Lancet D, Pecht I
Proc Natl Acad Sci U S A. 1976 Oct;73(10):3549-53. doi: 10.1073/pnas.73.10.3549.
The kinetics of hapten binding to the homogeneous immunoglobulin A secreted by the murine plasmacytoma MOPC 460 was investigated by the chemical relaxation method. Two distinct relaxation times were observed in the binding equilibrium with three different haptens. A detailed concentration dependence analysis of relaxation times and amplitudes was performed with the hapten epsilon-N(2,4-dinitrophenyl)-lysine (Dnp-Lys). The results support a mechanism in which two interconvertible conformational states of the protein bind the hapten with different association constants. Hapten binding shifts the equilibrium towards the better binding state. These observations form kinetic evidence for a conformational transition induced in the immunoglobulin by ligand binding to its antigen binding site, and are in line with the allosteric hypothesis for the initiation of physiological functions by antigen-antibody association.
通过化学弛豫方法研究了半抗原与小鼠浆细胞瘤MOPC 460分泌的同源免疫球蛋白A结合的动力学。在与三种不同半抗原的结合平衡中观察到两个不同的弛豫时间。用半抗原ε-N(2,4-二硝基苯基)-赖氨酸（Dnp-Lys）对弛豫时间和振幅进行了详细的浓度依赖性分析。结果支持一种机制，即蛋白质的两种可相互转化的构象状态以不同的缔合常数结合半抗原。半抗原结合使平衡向更好的结合状态移动。这些观察结果构成了配体与其抗原结合位点结合诱导免疫球蛋白构象转变的动力学证据，并且与抗原-抗体缔合引发生理功能的别构假说一致。
