(A) Single subunit of the in situ structure is in blue and an apposing chain from the crystal structure is in yellow. (B) Superposition of single subunits, exposing structural differences between the crystal structure and the in situ structure. The curved arrow indicates the pivoting of the Wing domain by ~8° in the in situ structure. (C) The two dodecamers overlaid, viewed from Crown (top domain in A), along the tunnel axis. Dodecamers are superposed based on residues 26–376 (Clip, Stem, and Wing), revealing a ~13° rotation of the Crown domain about the tunnel axis. (D) Overlay of in situ (blue) and crystal structure (yellow), ribbon diagram, with side-chains shown. (E) Van der Waals surface of the crystal structure (PDB 6IBG) showing tunnel loop-constricted region, with tunnel colouring by the hydrophobicity on the Kyte-Doolittle scale where white is hydrophobic and brown is hydrophilic, and same for (F) but for the in situ structure (PDB 6QJT). Diameters of most constricted part of tunnels measured from Van der Waals surfaces are shown.