Figure 3.

Ball-and-stick diagrams of three heme-binding pockets. Structures are shown for Glycera dibranchiata hemoglobin (PDB ID: 2HBG) (Left), BjFixLH (Center), and the NO transporter protein (PDB ID: 1NP1) (Right) (27, 28). The rightmost and leftmost side chains correspond to the E7 and E11 residues of hemoglobins, respectively. The additional side chain in BjFixLH (red) corresponds to Ile 215. The structures were aligned based on the orientation of the proximal histidine and the porphyrin ring. The atoms are colored as in Fig. 1.