磷酸胆碱与特定小鼠骨髓瘤免疫球蛋白之间结合位点相互作用的磁共振研究。

Magnetic resonance studies of the binding site interactions between phosphorylcholine and specific mouse myeloma immunoglobulin.

作者信息

Goetze A M, Richards J H

出版信息

Biochemistry. 1977 Jan 25;16(2):228-32. doi: 10.1021/bi00621a011.

Abstract

The interaction of phosphorycholine-binding mouse myeloma protein M603 and the isotopically substituted hapten phosphoryl[methyl-13C] choline has been investigated using 13C and 31P nuclear magnetic resonance (NMR) spectroscopy. Upon binding to antibody, upfield shifts of 0.7 and 1.5 ppm are observed for the hapten 13C and 31P resonances, respectively, and both spectra are in the "slow" exchange limit. Linewidth analysis indicates some immobilization of the phosphate group but essentially unrestricted methyl group rotation for the bound hapten. Hapten-antibody dissociation rate constants of 10 and 38 s-1 are calculated from 13C and 31P NMR spectra, respectively, suggesting the possibility of differential dissociation rates for the two opposing ends of the phosphorylcholine molecule. The NMR data are entirely consistent with the known x-ray structure of the M603 Fab'-phosporylcholine complex (Segal,D.M., Padlan, E.A., Cohen G.H., Rudikoff S., Potter,M., and Davies, D.R. (1974), Proc. Natl. Acad. Sci. U.S.A. 71, 4298).

摘要

利用碳-13（13C）和磷-31（31P）核磁共振（NMR）光谱，研究了磷酸胆碱结合型小鼠骨髓瘤蛋白M603与同位素取代的半抗原磷酸化[甲基-13C]胆碱之间的相互作用。与抗体结合后，半抗原的13C和31P共振峰分别出现了0.7 ppm和1.5 ppm的上移，并且两个光谱均处于“慢”交换极限。线宽分析表明，磷酸基团有一定程度的固定，但结合的半抗原的甲基旋转基本不受限制。分别从13C和31P NMR光谱计算出半抗原-抗体解离速率常数为10 s-1和38 s-1，这表明磷酸胆碱分子的两个相对末端可能存在不同的解离速率。NMR数据与已知的M603 Fab'-磷酸胆碱复合物的X射线结构完全一致（Segal, D.M., Padlan, E.A., Cohen G.H., Rudikoff S., Potter, M., and Davies, D.R. (1974), Proc. Natl. Acad. Sci. U.S.A. 71, 4298）。