Draw the structural formula for each of the following peptides:
b. KCG

Question

Draw the structural formula for each of the following peptides:

b. KCG

Accepted Answer

All right. Hello everyone. So this question is asking us to draw the skeletal structure for the peptide HSG and to ignore stereo chemistry. So in this particular case, right, we're using the one letter abbreviations which means that we have a total of three amino acids in this particular peptide. So it's a tripeptide. Now recall that when drawing out peptides, they are done from end to c. So as you read the structure of the peptide from left to right, you're doing so from the N terminus to the C terminus, the N terminus, if you recall is the amino acid with the free amino group, whereas the C terminus is the amino acid with the free carboxylate group. So here let's go ahead and identify the amino acids first. So we have the three letter abbreviations or one letter for each. Now, sometimes if the first letter of an amino acid is unique, that's going to be the one letter abbreviation for that amino acid. So for example, H would stand for his city and s would stand for searing. Now, G is not an example of a unique first letter because multiple different amino acids have the first letter being G, but the most common it is the most common and the one letter abbreviation G matches glycine. So we have Histidine sine and glycine. So before we go ahead and draw out the side chains of these amino acids, I want to just go ahead and draw out the backbone. Now, the good news is that the backbone of a peptide is going to be the same in structure and it's going to follow a very similar pattern. So let's start with the N terminus which would have a free proton amino group. And so the pattern is as follows. Right, first, from the N terminus from the free amino group, we have the alpha carbon followed by the carbon carbon of the carboxylic group. So now at this point, we're going to introduce the peptide bond between two amino acids in the peptide itself. So instead of drawing out the hydroxy group of the carboxylic acid group, I would instead add the amino group of the second amino acid groups. So just to clarify the carbon carbon of the first amino acid is connected now to the amino group of the second amino acid. And so from the second amino group, we follow the same pattern, we have the alpha carbon where the side chain goes. And then the second car bottle followed by the amino group of the third amino acid. So at this point, we are at the third and final amino acid for this peptide. So we have one more alpha carbon and one more car bottle. But this time recall that this is the C terminus. So we would have a free carboxylic group at this end. So here recall the peptide bonds in between amino acids are created by the removal of water. So we have the loss of the oxygen from the carboxylic acid group and two hydrogens from the amino group to create an amide linkage. So now we can go ahead and add our side chains to the three alpha carpets. So starting off on the left side, we can add his. So that's one additional carbon branching from the alpha carbon followed by our ring structure. And keep in mind that one of the nitrogens of histidine would have a positive charge to it. One of the nitrogens in the ring moving on. Now to sir, the side chain of Cine is simply one additional carbon followed by a hydroxy group. And last but not least we have glycine, but recall that the side chain of glycine is simply another hydrogen. So there's no need for me to add anything else from the alpha carbon associated with glycine and there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful. Go ahead and highlight my answer here and thank you again for watching.

Draw the structural formula for each of the following peptides:
b. KCG

Verified video answer for a similar problem:

Key Concepts

Peptide Structure

Amino Acids

Structural Formula Representation

Draw the structural formula for each of the following peptides:b. KCG

Verified video answer for a similar problem:

Key Concepts

Peptide Structure

Amino Acids

Structural Formula Representation

Draw the structural formula for each of the following peptides:
b. KCG