Maeda H, Schmidt-Kessen A, Engel J, Jaton J C
Biochemistry. 1977 Sep 6;16(18):4086-9. doi: 10.1021/bi00637a023.
Temperature-jump experiments were performed with di-, tetra-, and hexasaccharides derived from type III pneumococcal polysaccharide using a homogeneous corresponding antibody IgG 45-394. A decrease in stability of the oligosaccharide-antibody complexes with decreasing chain length was observed and entirely reflected in the decrease of the association rate constants which were 1.7 X 10(4) M-1 s-1 for the di-, 3.7 X 10(5) M-1 s-1 for the tetra-, and 1.1 X 10(6) M-1 s-1 for the hexasaccharide at 23 degrees C. The dissociation rate constants for all oligomers were about 12 s-1. This marked chain-length dependence of the association rate constants as well as their low values are unexpected for a single binding step. A mechanism is proposed which consists of a fast formation of a labile oligosaccharide-antibody precomplex followed by a slow isomerization step which is induced by the oligosaccharide ligands but which is chain-length independent.
使用同源对应抗体IgG 45 - 394对源自III型肺炎球菌多糖的二糖、四糖和六糖进行了温度跃升实验。观察到寡糖 - 抗体复合物的稳定性随链长的减小而降低，这完全反映在缔合速率常数的降低上，在23℃时，二糖的缔合速率常数为1.7×10⁴ M⁻¹ s⁻¹，四糖为3.7×10⁵ M⁻¹ s⁻¹，六糖为1.1×10⁶ M⁻¹ s⁻¹。所有寡聚物的解离速率常数约为12 s⁻¹。缔合速率常数对链长的这种显著依赖性及其低值对于单一结合步骤来说是出乎意料的。提出了一种机制，该机制包括不稳定的寡糖 - 抗体预复合物的快速形成，随后是由寡糖配体诱导的缓慢异构化步骤，但该步骤与链长无关。
