红外光谱研究氧化石墨烯诱导的葡萄糖氧化酶构象变化,Colloids and Surfaces B: Biointerfaces

蛋白质在纳米材料表面上的吸附可以诱导蛋白质的结构和生物学活性发生变化。尽管已经进行了许多研究，旨在加深对蛋白质与纳米材料表面相互作用的理解，但尚未报道对吸附蛋白质的实际状态或蛋白质吸附到纳米材料上的功能后果的详细描述。在这项研究中，通过定量二阶导数红外分析和二维红外相关光谱法（2D IR）研究了氧化石墨烯（GO）片上吸附引起的葡萄糖氧化酶（GOx）的构象变化。GOx在GO片材上的吸附导致α-螺旋转化为β-表层结构，因此导致GOx的基本构象变化，甚至蛋白质的展开。GOx构象的这些改变导致酶对葡萄糖氧化的催化活性显着降低。这项研究表明，纳米材料可以强烈影响吸附蛋白的构象和活性。除了在蛋白质直接吸附在纳米材料上的情况下这种效果的重要性外，该结果对于蛋白质吸附在具有纳米级表面粗糙度的材料上也有影响。

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The adsorption of proteins on the surface of nanomaterials can induce changes in the structure and biological activity of the proteins. Although there have been a number of studies aimed at developing an understanding of the interactions of proteins with surfaces of nanomaterials, a detailed description of the actual state of the adsorbed proteins or the functional consequences of protein adsorption onto nanomaterials has yet to be reported. In this study, the conformation changes of glucose oxidase (GOx) induced by adsorption on graphene oxide (GO) sheets were investigated by quantitative second-derivative infrared analysis and two-dimensional infrared correlation spectroscopy (2D IR). The adsorption of GOx on GO sheets resulted in the conversion of α-helix to β-sheet structures and therefore led to substantial conformation changes of GOx, even the unfolding of the protein. These alterations in the conformation of GOx caused a significant decrease in the catalytic activity of the enzyme for glucose oxidation. This study demonstrates that nanomaterials can strongly influence the conformation and activity of adsorbed proteins. In addition to the importance of this effect in cases of the direct adsorption of proteins on nanomaterials, the results have implications for proteins adsorbed on materials with nanometer-scale surface roughness.