Uniform thin ice on ultraflat graphene for high-resolution cryo-EM

作者：Zheng, Liming; Liu, Nan^*; Gao, Xiaoyin; Zhu, Wenqing; Liu, Kun; Wu, Cang; Yan, Rui; Zhang, Jincan; Gao, Xin; Yao, Yating; Deng, Bing; Xu, Jie; Lu, Ye; Liu, Zhongmin; Li, Mengsen; Wei, Xiaoding^*; Wang, Hong-Wei^*; Peng, Hailin^*

来源：Nature Methods, 2023, 20(1): 123-+.

DOI：10.1038/s41592-022-01693-y

• SINGLE-CRYSTAL
• VISUALIZATION
• ORIENTATION
• COMPLEX
• ROUGH
• FLOW

Cryo-electron microscopy (cryo-EM) visualizes the atomic structure of macromolecules that are embedded in vitrified thin ice at their close-to-native state. However, the homogeneity of ice thickness, a key factor to ensure high image quality, is poorly controlled during specimen preparation and has become one of the main challenges for high-resolution cryo-EM. Here we found that the uniformity of thin ice relies on the surface flatness of the supporting film, and developed a method to use ultraflat graphene (UFG) as the support for cryo-EM specimen preparation to achieve better control of vitreous ice thickness. We show that the uniform thin ice on UFG improves the image quality of vitrified specimens. Using such a method we successfully determined the three-dimensional structures of hemoglobin (64 kDa), alpha-fetoprotein (67 kDa) with no symmetry, and streptavidin (52 kDa) at a resolution of 3.5 angstrom, 2.6 angstrom and 2.2 angstrom, respectively. Furthermore, our results demonstrate the potential of UFG for the fields of cryo-electron tomography and structure-based drug discovery.

• 单位
  湍流与复杂系统国家重点实验室; 清华大学; 北京大学; 海南医学院