Cobine P, Wickramasinghe W A, Harrison M D, Weber T, Solioz M, Dameron C T
National Research Centre for Environmental Toxicology, University of Queensland, Coopers Plains, Australia.
FEBS Lett. 1999 Feb 19;445(1):27-30. doi: 10.1016/s0014-5793(99)00091-5.
Expression of the cop operon which effects copper homeostasis in Enterococcus hirae is controlled by the copper responsive repressor CopY. Purified Zn(II)CopY binds to a synthetic cop promoter fragment in vitro. Here we show that the 8 kDa protein CopZ acts as a copper chaperone by specifically delivering copper(I) to Zn(II)CopY and releasing CopY from the DNA. As shown by gel filtration and luminescence spectroscopy, two copper(I) are thereby quantitatively transferred from Cu(I)CopZ to Zn(II)CopY, with displacement of the zinc(II) and transfer of copper from a non-luminescent, exposed, binding site in CopZ to a luminescent, solvent shielded, binding site in CopY.
在平肠球菌中影响铜稳态的cop操纵子的表达受铜响应阻遏物CopY的控制。纯化的Zn（II）CopY在体外与合成的cop启动子片段结合。在此我们表明，8 kDa的蛋白质CopZ作为铜伴侣蛋白，通过将铜（I）特异性递送至Zn（II）CopY并使CopY从DNA上释放。如凝胶过滤和发光光谱所示，两个铜（I）由此从Cu（I）CopZ定量转移至Zn（II）CopY，锌（II）被置换，并且铜从CopZ中一个非发光的、暴露的结合位点转移至CopY中一个发光的、溶剂屏蔽的结合位点。
