Fitting and refinement with Phenix or Refmac was tried but did not work, because these automatic procedures attempted to e.g. fit the membrane-inserted β-hairpins into the amphipol density around the hydrophobic part of the pore. The densities of amphipol and protein are comparable at 4-4.5 Å resolution, and only manual fitting can differentiate between them. Therefore, it was unfortunately not possible to employ automatic model fitting and refinement. It is well known that refinement of x-ray structures at similar resolutions also does not work, for the same reasons.