Electron radiation damage hinders the high-resolution cryogenic transmission electron microscopy (cryo-TEM) imaging of macromolecules. In this work, sodium ascorbate (SA) was used to eliminate reactive oxygen species generated during electron radiation, thereby enhancing the electron radiation resistance of macromolecular samples in cryo-TEM experiments. The effectiveness of SA on protecting sample morphology and structure was investigated for representative types of macromolecular samples, including collagen, cellulose, liposome, and apoferritin, and compared with other radical scavengers. Our findings revealed that SA provided the most effective protection for collagen, increasing its dose limit by more than 40%. Similar effects were observed for cellulose and apoferritin. Importantly, the addition of SA does not change the three-dimensional structure of apoferritin, as confirmed by a 2.2 Å resolution single particle analysis, further indicating the practicality of the method.

中文翻译：

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使用抗坏血酸钠在冷冻 TEM 成像中增强大分子的电子辐射抗性


电子辐射损伤阻碍了大分子的高分辨率低温透射电子显微镜 （cryo-TEM） 成像。在这项工作中，抗坏血酸钠 （SA） 用于消除电子辐射过程中产生的活性氧，从而增强冷冻 TEM 实验中大分子样品的电子辐射抵抗力。研究了 SA 对代表性大分子样品类型（包括胶原蛋白、纤维素、脂质体和脱铁蛋白）保护样品形态和结构的有效性，并与其他自由基清除剂进行了比较。我们的研究结果表明，SA 为胶原蛋白提供了最有效的保护，将其剂量限制提高了 40% 以上。对纤维素和脱脂铁蛋白也观察到类似的效果。重要的是，添加 SA 不会改变脱铁蛋白的三维结构，2.2 Å 分辨率的单颗粒分析证实了这一点，进一步证明了该方法的实用性。