S1-NTD (PDB 6VXX) Showing Residues at Boundaries of Invisible (Disordered) Segments and the Location of the Two Visible Tryptophan (TRP) Residues. These are the last visible residues of the non-disordered region bounding a disordered region, and this figure shows how the missing sections result in “cut ends” in displays of the reported three dimensional structure.