Hi @wjnicol,
Thanks for sharing this! I think this might be a very similar case to what @olibclarke reported in this post.
cFSCs are computed by considering a cone in Fourier space, whereas relative signal uses a ‘wobbly slice’ (or what we refer to as a torus) so that we can link poor relative signal to viewing directions via the Fourier slice theorem.
If that ‘missing wedge’ of correlation in the 3DFSC plot above is much more evident with conical regions as opposed to slices, the relative signal plots will not contain the same worst-case correlations you see in the cFSC plot.
A couple questions:
- Is this a relatively small target (< 100 kDA?)? Does it have a micelle?
- Does the density itself show signs of preferred orientation?
We’re actively investigating this phenomenon so your input is very much appreciated!
Thanks,
Valentin