Lee J S, Dombroski D F, Mosmann T R
Biochemistry. 1982 Sep 28;21(20):4940-5. doi: 10.1021/bi00263a017.
Fab fragments from hybridoma HEd 10 [Lee, J. S., Lewis, J.R., Morgan, A.R., Mosmann, T.R., & Singh, B. (1981) Nucleic Acids Res. 9, 1707-1721] were prepared in large amounts by papain digestion of the immunoglobulin G (IgG) fraction from ascites fluid. Binding data were generated by a fluorescence quenching technique, and binding constants [K(0)] were estimated from Scatchard plots. The Fab fragments bound tightly to poly(dT) [K(0) = 12.7 X 10(6) M-1], and analysis of binding constants for the series p(dT)2 to p(dT)17 showed that the recognition sequence consisted of four consecutive residues. The effect of ionic strength on the interaction suggested that only two phosphates were involved. Binding constants for poly(dU), poly[d(brU)], poly[d(brC)], and poly(rU) were 1.0 X 10(6) M-1, 18.8 X 10(6) M-1, 0.5 X 10(6) M-1, and less than 0.5 X 10(6) M-1, respectively, implicating the involvement of the 3, 4, and 5 positions of the pyrimidine ring as well as the deoxyribose sugar in the recognition process. At high ionic strength (0.5 M) K(0) for whole IgG binding to poly(dT) was 75 X 10(6) M-1 compared to a value of 1.1 X 10(6) M-1 for the Fab fragment. These results may have implications for the tissue damage caused by DNA-containing immune complexes in systemic lupus erythematosus.
通过用木瓜蛋白酶消化腹水液中的免疫球蛋白G（IgG）组分，大量制备了来自杂交瘤HEd 10的Fab片段[李，J.S.，刘易斯，J.R.，摩根，A.R.，莫斯曼，T.R.，&辛格，B.（1981年）《核酸研究》9，1707 - 1721]。结合数据通过荧光猝灭技术生成，结合常数[K(0)]从Scatchard图估算得出。Fab片段与聚（dT）紧密结合[K(0)=12.7×10(6) M-1]，对p(dT)2至p(dT)17系列的结合常数分析表明，识别序列由四个连续残基组成。离子强度对相互作用的影响表明仅涉及两个磷酸基团。聚（dU）、聚[d(brU)]、聚[d(brC)]和聚（rU）的结合常数分别为1.0×10(6) M-1、18.8×10(6) M-1、0.5×10(6) M-1和小于0.5×10(6) M-1，这表明嘧啶环的3、4和5位以及脱氧核糖在识别过程中起作用。在高离子强度（0.5 M）下，完整IgG与聚（dT）结合的K(0)为75×10(6) M-1，而Fab片段的值为1.1×10(6) M-1。这些结果可能对系统性红斑狼疮中含DNA免疫复合物引起的组织损伤有影响。
