【单选题】Which of the following statements about the R and T state of hemoglobin is wrong?
A.
Although oxygen binds to hemoglobin in either state, it has a significantly higher affinity for hemoglobin in the R state. Oxygen binding stabilizes the R state. When oxygen is absent experimentally, the T state is more stable and is thus the predominant conformation of deoxyhemoglobin.
B.
T and R originally denoted “tense” and “relaxed”, respectively, because the T state is stabilized by a lesser number of ion pairs, many of which lie at the α1β2 (and α2β1) interface.
C.
The binding of oxygen to a hemoglobin subunit in the T state triggers a change in conformation to the R state.
D.
When the entire protein undergoes this transition, the structures of the individual subunits change little, but the αβ subunit pairs slide past each other and rotate, narrowing the pocket between the β subunits. In this process, some of the ion pairs that stabilize the T state are broken and some new ones are formed.
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