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bioRxiv · 10.1101/2021.10.12.464113

Single-particle cryo-EM structures from iDPC-STEM at near-atomic resolution

Lazic, I.·Wirix, M.·Leidl, M. L.·Haas, F. d.·Beckers, M.·Pechnikova, E. V.·Mueller-Caspary, K.·Egoavil, R.·Bosch, E. G. T.·Sachse, C.
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Abstract

Electron cryo-microscopy (cryo-EM) is becoming one of the routine tools for structure determination of biological macromolecules. Commonly, molecular images are obtained by conventional transmission electron microcopy (CTEM) using underfocus and subsequently computationally combined into a high-resolution 3D structure. Here, we apply scanning transmission electron microscopy (STEM) using the integrated differential phase contrast mode also known as iDPC-STEM to the cryo-EM test specimen of tobacco mosaic virus (TMV). The micrographs show complete contrast transfer to high resolution and enable the cryo-EM structure determination at 3.5 [A] resolution using single-particle based helical reconstruction. A series of cryo-EM TMV maps was resolved at near-atomic resolution taken at different convergence semi-angle (CSA) beams and share identical features with maps obtained by CTEM of a previously acquired same-sized TMV data set. The associated map B-factors from iDPC-STEM match those obtained by CTEM recordings using 2nd generation direct electron detection devices. These data show that STEM imaging in general, and in particular the iDPC-STEM approach, can be applied to vitrified single-particle specimens to determine near-atomic resolution cryo-EM structures of biological macromolecules.

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Lazic, I., Wirix, M., Leidl, M. L., Haas, F. d., Beckers, M., Pechnikova, E. V., Mueller-Caspary, K., Egoavil, R., Bosch, E. G. T., Sachse, C.. 2021-10-12. Single-particle cryo-EM structures from iDPC-STEM at near-atomic resolution. https://doi.org/10.1101/2021.10.12.464113

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