Structure-function relationships of domains of the delta subunit in Escherichia coli adenosine triphosphatase.
Structure-function relationships of domains of the delta subunit in Escherichia coli adenosine triphosphatase.
复制标题
大肠杆菌腺苷三磷酸酶δ亚基结构域的结构-功能关系。
DOI：
10.1016/s0005-2728(05)80126-4
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Capaldi,RA
中科院分区：
文献类型：
--
作者：
Mendel-Hartvig,J;Capaldi,RA
已经通过蛋白酶消化和化学标记方法探索了大肠杆菌腺苷三磷酸酶(ECF1)和亚基的拓扑结构。 ECF1 的 δ 亚基可以通过酶复合物与极少量胰蛋白酶（1:5000，w/w）的反应被选择性切割。 δ 亚基的裂解从 C 末端连续发生。通过蔗糖梯度离心，δ亚基的N端片段仍然与核心ECF1复合物结合，表明该亚基的部分结合涉及N端片段。 ECF1（其中约 20 个氨基酸已从 δ 的 C 末端去除）仍与 ECF0 结合，但 ATP 酶活性的 DCCD 敏感性丧失。当ECF1与天然状态的N-乙基[14C]马来酰亚胺([14C]NEM)反应时，δ亚基上仅两个Cys残基之一被修饰。该残基 Cys-140 也在 ECF1F0 中进行了标记。 Cys-140 显示参与 α 和 δ 亚基之间的二硫键，该二硫键是用 CuCl2 处理 ECF1 时生成的。因此，Cys-140 周围 δ 亚基的 C 端部分可以与核心 ECF1 复合物相互作用。这些结果提出了 δ 亚基的模型，其中多肽的中心部分是茎的一部分，N 端和 C 端均与 ECF1 相关。
The topology of the and subunit of theEscherichia coliadenosinetriphosphatase (ECF1) has been explored by proteinase digestion and chemical labeling methods. The δ subunit of ECF1could be cleaved selectively by reaction of the enzyme complex with very low amounts of trypsin (1:5000, w/w). Cleavage of the δ subunit occurred serially from the C-terminus. The N-terminal fragments of the δ subunit remained bound to the core ECF1complex through sucrose gradient centrifugation, indicating that part of the binding of this subunit involves the N-terminal segment. ECF1, in which around 20 amino acids had been removed from the C-terminus of δ, still bound to ECF0but DCCD sensitivity of the ATPase activity was lost. When ECF1was reacted withN-ethyl[14C]maleimide ([14C]NEM) in the native state, only one of the two Cys residues on the δ subunit was modified. This residue, Cys-140, was also labeled in ECF1F0. Cys-140 was shown to be involved in the disulfide bridge between α and δ subunits that is generated when ECF1is treated with CuCl2. Thus, the C-terminal part of the δ subunit around Cys-140 can interact with the core ECF1complex. These results suggest a model for the δ subunit in which the central part of polypeptide is a part of the stalk, with both N- and C-termini associated with ECF1.