Question

If a Lys residue that interacts with 2,3-bisphosphoglycerate (BPG) in the central cavity of hemoglobin is changed to a Ser residue, how would this affect hemoglobin behaviour?
a. The T state would be more stable.
b. Oxygen binding would be more sensitive to pH.
c. The T state would be less stable
d. Oxygen binding would be less sensitive to pH.

Answer 1

Answer: Option (c) is the correct answer.

Explanation:

When there will be interaction between 2,3-bisphosphoglycerate (BPG) and Lys residue in the central cavity of hemoglobin then it will change into Ser residue. After that, the it will lead to less stable formation of deoxygenated state (T state).

Since, serine is not a charged amino acid therefore, it will lead to a decrease in the binding affinity of hemoglobin for 2,3-bisphosphoglycerate.

As a result, stability of the T state will decrease.

Thus, we can conclude that in the given situation the T state would be less stable.