Will a mutation from Distal histidine to phenylalanine shift the binding curve of hemoglobin?Will it shift the curve to the left or right, shift to myoglobin or no longer bind to O2?

The mutation in hemoglobin at B82 Lys → Asp results in lowered O,-binding affinity compared to normal hemoglobin. B82 is one of the residues that lines the 2,3-BPG binding site (see Figure 7.29; B82 is adjacent to His143). Based on the location of this residue and the differences between Lys and Asp, sug- gest a rationale for the observed reduction in Oz-binding affinity.

4)

A very new Hemoglobin variant, called Hb simplex, has just been identified in patients with hypoxia (i.e. patients for whom the oxygenation of organs is not properly accomplished). However, this variant is able to bind dioxygen with a Kd which is significantly lower to that of Hemoglobin from normal patients. This effect has been associated with the substitution of a Lys by a Met at two distinct sites of the b subunit of Hemoglobin : one site close to the N-terminus, and the other site close to the C-terminus of the polypeptide chain. Most importantly, these 2 sites are known to be involved in the maintain of the physical interactions between the subunits a and b in Hemoglobin. 1) The aforementioned Hb simplex mutations lead to a loss of physical interactions between the subunits a and b. What type(s) of chemical bonds between the 2 subunits (i.e. covalent, electrostatic, ion-dipole, dipole-dipole, van der waals) would you hypothesize to be affected by these mutations? explain. 2)…