Slattery J, Holowka D, Baird B
Biochemistry. 1985 Dec 17;24(26):7810-20. doi: 10.1021/bi00347a046.
The segmental flexibility of mouse immunoglobulin E (IgE) bound to its high-affinity receptor on membrane vesicles from rat basophilic leukemia cells was compared to that of IgE in solution by measuring the steady-state anisotropy as a function of temperature and viscosity. A monoclonal IgE was used to bind the fluorescent probe N-[5-(dimethylamino)naphthalene-1-sulfonyl]-L-lysine (DNS-Lys) rigidly and specifically in the antigen combining site at the tip of the Fab region. The average rotational correlation time, phi, of 74-89 ns for the receptor-bound IgE is only slightly longer than that for IgE in solution where phi = 54 ns. Another mouse monoclonal IgE was covalently labeled in the Fab region with N-(1-pyrenyl)maleimide. Anisotropy measurements with this derivative yielded results that are very similar to those found with anti-DNS IgE and DNS-Lys. These findings are strikingly different from that expected for a rigid IgE bound to its receptor since in this case phi is likely to be very much larger. Evidently, the segmental flexibility of IgE is not greatly altered upon binding to its receptor.
通过测量稳态各向异性随温度和粘度的变化，比较了与大鼠嗜碱性白血病细胞膜囊泡上高亲和力受体结合的小鼠免疫球蛋白E（IgE）的片段柔韧性与溶液中IgE的片段柔韧性。使用一种单克隆IgE将荧光探针N-[5-（二甲基氨基）萘-1-磺酰基]-L-赖氨酸（DNS-Lys）牢固且特异性地结合在Fab区域末端的抗原结合位点。与受体结合的IgE的平均旋转相关时间φ为74 - 89纳秒，仅略长于溶液中IgE的平均旋转相关时间（φ = 54纳秒）。另一种小鼠单克隆IgE在Fab区域用N-（1-芘基）马来酰亚胺进行共价标记。用这种衍生物进行的各向异性测量结果与用抗DNS IgE和DNS-Lys得到的结果非常相似。这些发现与预期的与受体结合的刚性IgE的情况显著不同，因为在这种情况下φ可能会大得多。显然，IgE与受体结合后其片段柔韧性没有太大改变。
