Figure 7.

(a–d) Force-constant profiles for the four monomeric units of chicken Hb (black lines) and force-constant variations Δk = k_{human Hb} − k_{chicken Hb} for the monomers (red lines). The red secondary structures plot at the top of (a,b) indicate the localization of α-helices along the sequences of the α- and β-units (1 kcal mol⁻¹ Å⁻² = 0.7 N m⁻¹).