Identify the amino acid, NOT having nitrogen atom in a side chain.

Step-by-step solution

The structures of the side chains (R groups) for the given amino acids are as follows: Asparagine: The side chain is -CH₂CONH₂ , which contains an amide nitrogen. Histidine: The side chain contains an imidazole ring, which has two nitrogen atoms. Tryptophan: The side chain contains an indole ring, which has a nitrogen atom. Threonine: The side chain is -CH(OH)CH₃ , which contains only carbon, hydrogen, and oxygen atoms. It does not contain any nitrogen atom. Therefore, Threonine is the amino acid that does not have