Question

16.12 Draw the condensed structural formula for cach of the following peptides, and give its three-letler and one-letler abbreviations:

a. prolyl aspartate

b. threonyl leucine

c. methionylglutaminyllysine

d. histidylglycylghutamylisoleucine

Short answer

The structures of peptides are shown below, along with the one-letter and three-letter amino acid abbreviations:

(Part a)

(Part b)

(Part c)

(Part d)

Step-by-step solution

Introduction(Part a) 

Amino acids are the building blocks of proteins. These contain one hydrogen atom, one amine group $\left(-{\mathrm{NH}}_2\right)$, one carboxylic acid group $(-\mathrm{COOH})$ and one side chain (R group) attached to the central carbon atom.

The hydroxyl group of the carboxylic acid and the hydrogen group of the amino group combine to form a water molecule and an amide linkage. The "peptide bond" is an amide bond formed between one amino acid's carboxylic group and the amino group of another amino acid.

Given data (Part a) 

Peptide structures are shown below, along with one-letter and three-letter amino acid prolyl aspartate abbreviations.

Explanation (part a)

Given data (Part b) 

Peptide structures are shown below, along with one-letter and three-letter amino acid threonyl leucine abbreviations.

Explanation (part b)

Given data (Part c) 

Peptide structures are shown below, along with one-letter and three-letter amino acid methionylglutaminyllysine abbreviations:

Explanation (part c)

Given data (Part d) 

Peptide structures are shown below, along with one-letter and three-letter amino acid histidylglycylghutamylisoleucine abbreviations.

Explanation (part d).