Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50383, Wroclaw, Poland.
Dalton Trans. 2011 May 28;40(20):5604-10. doi: 10.1039/c1dt10187k. Epub 2011 Apr 18.
The Hpn and HspA proteins from H. pylori are significant for nickel homeostasis and protect the cells from higher concentrations of external metal ions. Both proteins have a unique histidine- and cysteine-rich domain at the C terminus. The interactions of Ni(2+), Bi(3+), Zn(2+) and Cd(2+) ions with C-terminal Ac-CCSTSDSHHQ-NH(2) and Ac-EEGCCHGHHE-NH(2) fragments from Hpn and the Ac-GSCCHTGNHD-NH(2) sequence from HspA were studied by potentiometry, mass spectrometry, circular dichroism and UV-Vis spectroscopy. Ac-CC-NH(2) was used as a reference peptide. The studies have shown that nickel ions form planar complexes with a {2S(-),N(-)} binding mode. The thiol sulfurs of the -Cys-Cys- motif are also the anchoring sites for Bi(3+), Zn(2+) and Cd(2+) ions. The studied protein fragments have the highest affinity for Bi(3+) ions. The thermodynamic stability of Ni(2+) is much higher then that of Zn(2+).
幽门螺杆菌的 Hpn 和 HspA 蛋白对于镍的体内平衡很重要，并且可以保护细胞免受高浓度的外部金属离子的侵害。这两种蛋白的 C 端都有一个独特的富含组氨酸和半胱氨酸的结构域。通过电位法、质谱法、圆二色性和紫外可见光谱法研究了 Ni(2+)、Bi(3+)、Zn(2+)和 Cd(2+)离子与 Hpn 的 C 端 Ac-CCSTSDSHHQ-NH(2)和 Ac-EEGCCHGHHE-NH(2)片段以及 HspA 的 Ac-GSCCHTGNHD-NH(2)序列的相互作用。Ac-CC-NH(2) 被用作参考肽。研究表明，镍离子与 {2S(-),N(-)} 结合模式形成平面配合物。-Cys-Cys- 基序的硫醇硫也是 Bi(3+)、Zn(2+)和 Cd(2+)离子的锚定位点。所研究的蛋白片段对 Bi(3+)离子具有最高的亲和力。Ni(2+)的热力学稳定性远高于 Zn(2+)。
