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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (10): 1027-1031. 上一篇    下一篇

研究论文

铕(III)对伴清蛋白溶液构象的影响

李英奇*,1,2，周雪萍2，任学英1，段新娥1   

  1. (1山西大学化学化工学院 太原 030006)
    (2山西大学分子科学研究所 化学生物学与分子工程教育部重点实验室 太原 030006)
  • 投稿日期:2009-06-29 修回日期:2009-11-06 发布日期:2010-01-06
  • 通讯作者: 李英奇 E-mail:wkyqli@sxu.edu.cn

Effect of Eu3＋ on the Conformation of Apoovotransferrin

Li Yingqi*,1,2 Zhou Xueping2 Ren Xueying1 Duan Xine1   

  1. (1 Department of Chemistry, College of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006)
    (2 Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan 030006)
  • Received:2009-06-29 Revised:2009-11-06 Published:2010-01-06
  • Contact: LI-Ying-Qi E-mail:wkyqli@sxu.edu.cn

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被引次数

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用TNS疏水探针研究了脱铁伴清蛋白(apoOTf)和不同形式的铕伴清蛋白(EuN-OTf, Eu2-OTf)的表面疏水暴露程度, 依次为apoOTf＞EuN-OTf＞Eu2-OTf, 表明Eu3＋与脱铁伴清蛋白N端结合引起蛋白构象变化大, 与C端结合引起蛋白构象变化小. 此外, 由盐酸胍对3种蛋白变性实验, 发现Eu3＋与脱铁伴清蛋白的结合稳定了蛋白的结构, 稳定性依次为apoOTf＜EuN-OTf＜Eu2-OTf. 离子强度效应也充分表明3种蛋白内部疏水基团相互作用依apoOTf＜EuN-OTf＜Eu2-OTf顺序增大, 稳定性也依次增大. 本研究对进一步探讨Eu3＋的生物效应提供理论依据.

关键词: 伴清蛋白, Eu3＋, 构象变化

The extent of exposed hydrophobic patch on apoovotransferrin (apoOTf) and various species of europium(III) ovotransferrin (EuN-OTf and Eu2-OTf) were investigated using 2-p-toluidinylnaphthalene-6-sulfonate (TNS) as a fluorescence probe. The result showed that the extent of exposed hydrophobic patch on the protein was in turn: apoOTf＞EuN-OTf＞Eu2-OTf. And apoovotransferrin (apoOTf) undergoes a large conformational change when Eu3＋ binds to the N-terminal site, but a small conformational change when the ion binds to the C-terminal site. In addition, the guanidine hydrochloride denaturation experiments on three kinds of protein showed that the binding of Eu3+ to apoOTf led to a stable structure of OTf. Stability is in turn apoOTf＜EuN-OTf＜Eu2-OTf. Ion strength effects demonstrate that internal hydrophobic interactions were enhanced in accordance with Eu2-OTf＞EuN-OTf＞apoOTf, thus stabilizing the protein conformation accordingly. Such information may afford our understanding of the biological effect on rare earth.

Key words: apoovotransferrin, Eu3＋, conformational change