COOPERATIVE CLUSTER FORMATION IN METALLOTHIONEIN
COOPERATIVE CLUSTER FORMATION IN METALLOTHIONEIN
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DOI：
10.1016/0003-9861(86)90721-6
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发表时间：
1986-10-01
影响因子：
3.9
通讯作者：
WINGE, DR
中科院分区：
文献类型：
--
作者：
BYRD, J;WINGE, DR
在研究金属硫酸盐簇形成过程中，采用离子交换色谱法从金属形态中分离出载金属硫蛋白。在中性pH下，用Cd（II）、Zn（II）或Cu(I)在羧甲基纤维素上进行金属硫蛋白重组的层析，可以从溶液中去除载脂蛋白，但对金属蛋白的回收没有影响。对流出物的分析显示，这些金属离子明显地与蛋白质协同结合。加入1-4 mol eq的Cd（II）离子后，金属硫蛋白以约4 mol eq的Cd结合恢复。该形式的产率随起始金属离子当量的增加而增加。这些结果是用两种不同的离子交换树脂得到的。结合的协同性不是完全的，但最初仅限于羧基末端。域。金属和蛋白质产率的结果与随机、非相互作用结合不一致。在Zn（II）和Cu(I)离子中也得到了类似的数据，尽管Cu(I)在氨基末端表现出最初的协同结合。Cu(I)键大于5 mol eq的区域。
An ion-exchange chromatography procedure was used to resolve apometallothionein from the metallo-form in a study of metal-thiolate cluster formation. Chromatography of metallothionein reconstituted with Cd(II), Zn(II), or Cu(I) at neutral pH on carboxymethyl-cellulose led to removal of apoprotein from a solution without effect on recovery of the metalloprotein. Analysis of the effluent revealed apparent cooperative binding of these metal ions to the protein. Addition of 1-4 mol eq Cd(II) ions led to the recovery of metallothionein with around 4 mol eq Cd bound. The yield of this form increased with increasing starting metal ion equivalency. These results were obtained with two different ion-exchange resins. The cooperativity of binding was not total, but was initially confined to the carboxyl-terminal .alpha. domain. The results of metal and protein yields are inconsistent with random, noninteractive binding. Similar data were obtained with Zn(II) and Cu(I) ions although Cu(I) exhibited initial cooperative binding within the aminoterminal .beta. domain with over 5 mol eq Cu(I) bound.