Figure 3.
Fig. 3. Active site of IDO–PI complex. (A) Stereoview of
the residues around the heme of IDO viewed from the side of heme
plane. The proximal ligand H346 is H-bonded to wa1. The
6-propionate of the heme contacts with wa2 and R343 N . The
wa2 is H-bonded to wa1, L388 O, and 6-propionate. Mutations of
F226, F227, and R231 do not lose the substrate affinity but
produce the inactive enzyme. Two CHES molecules are bound in the
distal pocket. The cyclohexan ring of CHES-1 (green) contacts
with F226 and R231. The 7-propionate of the heme interacts with
the amino group of CHES-1 and side chain of Ser-263. The
mutational analyses for these distal residues are shown in Table
1. (B) Top view of A by a rotation of 90°. The proximal
residues are omitted.
. The
wa2 is H-bonded to wa1, L388 O, and 6-propionate. Mutations of
F226, F227, and R231 do not lose the substrate affinity but
produce the inactive enzyme. Two CHES molecules are bound in the
distal pocket. The cyclohexan ring of CHES-1 (green) contacts
with F226 and R231. The 7-propionate of the heme interacts with
the amino group of CHES-1 and side chain of Ser-263. The
mutational analyses for these distal residues are shown in Table
1. (B) Top view of A by a rotation of 90°. The proximal
residues are omitted.