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2023-06-28T07:37:54Z

Created page with "== Citation == Heymann, J. Bernard. The Ewald sphere/focus gradient does not limit the resolution of cryoEM reconstructions. 2023. J. Structural Biology: X, Vol. 7, p. 100083..."

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== Citation ==

Heymann, J. Bernard. The Ewald sphere/focus gradient does not limit the resolution of cryoEM reconstructions. 2023. J. Structural Biology: X, Vol. 7, p. 100083

== Abstract ==

In our quest to solve biomolecular structures to higher resolutions in cryoEM, care must
be taken to deal with all aspects of image formation in the electron microscope. One of
these is the Ewald sphere/focus gradient that derives from the scattering geometry in
the microscope and its implications for recovering high resolution and handedness
information. While several methods to deal with it has been proposed and
implemented, there are still questions as to the correct approach. At the high
acceleration voltages used for cryoEM, the traditional projection approximation that
ignores the Ewald sphere breaks down around 2-3 Å and with large particles. This is
likely not crucial for most biologically interesting molecules, but is required to
understand detail about catalytic events, molecular orbitals, orientation of bound water
molecules, etc. Through simulation I show that integration along the Ewald spheres in
frequency space during reconstruction, the “simple insertion method” is adequate to
reach resolutions to the Nyquist frequency. Both theory and simulations indicate that
the handedness information encoded in such phases is irretrievably lost in the
formation of real space images. The conclusion is that correct reconstruction along the
Ewald spheres avoids the limitations of the projection approximation.

== Keywords ==

== Links ==

https://www.sciencedirect.com/science/article/pii/S2590152422000241

== Related software ==

== Related methods ==

== Comments ==

2023Heymann Ewald - Revision history

WikiSysop: Created page with "== Citation == Heymann, J. Bernard. The Ewald sphere/focus gradient does not limit the resolution of cryoEM reconstructions. 2023. J. Structural Biology: X, Vol. 7, p. 100083..."