In sickle cell anaemia, the sequence of amino acid from first to seventh position of `beta`-chain of haemoglobin S (HbS) is

Options

A. His, Leu, Thr, Pro, Glu, Val, Val
B. Val, His, Leu, Thr,Pro,Val, Glu
C. Thr, His Pro, Val, Pro, Val, Glu
D. Glu, His, Leu, Pro, Val, Glu, Glu

Answer

To solve the question regarding the sequence of amino acids from the first to the seventh position of the beta chain of hemoglobin S (HbS) in sickle cell anemia, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Sickle Cell Anemia**:
- Sickle cell anemia is caused by a genetic mutation in the beta-globin gene of hemoglobin. This mutation is a point mutation that leads to a change in one amino acid in the beta chain of hemoglobin.

2. **Identify the Mutation**:
- The specific mutation occurs at the 6th position of the beta chain. In normal hemoglobin (HbA), the amino acid at this position is glutamic acid, which is coded by the codon GAG. In hemoglobin S (HbS), this codon changes to GUG, resulting in the amino acid valine replacing glutamic acid.

3. **List the Amino Acids**:
- The sequence of amino acids from the 1st to the 7th position in the beta chain of HbS is as follows:
1. Valine (1st position)
2. Histidine (2nd position)
3. Leucine (3rd position)
4. Threonine (4th position)
5. Proline (5th position)
6. Valine (6th position, mutated)
7. Glutamic acid (7th position)

4. **Final Sequence**:
- Therefore, the complete sequence of the first seven amino acids in the beta chain of hemoglobin S is:
- Valine, Histidine, Leucine, Threonine, Proline, Valine, Glutamic acid.

5. **Select the Correct Option**:
- Based on the provided options, the correct answer is the sequence mentioned above.