Biophysical Society Thematic Meeting | Trieste 2024

Emerging Theoretical Approaches to Complement Single-Particle Cryo-EM

Tuesday Speaker Abstracts

EXPLOITING THE FULL POTENTIAL OF CRYOGENIC ELECTRON MICROSCOPY MAPS Paulina M Dominiak 1 ; 1 University of Warsaw, Biological and Chemical Research Centre, Department of Chemistry, Warszawa, Poland Cryogenic electron microscopy (cryo-EM) experiments yield three-dimensional images of electrostatic potential of molecules. Currently, these images are only used to obtain information about the position of atoms in space. However, there is much more information in them. The electrostatic potential carries information about the delicate balance between the positive potential generated by atomic nuclei and the negative potential generated by electron density. Thanks to this, it is very sensitive to changes in the protonation of functional groups, the state of metal oxidation, and the redistribution of electron density due to the formation of chemical bonds and intermolecular interactions. All these phenomena can be studied by analyzing images from an electron microscope. However, to make this possible, appropriate electrostatic potential models are needed, which will allow for reliable verification of the hypotheses through direct comparison with experimental data. During the lecture, I will present electron density models, and therefore electrostatic potential models, that have been developed over the years in the field of quantum crystallography, focusing on X-ray diffraction experiments [1]. These models are currently being adapted for electron diffraction [2] and microscopy [3], which will enable the full potential of these experiments to be explored.[1] Kulik M, Dominiak PM (2022) Comp. Struct. Biotech. J., 20, 6237-6243 [DOI: 10.1016/j.csbj.2022.10.018][2] Kulik M, Chodkiewicz ML, Dominiak PM (2022) Acta Cryst. D 78, 1010–1020 [DOI: 10.1107/S2059798322005836][3] Bick T, Dominiak PM, Wendler P (2024) BBA Advances, 5, 100113 [DOI: 10.1016/j.bbadva.2024.100113]The National Science Center, Poland, provided the funding for the research presented in this work under the grants 2020/39/I/ST4/02904 and 2017/27/B/ST4/02721.

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