Sodium Hexadecyl Sulfate as an Interfacial Substance Adjusting the Adsorption of a Protein on Carbon Nanotubes
Sodium Hexadecyl Sulfate as an Interfacial Substance Adjusting the Adsorption of a Protein on Carbon Nanotubes
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十六烷基硫酸钠作为界面物质调节碳纳米管上蛋白质的吸附
DOI：
10.1021/am5032715
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发表时间：
2014
影响因子：
9.5
通讯作者：
Ji Peijun
中科院分区：
文献类型：
--
作者：
Sun Jian;Du Kun;Fu Li;Gao Jiang;Zhang Haiyang;Feng Wei;Ji Peijun
采用十六烷基硫酸钠（SHS）对碳纳米管（CNTs）进行功能化。吸附在SHS碳纳米管上的溶菌酶比固定在非功能化碳纳米管上的溶菌酶具有更高的活性。为了解释实验结果并探讨溶菌酶吸附机理，对溶菌酶、SHS、CNTs在显式水中的四组分体系进行了大尺度分子动力学模拟。研究发现，自蔓延高温合成分子在碳纳米管表面形成了一层柔软的膜层。溶菌酶与SHS之间的相互作用诱导SHS分子重排，在CNT表面形成鞍状结构。这种鞍状结构与溶菌酶的形状相吻合，并且溶菌酶的活性位点裂缝暴露于水相。然而，对于吸附在非功能化的CNT上的溶菌酶，由于疏水相互作用，酶的活性位点裂缝倾向于面向CNT的壁。研究结果表明，SHS分子作为界面物质，对溶菌酶具有一定的定向调节作用，有利于提高溶菌酶的活性。
Carbon nanotubes (CNTs) were functionalized with sodium hexadecyl sulfate (SHS). The lysozyme adsorbed on the SHS-CNTs exhibited a higher activity than that immobilized on the nonfunctionalized CNTs. To explain the experimental results and explore the mechanism of lysozyme adsorption, large-scale molecular dynamics simulations have been performed for a four-component system, including lysozyme, SHS, CNTs in explicit water. It has been found that the assembled SHS molecules form a soft layer on the surface of CNTs. The interactions between lysozyme and SHS induce the rearrangement of SHS molecules, forming a saddle-like structure on the CNT surface. The saddle-like structure fits the shape of the lysozyme, and the active-site cleft of the lysozyme is exposed to the water phase. Whereas, for the lysozyme adsorbed on the nonfunctionalized CNT, due to the hydrophobic interactions, the active-site cleft of the enzyme tends to face the wall of the CNT. The results of this work demonstrate that the SHS molecules as the interfacial substance have a function of adjusting the lysozyme with an appropriate orientation, which is favorable for the lysozyme having a higher activity.