Interaction of fibronectin with C1q and collagen. Effects of ionic strength and denaturation of the collagenous component.
Interaction of fibronectin with C1q and collagen. Effects of ionic strength and denaturation of the collagenous component.
复制标题
纤连蛋白与 C1q 和胶原蛋白的相互作用。
DOI：
10.1111/j.1432-1033.1985.tb08828.x
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Engel,J
中科院分区：
文献类型：
--
作者：
Ingham,KC;Landwehr,R;Engel,J
通过将天然胶原和C1q附着到Sepharose上，可以测试纤维连接蛋白(FN)与这些蛋白质的天然和热变性形式的结合，而不会因聚集、沉淀或纤维形成而出现并发症。与天然蛋白质的结合仅在低离子强度(亚生理)时发生，而与变性蛋白质的结合即使在1M的氯化钠中也发生。因此，这两种蛋白质都有一个或多个在天然状态下被遮蔽并在热变性过程中暴露出来的强位点。FN在热变性前后均不与白蛋白-琼脂糖凝胶或免疫球蛋白-琼脂糖凝胶结合。C1q很容易与天然的Ig G-Sephose结合，但不介导Fn的结合。FN也不抑制抗体包被的红细胞上C1的重组。荧光素标记的胶原在1M氯化钠溶液中的荧光偏振度在38~40°C出现向下跃迁，与三螺旋结构的展开一致。在FN的存在下，相同的材料在略低的温度下显示出向上的转变，这表明不需要总的展开来暴露强结合部位(S)。
By attaching native collagen and C1q to Sepharose, it was possible to test the binding of fibronectin (Fn) to the native and heat‐denatured forms of these proteins without complications due to aggregation, precipitation, or fibril formation. Binding to the native proteins occurred only at low (sub‐physiological) ionic strength whereas binding to the denatured proteins occurred even in 1 M NaCl. Thus both of these proteins possess one or more strong sites which are masked in the native state and become exposed during thermal denaturation. Fn did not bind to albumin‐Sepharose or IgG‐Sepharose either before or after heat‐denaturation. C1q bound readily to native IgG‐Sepharose but did not mediate the binding of Fn. Nor did Fn inhibit the reconstitution of C1 on antibody‐coated erythrocytes. The fluorescence polarization of fluorescein‐labeled collagen in 1 M NaCl displayed a downward transition at 38–40°C consistent with unfolding of the triple helix. In the presence of Fn, the same material displayed an upward transition at slightly lower temperature suggesting that gross unfolding is not required to expose the strong binding site(s).