Figure 5.

Snapshots of the heme pocket⁴⁵ during the MD trajectory shown in Figure 4. (a) The R_ε configuration has N_ε–H oriented toward the CO, and the N_δ oriented toward the solvent. (b) In the B_ε configuration, the imidazole ring of His64 has undergone a rotation around the C_β–C_δ bond so that N_ε–H is oriented away from the CO ligand and N_δ is inside the heme pocket.