Having lots of problems figuring this one out. Any help is greatly appreciated!
ID: 61456 • Letter: H
Question
Having lots of problems figuring this one out. Any help is greatly appreciated!
There are many naturally occurring variants of hemoglobin within human populations around the world. Most of these variants arise from single missense mutations that alter one amino acid residue in the a- or ß-subunit. Only some of these variants cause diseases, whereas others have no adverse effects on human health. A few of these variants are listed below. [The first letter indicates the wild-type amino acid; the number indicates the residue; the last letter indicates the mutant amino acid.]
a. E6V in ß-subunit. This mutation occurs on the exterior surface of hemoglobin. This mutation causes sickle-cell anemia.
b. Q23E in a-subunit. This mutation also occurs on the exterior surface of hemoglobin.
c. H87A in a-subunit. This mutation changes the histidine residue that coordinates the iron ion in the heme group.
d. F35Y in ß-subunit. This mutation disrupts interactions between a and ß subunits.
e. H146L in ß-subunit. This mutant disrupts an ion-pair that stabilizes the T state.
f. L136P in a-subunit. This mutation occurs in an a-helix, inside the a-subunit.
g. V67E in ß-subunit. This mutation increases formation of methemoglobin.
Explain your choices for each of the following:
A. The hemoglobin variant that is least likely to cause disease. [50 words or less.]
B. The hemoglobin variant most likely to cause aggregation of hemoglobin into long
filaments. [50 words or less.]
C. The hemoglobin variant with the highest binding affinity for molecular oxygen (O2).[50 words or less.]
Explanation / Answer
A.The hemoglobin variant that is least likely to cause disease is Q23E as it is a alpha subunit of hemoglobin which is more stable and resistant oxidation.
B. It's the E6V a beta subunit variant is most likely to cause aggregation of hemoglobin into long filaments.
C. H146L a beta subunit of hemoglobin variant has the highest binding affinity for molecular oxygen as it stabilizes the 'T' state.
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