Application of super-resolution and correlative double sampling in cryo-electron microscopy
Sheng, Yuewen ; Harrison, Peter J ; Vogirala, Vinod ; Yang, Zhengyi ; Strain-Damerell, Claire ; Frosio, Thomas ; Himes, Benjamin A ; Siebert, C Alistair ; Zhang, Peijun ; Clare, Daniel K
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Abstract
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).
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Sheng Y, Harrison PJ, Vogirala V, Yang Z, Strain-Damerell C, Frosio T, Himes BA, Siebert CA, Zhang P, Clare DK. Application of super-resolution and correlative double sampling in cryo-electron microscopy. Faraday Discuss. 2022 Nov 8;240(0):261-276. doi: 10.1039/d2fd00049k. PMID: 35938521; PMCID: PMC9642007.