| 摘要: |
| 用大肠杆菌表达含有GST标签的基质蛋白KRMP-3。利用圆二色谱(Circular Dichroism, CD)研究不同浓度钙离子和镁离子对基质蛋白KRMP-3二级结构的影响。结果表明,钙离子对其二级结构的变化远大于镁离子;同时,采用荧光淬灭法研究KRMP-3 对钙, 镁, 锶, 钡等二价金属离子的选择性,结果表明,KRMP-3对钙离子有特异性选择性,钙离子与KRMP-3的结合常数K约为103L/mol,结合位点数n近似为1,表明KRMP-3与钙离子的结合能力适中,推测基质蛋白KRMP-3对合浦珠母贝(Pinctada fucata)棱柱层形成起到促进作用。 |
| 关键词: 生物矿化 基质蛋白KRMP-3 圆二色谱CD 荧光淬灭法 离子选择性 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目(U0831001) |
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| Ionic selectivity of KRMP-3, a shell matrix protein of Pinctada fucata |
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| Abstract: |
| KRMP-3 with GST-tag is expressed in Escherichia coli. Using Circular dichroism (CD), we have studies the changes of KRMP-3 secondary structure with concentrations of calcium and magnesium ions, and we found that calcium ion has much stronger effect than magnesium ions. Moreover, we also studied ionic selectivity of KRMP-3 using fluorescence quenching method with Ca2+, Mg2+, Sr2+ and Ba2+, and we found that KRMP-3 has very high selectivity towards calcium ion. The static quenching constant K=103L/mol and the binding sites number n=1, suggesting KRMP-3 has a moderate binding capacity with calcium ion. We speculate KRMP-3 could promote the formation of the Pinctada fucata prismatic layer. |
| Key words: Biomineralization matrix protein KRMP-3, Circular dichroism fluorescence quenching ionic selectivity |
