Question

Find out the sequence of amino acids from N-terminal to C-terminal in given polypeptide chain. 

 

• A. Thr-Ser-Asp-Gly-Ala
• B. Ser-Thr-Asp-Gly-Ala
• C. Ser-Asp-Thr-Gly-Ala
• D. Thr-Ser-Asp-Gly-Ala

Hint:

Peptide sequences are always read from the N-terminal (free amino group) to the C-terminal (free carboxyl group).

Answer 1

The Correct Option is A

Identify R-groups in the peptide backbone $\text{-NH-CH(R)-CO-}$:
1. $\text{R} = \text{-CH(OH)CH}_3$. Amino acid: Threonine (Thr).
2. $\text{R} = \text{-CH}_2\text{OH}$. Amino acid: Serine (Ser).
3. $\text{R} = \text{-CH}_2\text{COOH}$. Amino acid: Aspartic Acid (Asp).
4. $\text{R} = \text{H}$. Amino acid: Glycine (Gly).
5. $\text{R} = \text{-CH}_3$ (at C-terminal). Amino acid: Alanine (Ala).
Sequence: Thr-Ser-Asp-Gly-Ala.