys2–Cys97 disulfide bond that cross-links strands A and G of different protomers. The #4 V2C/T97C/C214A tetramer did not dissociate into monomers at low protein concentration (6 μM); however, some of the tetramers were converted to monomers by disulfide bond reduction. Two-dimensional free energy profile analysis for the tetramerization of two 3D-DS dimers was performed by molecular dynamics simulation. These results show that disulfide bond introduction is useful for controlling the dimerization/dissociation of the variable region through 3D-DS.

中文翻译：

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二硫键引入抗体轻链结构域交换结构稳定的实验和计算研究


开发不同的平台将有助于设计功能性抗体，以提高基于抗体的药物的效率。三维结构域交换 （3D-DS） 可能发生在抗体轻链 #4C214A 的可变区，一对结构域交换的二聚体可能相互作用形成四聚体。在本研究中，为了稳定 #4C214A 中的 3D-DS 二聚体结构，链 A 中的Val2（交换区）和链G中的Thr97被Cys残基取代，生成具有Cys2-Cys97二硫键的#4 V2C/T97C/C214A，该二硫键可交联不同原构体的链 A 和 G。#4 V2C/T97C/C214A 四聚体在低蛋白浓度 （6 μM） 下不解离成单体;然而，一些四聚体通过二硫键还原转化为单体。通过分子动力学模拟对两个 3D-DS 二聚体的四聚化进行二维自由能分布分析。这些结果表明，二硫键的引入有助于通过 3D-DS 控制可变区的二聚化/解离。