Bradykinin, a peptide that helps to regulate blood pressure, h...

Question

Bradykinin, a peptide that helps to regulate blood pressure, has the primary structure Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg.

a. Draw the complete structural formula of bradykinin.

Accepted Answer

Hi, everybody. Welcome back. Our next question says an Aalen is a peptide responsible for regulating pain sensation in the body. There are two forms of anal, one is met an cylin which contains methionine and has the following primary structure. Then we have an amino acid sequence given in those three letter abbreviations Tyr gly glyphemet provide the complete structural formula of met and capella. So what we want to do to draw a structural formula of a polypeptide is first think of the generic structure of an amino acid. And then we'll link those amino acids together by those peptide bonds. And we need to figure out for each of these amino acids. What is the R group we're going to draw on that structure? So we recall that the general structure of amino acid is H two N that nitrogen has a bond to a carbon, which is our alpha carbon. We're gonna label that with a little red alpha, that carbon has a hydrogen. And as a bond to in our group, then as a bond to a carbon group, so bond to a carbon which has a double bond to an oxygen. And then in its solitary form all by itself. That's a carboxylic acid with a link to an, oh, so let's look up the R groups for these various amino acids. So Tyr we have tyrosine gly, we have two glycine phe we have a phenylalanine and met methionine. So let's go to a chart of amino acids and look up what there are groups are. So I've pasted up in red, the various R groups for these amino acids that are in our polypeptide sequence. For Tracy, the R group is CH two bonded to a benzene ring. And then in the paras position from that CH two is an oh group. So it's essentially a phenol attached to ach two attached to the amino acid. Glycine is the simplest amino acid of all. It's our group is simply a hydrogen atom. Phenyl alanine has the R group CH two and then a BTO benzene ring and then methionine, it's our group is CH two ch two sch three. So it has its sulfur atom in it. So we have the various R groups we need. Last thing we need to do is think about how do these amino acids join together in a peptide bond. So we'll go ahead and start our first amino acid, the N terminal. By convention, we always start that on the left. So H to N, then we have an alpha carbon that has a hydrogen on it. And actually in condensed structural formula, I will put this h next to the carbon, we'll put in our first R group since our first amino acid in the list is tyrosine. That's our n terminal amino acid. So we know the tyro attached to the alpha carbon, we have CH two and then that phenol, so we put a benzene ring and then that O group in the paras position from the CH two. So that's our alpha carbon with our group. Now, we know we have the Carbone carbon in the next spot. So carbon double bottled oxygen and now we have a peptide bond. So instead of that carboxylic acid on the amino acid by itself, in a dehydration reaction, going to put up at the top another amino acid. So we can think about how this happens. So this one has an R prime draw the carbonel group eoh the oh group is eliminated from the carboxylic acid. A hydrogen is removed from the amino group on the second amino acid. And that dehydration reaction. So put water molecule eliminated, we then generate the peptide bond. So on the structure I'm drawing, I have that carbonel group instead of that carbon having a link to an oh group, it now has a link to and h from the next amino acid. So I'm going to highlight that peptide bond in blue. That helps me keep oriented and see where my transition to the next amino acid is. Now we'll go to our next amino acids, we have the nitrogen, we move on to the alpha carbon. So ch our next amino acid is glycine, which if you recall has that just a hydrogen as its H group. So I'm going to change, I had ch written, I just changed that to H two for glycine. And then we can go on to the carbonel carbons. C double want to an O and I am already ready for another peptide bond. So put that bond to the and little shorter NH from the next amino acid, I'll again highlight my peptide bond in blue. Now, I see I have another glycine. So my NH will be bound to another carbon, which is my alpha carbon. So once again, since it's glycine, again, that will be CH two and then move on to the carbonel group. So c with a double bond to no. So to my two glycine and now I'm on to phenylalanine. So the carbon carbon now has another peptide bond to the NH of the next amino acid. I like that peptide bond, that nitrogen is bonded to the alpha carbon. So ch now I'm onto phenylalanine. So my R group extending from the alpha carbon is CH two and then a benzene ring try that on there. And then we draw in the carbonel group c double Bonano again, another peptide bond and we're on to our very last amino acid put in the NH highlight that next peptide bond and this one is methionine. I draw my alpha carbon with its hydrogen and then extend my R group. So I have CH two, CH two S and then CH three for methionine for my alpha carbon, I have my carbonel group. And now I'm at the end of my structure here, I'm at the C terminal. So instead of a bond to a nitrogen, I have no more peptide bonds, this carbon in the carbonel group is bound to an oh group. So I have my entire structure for this polypeptide chain, I will just write in and read the amino acids underneath the structure. So the first one is tyra that aromatic ring. Let me have two glycine with just that hydrogen move those over a little bit. So they're more directly underneath the amino acid and then the ch two and benzene ring. So it's sort of a hollye group here. It's phenylalanine and the last one being methionine. So we have those five amino acids with four peptide bonds and we have our entire structure for this polypeptide. See you on the next video.

Struggling with GOB Chemistry?

Bradykinin, a peptide that helps to regulate blood pressure, has the primary structure Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg.
a. Draw the complete structural formula of bradykinin.

Watch next

Primary Protein Structure practice set

Struggling with GOB Chemistry?

Bradykinin, a peptide that helps to regulate blood pressure, has the primary structure Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg.a. Draw the complete structural formula of bradykinin.

Watch next

Primary Protein Structure practice set

Bradykinin, a peptide that helps to regulate blood pressure, has the primary structure Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg.
a. Draw the complete structural formula of bradykinin.