Figure 2. Crystal structure of sRI-sT complex (PDB = 6PSK, 6PXE).
A Ribbon diagram of hetero-tetramer observed in crystals of the sRI-sT complex. sRI subunits are colored in light blue, and sT - in tan.
B Surface representation of the sRI-sT complex colored by electrostatic potential, the orientation is the same as on the panel A.
C 90° rotated view of the sRI-sT complex depicted on the panel A. GAF domain homolog structure (pdb ID: 2ool) shown as green licorice ribbon is superimposed on both sT subunits for a comparison. Putative positions for the elements not covered by the crystal structure are shown as dash outlined boxes: blue for the SAR domains of RI, and red for the transmembrane (TM) helix and α0 of T.
D Elements of the structure are marked on the ribbon representation of the sRI bound form of the sT. Clipped surface view of the overlaid GAF domain homolog structure (pdb ID: 2ool) is shown in green to illustrate that LC loop of sT blocks putative GAF pocket (highlighted by purple line).