用于高分辨率冷冻电子显微镜的双亲和石墨烯片

清华大学王宏伟团队开发了用于高分辨率冷冻电子显微镜的双亲和石墨烯片。相关研究成果于2023年4月3日发表在《美国化学会杂志》。

随着冷冻电子显微镜（cryo-EM）的发展，单粒子方法可以有效地重建大分子的高分辨率结构。然而，在样本制备阶段，挑战可能仍然存在。具体来说，蛋白质倾向于在空气-水界面吸附，并在玻璃质冰中表现出优选的方向。

为了克服这些挑战，研究人员探索了用两种不同的亲和配体修饰的双亲和石墨烯（DAG）作为低温EM样品制备的支撑材料。配体可以与相应标记颗粒上的不同位点结合，从而产生颗粒的各种取向分布，并阻止蛋白质颗粒吸附到空气-水界面上。正如预期的那样，在两种不同的蛋白质情况下，包括严重急性呼吸系统综合征冠状病毒2型刺突糖蛋白，与单一功能化石墨烯相比，DAG表现出对靶大分子的高结合特异性和亲和力，导致颗粒欧拉角分布更加平衡。

研究预计，DAG网格将实现简单有效的三维（3D）重建，用于冷冻EM结构的确定，为未来的研究提供一种稳健和通用的技术。

附：英文原文

Title: Dual-Affinity Graphene Sheets for High-Resolution Cryo-Electron Microscopy

Author: Hang Cheng, Liming Zheng, Nan Liu, Congyuan Huang, Jie Xu, Ye Lu, Xiaoya Cui, Kui Xu, Yuan Hou, Junchuan Tang, Zhong Zhang, Jing Li, Xiaodan Ni, Yanan Chen, Hailin Peng, Hong-Wei Wang

Issue&Volume: April 3, 2023

Abstract: With the development of cryo-electron microscopy (cryo-EM), high-resolution structures of macromolecules can be reconstructed by the single particle method efficiently. However, challenges may still persist during the specimen preparation stage. Specifically, proteins tend to adsorb at the air–water interface and exhibit a preferred orientation in vitreous ice. To overcome these challenges, we have explored dual-affinity graphene (DAG) modified with two different affinity ligands as a supporting material for cryo-EM sample preparation. The ligands can bind to distinct sites on the corresponding tagged particles, which in turn generates various orientation distributions of particles and prevents the adsorption of protein particles onto the air–water interface. As expected, the DAG exhibited high binding specificity and affinity to target macromolecules, resulting in more balanced particle Euler angular distributions compared to single functionalized graphene on two different protein cases, including the SARS -CoV-2 spike glycoprotein. We anticipate that the DAG grids will enable facile and efficient three-dimensional (3D) reconstruction for cryo-EM structural determination, providing a robust and general technique for future studies.

DOI: 10.1021/jacs.3c00659

Source: https://pubs.acs.org/doi/10.1021/jacs.3c00659