Fig. 1. Molecular architecture of CRY2–PHR.

a Overall structure of CRY2–PHR bound to FAD shown in top view surface representation, and side view with the four monomers A–D assembled to a tetramer (A, B, C, D represented by cyan, pink, purple, and green respectively). FAD molecules are shown in yellow. Head to head and head to tail interfaces are denoted by brackets as H–H and H–T respectively. b Close-up view of monomer A of AtCRY2-PHR_tetramer represented in cartoon. Secondary structure of the indicated domains shown as cylinders for helices and beta strands and labeled in black. N-terminal α/β domain (blue), C-terminal α-domain (light brown), and flexible connector loop (red) are highlighted. c Close-up view of bound FAD represented in sticks and colored by elements: yellow (carbon), blue (nitrogen), red (oxygen), phosphate (orange).