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Updated: Jul 19, 2026
An Aptamer-based Sensor for Unchelated Gadolinium(III)
Published on: January 9, 2017
Spectral study on the binding of gadolinium ions with apoovotransferrin
Jin-Ling Wang1, Ying-Qi Li, Bin-Sheng Yang
1Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
Abstract:
The binding of Gd3+ ion to apoovotransferrin (apoOTf) was monitored by means of UV difference spectra in 0.01M Hepes, pH 7.4 at 25 degrees C. Used 2-p-toluidinylnaphthalene-6-sulfonate (TNS) as fluorescence probe the conformational changes of protein were studied while gadolinium ions bound to apoOTf. The results show that Gd3+ binding produces peaks at 244 and 294 nm that is the characteristic of binding at the apoOTf specific metal-binding sites. At 244 nm the molar absorptivity of Gd-apoOTf complex is (1.99+/-0.17)x10(4)cm(-1)M(-1). The apparent binding constants for the complexes of Gd3+ with apoovotransferrin are logK(1)=7.61+/-0.14 and logK(2)=4.96+/-0.26. A very large conformational change of apoovotransferrin appears when Gd3+ is bound to the N-terminal binding site. When Gd3+ is bound to C-terminal binding site there is less conformational change.
