Exploiting prior knowledge about biological macromolecules in cryo-EM structure determination

Autor: Dari Kimanius, Gustav Zickert, Takanori Nakane, Jonas Adler, Sebastian Lunz, Carola-Bibiane Schönlieb, Ozan Öktem, Sjors H. W. Scheres
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: IUCrJ, Vol 8, Iss 1, Pp 60-75 (2021)
Druh dokumentu: article
ISSN: 2052-2525
20522525
DOI: 10.1107/S2052252520014384
Popis: Three-dimensional reconstruction of the electron-scattering potential of biological macromolecules from electron cryo-microscopy (cryo-EM) projection images is an ill-posed problem. The most popular cryo-EM software solutions to date rely on a regularization approach that is based on the prior assumption that the scattering potential varies smoothly over three-dimensional space. Although this approach has been hugely successful in recent years, the amount of prior knowledge that it exploits compares unfavorably with the knowledge about biological structures that has been accumulated over decades of research in structural biology. Here, a regularization framework for cryo-EM structure determination is presented that exploits prior knowledge about biological structures through a convolutional neural network that is trained on known macromolecular structures. This neural network is inserted into the iterative cryo-EM structure-determination process through an approach that is inspired by regularization by denoising. It is shown that the new regularization approach yields better reconstructions than the current state of the art for simulated data, and options to extend this work for application to experimental cryo-EM data are discussed.
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