Urea Disrupts the AOT Reverse Micelle Structure at Low Temperatures
Urea Disrupts the AOT Reverse Micelle Structure at Low Temperatures
复制标题
尿素在低温下破坏 AOT 反胶束结构
DOI：
10.1021/acs.langmuir.2c00206
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发表时间：
2022
期刊：
影响因子：
3.9
通讯作者：
Levinger, Nancy E.
中科院分区：
文献类型：
--
作者：
Miller, Samantha L.;Levinger, Nancy E.
除了在排泄系统中的重要作用外，尿素也是一种已知的蛋白质变性剂。在这里，我们将尿素在AOT(双(2-乙基己基)琥珀酸磺酸钠)反胶束的受限空间中的行为描述为在亚细胞水平上发现的紧密的受限空间的模型。动态光散射显示，低温(275K)导致最小的反胶束尺寸(W0=10)不稳定，表观流体力学直径显著增加。2D1H-NOESY核磁共振谱证实，这是由于尿素嵌入了表面活性剂界面。通过1D EXSY-核磁共振的测量，这种尺寸的增加反过来导致了纳米反胶束中尿素和水之间的氢交换增加。在0=15或20的反胶束中，尿素水溶液的放大效应很小，氢交换没有增加，这表明这种效应是特别小直径空间(∼7 nm)所特有的。
Aside from its prominent role in the excretory system, urea is also a known protein denaturant. Here, we characterize urea as it behaves in confined spaces of AOT (sodium bis(2-ethylhexyl) sulfosuccinate) reverse micelles as a model of tight, confined spaces found at the subcellular level. Dynamic light scattering revealed that low temperatures (275 K) caused the smallest of the reverse micelle sizes,w0= 10, to destabilize and dramatically increase in apparent hydrodynamic diameter. We attribute this to urea embedded into the surfactant interface as confirmed by 2D1H-NOESY NMR spectroscopy. This increase in size in turn caused the hydrogen exchange between urea and water within the nanosized reverse micelles to increase as measured by 1D EXSY-NMR. A minimal enlarging effect and no increase in hydrogen exchange were observed when aqueous urea was introduced intow0= 15 or 20 reverse micelles, suggesting that this effect is unique to particularly small-diameter spaces (∼7 nm).