A comparative study on binding ability of three lanthanide ions with centrin using impedance method

作者：Rong, Zhijiang; Tian, Yanni; Yang, Binsheng^*

来源：RSC Advances, 2014, 4(81): 43262-43269.

DOI：10.1039/c4ra08099h

• EUPLOTES-OCTOCARINATUS CENTRIN
• SELF-ASSEMBLED MONOLAYERS
• N-TERMINAL DOMAIN
• PROTEIN ADSORPTION
• STAINLESS-STEEL
• SOLID-SURFACES
• CROWN-ETHERS
• CALCIUM
• SPECTROSCOPY
• BEHAVIOR

Centrin, an EF-hand calcium-binding protein, is involved in the formation of the microtubule organizing center (MTOC). The interactions between Gd3+, Eu3+, La3+ and the N-terminal domain of ciliate Euplotes octocarinatus centrin (N-EoCen) were investigated by electrochemical impedance spectroscopy (EIS) using potassium ferricyanide as a redox probe. Results show that an increase in the lanthanide ion (Ln(3+)) concentration resulted in a lower impedance magnitude in the Nyquist plots when the N-EoCenmodified glassy carbon electrode (N-EoCen-GC) was used. The titrations of N-EoCen with Ln(3+) confirm the complexation reactivity of Ln(3+) with N-EoCen and suggest that the Ln(2)-N-EoCen complex was formed. In contrast, the binding ability of Ca2+ to N-EoCen is far less than that of Ln(3+). The binding constants of the metal ions to N-EoCen are in the order of Gd3+ approximate to Eu3+ >> La3+ Ca2+. Compared with the resonance light scattering (RLS) method, the EIS method can not only distinguish the binding ability of different metal ions to N-EoCen, but can also distinguish clearly the different metal ion binding sites on N-EoCen.

• 单位
  山西大学; 太原科技大学