Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (1): 1-7.doi: 10.3866/PKU.WHXB201311263

• COMMUNICATION • Previous Articles     Next Articles

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).

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