The rearrangement of T state hemoglobin to the R state
A)occurs in each protein subunit independently when its heme binds oxygen.
B)requires the binding of at least three oxygen molecules.
C)increases the ion pairing interactions of the C-terminal amino acids.
D)involves the movement of the Fe(II)into the heme plane.
E)opens a central cavity for BPG binding.

Question

Quizplus · Accepted Answer

The movement of the Fe(II) ion into the heme plane is a key step in the rearrangement of T state hemoglobin to the R state. In the T state, the Fe(II) ion is pulled out of the heme plane towards the proximal His residue, making it less accessible to oxygen binding. In the R state, the Fe(II) ion moves back into the heme plane, making it more accessible to oxygen binding. This conformational change is responsible for the cooperative oxygen binding behavior of hemoglobin.

The Rearrangement of T State Hemoglobin to the R State