Application of super-resolution and correlative double sampling in cryo-electron microscopy

Journal article

Developments in cryo-EM have allowed atomic or near-atomic resolution structure determination to become routine in single particle analysis (SPA). However, near-atomic resolution structures determined using cryo-electron tomography and sub-tomogram averaging (cryo-ET STA) are much less routine. In this paper, we show that collecting cryo-ET STA data using the same conditions as SPA, with both correlated double sampling (CDS) and the super-resolution mode, allowed apoferritin to be reconstructed out to the physical Nyquist frequency of the images. Even with just two tilt series, STA yields an apoferritin map at 2.9 Å resolution. These results highlight the exciting potential of cryo-ET STA in the future of protein structure determination. While processing SPA data recorded in super-resolution mode may yield structures surpassing the physical Nyquist limit, processing cryo-ET STA data in the super-resolution mode gave no additional resolution benefit. We further show that collecting SPA data in the super-resolution mode, with CDS activated, reduces the estimated B-factor, leading to a reduction in the number of particles required to reach a target resolution without compromising the data size on disk and the area imaged in SerialEM. However, collecting SPA data in CDS does reduce throughput, given that a similar resolution structure, with a slightly larger B-factor, is achievable with optimised parameters for speed in EPU (without CDS)

Authors: Sheng, Y; Harrison, PJ; Vogirala, V; Yang, Z; Strain-Damerell, C

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Royal Society of Chemistry
• Journal: Faraday Discussions
• Volume: 240
• Pages: 261-276
• Publication date: 2022-11-08
• DOI: 10.1039/d2fd00049k
• EISSN: 1364-5498
• ISSN: 1359-6640
• Language: English
• Keywords: Computer science; Electron microscope; Physics; Optics; Sampling (signal processing); Materials science; Correlative; Microscopy; Artificial intelligence; Superresolution; Resolution (logic)