Filament walking

I see @Itai, thanks for that additional information! If you have particle positions which correspond to A points, you may be able to use cryosparc-tools to find B positions. Here’s the general process I’d use, applying the below steps to each micrograph:

  1. Load in all particle positions
  2. Filter out just the A subset.
  3. For each A particle:
    a. Add and subtract the A/B offset distance from filament/position_A. This is the position of the particle along the filament contour, in Å. For example, if the filament is 50 Å long and the particle was halfway along the filament, this value would be 25. Note that this does take into account filament curvature.
    b. Find particles which are within some small distance from the offset filament/position_A along the filament, if any. These would be your candidate B particles.

An explanation of all of the filament parameters is available here.

I hope that is helpful! Please let me know if there’s anything else I can clear up for you!