物理化学学报 >> 2014, Vol. 30 >> Issue (1): 1-7.doi: 10.3866/PKU.WHXB201311263

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铜转运蛋白C端金属结合域与Ag+及Hg2+的相互作用

朱云城, 王二琼, 马国林, 康彦彪, 赵林泓, 刘扬中   

  1. 中国科学技术大学化学与材料科学学院, 苏州纳米科技协同创新中心, 合肥 230026
  • 收稿日期:2013-11-04 修回日期:2013-11-26 发布日期:2014-01-01
  • 通讯作者: 赵林泓,刘扬中 E-mail:lhzhao01@ustc.edu.cn;liuyz@ustc.edu.cn
  • 基金资助:

    国家自然科学基金(U1332210,21171156)及博士后基金(2013M541831)资助项目

Interaction of C-Terminal Metal-Binding Domain of Copper Transport Protein with Ag+ and Hg2+

ZHU Yun-Cheng, WANG Er-Qiong, MA Guo-Lin, KANG Yan-Biao, ZHAO Lin-Hong, LIU Yang-Zhong   

  1. Collaborative Innovation Center of Suzhou Nano Science and Technology, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2013-11-04 Revised:2013-11-26 Published:2014-01-01
  • Contact: ZHAO Lin-Hong, LIU Yang-Zhong E-mail:lhzhao01@ustc.edu.cn;liuyz@ustc.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (U1332210, 21171156) and Postdoctoral Science Foundation of China (2013M541831).

摘要:

铜转运蛋白(CTR1)不仅参与铜的细胞摄取,而且在其它重金属离子的摄取过程中也发挥重要作用. 本文采用紫外-可见(UV-Vis)光谱,核磁共振(NMR)和质谱(MS)的方法,研究了人源CTR1 (hCTR1)的C端金属结合域(C8)与Ag+和Hg2+的相互作用. 研究表明,Ag+和Hg2+都能与C8结合,但二者与C8的结合机制明显不同. 每个C8分子可以结合两个Ag+离子,但一个Hg2+却可以与两个C8形成桥联. 此外,Ag+离子与C8的配位是一个中等速度的交换过程,而Hg2+离子则为快速交换过程. C8的半胱氨酸残基是两种离子的重要结合位点,同时组氨酸残基也参与两种金属离子的配位,其中Ag+优先结合组氨酸,而Hg2+则对半胱氨酸的结合具有显著的优势. 虽然HCH基序对C8 与金属配位至关重要,一些远端的其它氨基酸也可以参与C8 与银离子的配位,这可能与CTR1 在摄取Ag+过程中的金属转移机制相关. 这些结果为理解hCTR1 蛋白摄取重金属离子的作用机制提供了必要的信息.

关键词: 铜转运蛋白, 银离子, 汞离子, 结合模式, 核磁共振, 质谱

Abstract:

Copper transport protein (CTR1), which is essential for copper uptake, also plays an important role in the cellular uptake of other heavy metal ions. In this work, the interactions of the C-terminal metalbinding domain of human CTR1 (C8) with both Ag+ and Hg2+ were studied, using ultraviolet-visible (UV-Vis) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS). The results showed that Ag+ and Hg2+ bind to C8 by different binding modes. Each C8 binds to two Ag+, whereas one Hg2+ crosslinks two C8 units. In addition, the coordination of Ag+ to C8 has an intermediate exchange rate, whereas the binding of Hg2+ to C8 has a fast exchange rate. The cysteine residue of C8 is one of the most important binding sites for both Ag+ and Hg2+. However, histidine residues are also involved in the metalbinding process. Ag+ binds histidine preferentially, whereas Hg2+ prefers to bind to cysteine residues. Although the HCH motif of C8 is crucial for metal binding, some other residues can also participate in the binding of Ag+. These residues may be involved in the metal-transfer process in the cellular uptake of Ag+ by CTR1. These results provide important information for a better understanding of the mechanism of cellular uptake of metal ions by CTR1.

Key words: Copper transport protein, Ag+, Hg2+, Binding mode, Nuclear magnetic resonance, Mass spectrometry

MSC2000: 

  • O641