Oxidative stress is a physiological condition where oxygen radicals are responsible for the conformational restructuring and loss of functionality of important biomacromolecules. Among the various external agents, UV irradiation is one of the sources that can induce oxidative stress. Here, we report an in vitro study to gauge the effect of ROS on the structural rearrangement of hen egg white lysozyme, a hydrolytic enzyme, via UVC exposure studied via various biophysical techniques. The investigations revealed a rise in the β-sheet content of the protein at the expense of a decrease in α-helix within ten minutes of exposure, thereby showing rapid changes in the secondary structure. While the unexposed sample showed partial reversibility after being subjected to a heating and cooling cycle, the newly formed structures via irradiation, on the other hand, were found to be more thermally stable. The aging of the samples via UVC exposure was reflected in both the UV-vis and PL spectra of the samples, as well as the loss of spectral features in the aliphatic and aromatic regions in the magnetic resonance spectrum. Finally, the increase in the hydrodynamic diameter of the samples shows cross-linking taking place due to the generated oxygen radicals.

中文翻译：

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UVC 照射对蛋清溶菌酶结构重排的氧化应激


氧化应激是一种生理状况，其中氧自由基负责重要生物大分子的构象重组和功能丧失。在各种外部因素中，紫外线照射是可诱导氧化应激的来源之一。在这里，我们报告了一项体外研究，通过各种生物物理技术研究的 UVC 暴露来衡量 ROS 对蛋清溶菌酶（一种水解酶）结构重排的影响。研究显示，蛋白质的 β 页含量增加，而暴露后 10 分钟内 α 螺旋含量减少，从而显示二级结构的快速变化。虽然未曝光的样品在经过加热和冷却循环后显示出部分可逆性，但另一方面，通过辐照新形成的结构被发现具有更高的热稳定性。样品因 UVC 暴露而老化的情况反映在样品的 UV-VIS 和 PL 光谱中，以及磁共振光谱中脂肪族和芳香族区域的光谱特征损失。最后，样品流体动力学直径的增加表明，由于产生的氧自由基而发生了交联。