Hi,
What resolution do you get if you run relion_reconstruct
without --ewald? The difference between this value and Refine3D
reflects the effect of marginalisation.
The difference is usually tiny but your case might be an exception.
Also, according to the formula in
https://www.ncbi.nlm.nih.gov/pubmed/16384646,
the effect of Ewald sphere curvature for a 300 A particle should be
very small at ~ 2.9 A.
Best regards,
Takanori Nakane
> Dear all,
>
> I obtained a 3D structure of a spherical virus with a diameter of about
> 300 A by RELION-3 beta.
> 3D auto refine and postprocess produced a 2.88 A resolution map.
>
> Then, I tried relion_reconstruct --ewald with and without
> --reverse_curvature as,
>
> relion_reconstruct --i Refine3D/job172/run_data.star --o
> reverse_half1.mrc --subset 1 --angpix 1.24 --ctf --ewald --mask_diameter
> 400 --sectors 2 --width_mask_edge 5 --sym I1 --reverse_curvature
>
> Here Refine3D/job172/run_data.star is output from 3D auto refine.
>
> Postprocessing the resulting maps showed 2.91A and 3.05A resolutions
> with and without --reverse_curvature, respectively.
>
> So I think Ewald sphere correction is effective, but the resolution by
> relion_reconstruct --ewald is lower than by auto refine (with no Ewald
> sphere correction).
> I wonder if there is a way to improve the resolution of the original 3D
> auto-refined map (2.88 A resolution) by Ewald sphere correction.
>
> Thank you in advance,
> Best regards,
>
> Tasuku
>
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