FIGURE 8.

The ligand binding site of NR and loop movement. A, details of the tyramine binding site. B, surface view of the NR ligand binding site showing tyramine and NADP⁺. C, details of the piperonal binding site. D, comparison of the 209–220 loop movement in the NR·NADP⁺ (cream) and NR·NADP⁺·tyramine complexes. The positions of Thr²¹³ and Phe²¹⁶ are shown in each structure for reference. The positions of the hinge residues Arg²⁰⁹ and Lys²²⁰ are noted by triangles.