The second approach was based on calculating the root mean square deviation (RMSD) for all the available conformations (see Fig. ). All structures were preliminarily aligned with respect to one of the monomers. Using a specific geometry as a reference, conformers for which the calculated RMSD fell below a predetermined threshold (1.0 Å) were then grouped into the same cluster and removed from the available pool of structures iteratively. When implementing this procedure in a customized script, we had to consider that formally distinct conformations could be related through rotation, reflection, and inversion operations, given the identical nature of the two monomers and their high symmetry. This second strategy is analogous to those routinely used to cluster molecular conformations from molecular dynamics trajectories.