Local motion correction leads to worse NU refinement

Motion Correction
1

Dear All,

I have a dataset that yielded a NU refinement at a resolution of ~2.5 Å.
J129_posterior_precision_directional_distribution_iteration_010

J129_fourier_space_slices_iteration_010
J129_fourier_space_slices_iteration_0101089×336 69.8 KB

then I tried to apply local motion correction and re-perform the refinement, that now presents a different viewing direction distribution and a very unusual Posterior Precision Directional Distribution.
J162_posterior_precision_directional_distribution_iteration_005

J162_fourier_space_slices_iteration_005
J162_fourier_space_slices_iteration_0051089×331 71.7 KB

The improvements on the resolution are marginal, and the map obtained looks weird.

Has anybody encountered this problem before and has any suggestion?

Best,
Giovanni

2

Haven’t seen this before, but did you try a quick 2D classification after local motion correction? I wonder if a small percentage of badly behaved particles are throwing things off (this sometimes happens after polishing)

1 Like
3

What happens with local refinement?

As Oli says, if there are enough bad particles still hiding in the data, it can cause all sorts of strange behaviour.

Do your particles still look like particles, or do they now look like noise?