Spectroscopic analysis of the interaction between chromium (III) and apoovotransferrin

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• 作者：Yingqi Li ; Bin Liu ; Binsheng Yang
• 关键词：Apoovotransferrin ; Cr³⁺ ; Spectra ; Conformation change
• 刊名：Journal of Luminescence
• 出版年：2010
• 出版时间：December 2010
• 年：2010
• 卷：130
• 期：12
• 页码：2339-2345
• 全文大小：322 K

文摘

Ovotransferrin (OTf) is a main member of the transferrin family that functions both as an iron transporter and an antibacterial agent. In this study, the thermodynamic property of the interaction between chromium (III) and ovotransferrin was investigated. The conditional binding constants for Cr³⁺ binding to the protein were determined by difference UV spectroscopy and were found to be log K_C=13.08±0.24 and log K_N=5.65±0.12. It was found that Cr³⁺ preferentially binds to the C-terminal site over the N-terminal site under these experimental conditions. The conformational changes in apoovotransferrin (apoOTf) during Cr³⁺ binding were studied by fluorescence spectroscopy using 2-p-toluidinylnaphthalene-6-sulfonate (TNS) as the fluorescence probe and by circular dichroism (CD) spectroscopy. The results show that a large conformational change in apoOTf can be attributed to binding of Cr³⁺ to the N-terminal site, instead of the C-terminal site. In addition, the binding of Cr³⁺ to apoOTf stabilizes the structure of OTf as determined by guanidine hydrochloride denaturation studies. These findings help advance our understanding of the biological effects of Cr³⁺.