Fig. 3.

Crystal structure comparison between apo-AnaCTDH and CTD OCP^O (PDB code: 5UI2). a CTD-OCP (PDB code: 5UI2, orange) and apo-AnaCTDH (blue) structures are superimposed. Both elongation of β6 strand and shortening of the loop connecting β5 and β6 strands are observed for apo-AnaCTDH. b These differences lead to spatial changes in both E244/E69 and W277/W102. In contrast, Y201/Y26 and W288/W109 overlap well in both structures. c Cartoon representation of CTDH (blue shades) super-positioned with CTD of OCP^O (orange shades). The C-terminal tail changes its orientation (indicated by dashed arrow) substantially from an external position (tail in orange) to an internal position for apo-AnaCTDH (tail in light blue). The position of the carotenoid molecule (yellow stick representation) is preserved from the 5UI2 structure. d Same as c but rotated clockwise by 90°. e Same as b but with amino acids known to be substantially perturbed in their solvent accessibility upon holo-to-apo transition in CTD-OCP