Evidence for a protein-protein complex during iron loading into ferritin by ceruloplasmin.
Evidence for a protein-protein complex during iron loading into ferritin by ceruloplasmin.
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铜蓝蛋白将铁加载到铁蛋白过程中存在蛋白质-蛋白质复合物的证据。
DOI：
10.1006/abbi.1998.0672
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Aust,SD
中科院分区：
文献类型：
--
作者：
Reilly,CA;Sorlie,M;Aust,SD
研究了铜蓝蛋白负载铁蛋白的蛋白质-蛋白质复合体的形成。铁蛋白能刺激铜蓝蛋白的铁氧合酶活性，除非铁蛋白被完全负载，否则铁蛋白会抑制铜蓝蛋白的铁氧合酶活性。铁蛋白与铜蓝蛋白相互作用的表观结合常数为24 nm。等温滴定量热法表明，铜蓝蛋白与铁蛋白的相互作用是吸热的，受正向熵的驱动。还原形式和氧化形式的铜蓝蛋白与铁蛋白形成络合物的结合常数分别为4.5±0.7×10 5和9.5±0.3×10 4M−1。氧化形式的铜蓝蛋白保留在以铁蛋白为配基的亲和层析柱上，并通过疏水性增加的流动相结合在柱上，但随着离子强度的增加而洗脱。铜蓝蛋白与亲和树脂结合的能力受分离铜蓝蛋白的种类的影响。梯度超速离心法也提供了两种蛋白相互关联的证据，因为铁蛋白促进了铜蓝蛋白通过梯度的迁移。在梯度中加入亚铁导致铜蓝蛋白的还原，并增加铜蓝蛋白与铁蛋白的迁移率。这些数据提供了铁蛋白和铜蓝蛋白在铁负载到铁蛋白过程中形成蛋白质-蛋白质复合体的证据，这可能限制铁蛋白在体内的氧化还原循环。
The formation of a protein–protein complex for the loading of iron into ferritin by ceruloplasmin was investigated. Ferritin stimulated the ferroxidase activity of ceruloplasmin unless the ferritin was fully loaded, in which case it inhibited the ferroxidase activity of ceruloplasmin. The apparent association constant for the interaction of ferritin and ceruloplasmin was 24 nM. Isothermal titration calorimetry indicated that the interaction of ceruloplasmin and ferritin was endothermic, driven by positive changes in entropy. The association constants for complex formation between ferritin and ceruloplasmin were 4.5 ± 0.7 × 105and 9.5 ± 0.3 × 104M−1for the reduced and oxidized forms of ceruloplasmin, respectively. The oxidized form of ceruloplasmin was retained on an affinity column with ferritin immobilized as the ligand and remained bound to the column with mobile phases of increased hydrophobicity, but was eluted with increased ionic strength. The ability of ceruloplasmin to remain bound to the affinity resin was affected by the species from which ceruloplasmin was isolated. Gradient ultracentrifugation also provided evidence that the two proteins were associated, since ferritin promoted migration of ceruloplasmin through the gradient. Including ferrous iron in the gradient resulted in reduction of ceruloplasmin and increased the mobility of ceruloplasmin with ferritin. These data provide evidence that ferritin and ceruloplasmin form a protein–protein complex during iron loading into ferritin, which may limit redox cycling of ironin vivo.
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影响因子：
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作者：
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影响因子：
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DOI：
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发表时间：
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影响因子：
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DOI：
--
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