In this communication, sulfate dodecyl sodium (SDS)-induced thermodynamics and conformational changes of collagen were studied. We used ultrasensitive differential scanning calorimetry (US-DSC) to directly monitor the thermal transition of collagen in the presence of SDS. The results show that SDS affects the conformation and thermal stability of collagen very differently depending on its concentrations. At CSDS ≤ 0.05 mM, the enhanced thermal stability of collagen indicates the stabilizing effect by SDS. However, a further increase of SDS leads to the denaturation of collagen, verifying the well-known ability of SDS to unfold proteins. This striking difference in thermodynamics and conformational changes of collagen caused by SDS concentrations can be explained in terms of their interactions. With increasing SDS, the binding of SDS to collagen can be dominated by electrostatic interaction shifting to hydrophobic interaction, and the latter plays a key role in loosening and unfolding the triple-helix structure of collagen. The important finding in the present study is the stabilizing effect of SDS on collagen molecules at extreme low concentration.

中文翻译：

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阴离子表面活性剂硫酸十二烷基钠 (SDS) 诱导胶原热力学和构象变化的超灵敏微量热法

在这次交流中，研究了硫酸十二烷基钠 (SDS) 诱导的热力学和胶原蛋白构象变化。我们使用超灵敏差示扫描量热法 (US-DSC) 直接监测存在 SDS 的胶原蛋白的热转变。结果表明，根据其浓度，SDS 对胶原的构象和热稳定性的影响非常不同。在 CSDS ≤ 0.05 mM 时，胶原蛋白的热稳定性增强表明 SDS 具有稳定作用。然而，SDS 的进一步增加会导致胶原蛋白变性，从而验证了众所周知的 SDS 展开蛋白质的能力。这种由 SDS 浓度引起的胶原热力学和构象变化的显着差异可以用它们的相互作用来解释。随着 SDS 的增加，SDS 与胶原蛋白的结合可以由静电相互作用转变为疏水相互作用主导，后者在胶原蛋白三螺旋结构的松散和展开中起关键作用。本研究的重要发现是 SDS 在极低浓度下对胶原分子的稳定作用。