Weird FSC curve dip and cut-off

Dear colleagues,

I used version 3.2.0 to do the homo-refine and NUR. However, the output FSC curves are all weird with a small dip and are cut off near the reported resolution. I tried to play with a larger box size, but no help. I haven’t met with this kind of problem in other projects. Do you have any suggestions?

Thanks for any of your suggestion!


what is your pixel size? It appears you are using binned or downsampled particles

Yes, the pixel size is 1.72A, binned by 2 after extraction from micrograph. The original is 0.43A/pixel (data collected by K3 in super-resolution mode), and was binned by 2 (=0.86, using F-crop factor 1/2) when doing motion correction. Since the particle is elongated, I have to use a large box size, so I downsampled particles.
I just realized that, it’s close to the Nyquist limit, so I need to use the 0.86A/pixel particles, right?

Yes, you are hitting Nyquist, you will want to use the original particles

Thanks for your timely help!