Aim high and draw the following peptide: A-I-M-H-I-G-H.

Question

Accepted Answer

Alright. So this practice problem wants us to aim high and draw the following peptide, aim high. And so what we're gonna do is follow our 3 steps for drawing a peptide. And in the first step, we're going to draw the peptide backbone and identify the alpha carbons. And so when we're drawing the peptide backbone, we're going to draw an NCC set or a nitrogen carbon carbon set for each amino acid residue in the peptide. And since there's a total of 7 amino acid residues in the peptide, there's gonna be a total of 7 ncc sets. So let's get started with drawing those 7 ncc sets. So what we have is a nitrogen, carbon, carbon, that's 1 ncc set, then we need more of those, so ncc that's 2, ncc that's 3, ncc that's 4, ncc that's 5, ncc that's 6, and ncc that's 7. So now we have all 7 of our ncc's, the next step is going to be to identify the alpha carbons and the alpha carbons going to be the middle carbon in each of these NCC sets. So here's an alpha carbon here, here's an alpha carbon here, here's an alpha carbon, here's an alpha carbon, here's an alpha carbon, alpha carbon, and last but not least, alpha carbon. Alright. So then we need to, remember that at the end terminal end, there's gonna be a free ionizable amino group. So we already know this, so it's gonna be an NH 3 plus and at the opposite end, the carboxyl end, there's gonna be a free and ionizable carboxylate group, a COO minus. And so, essentially that is it for step number 1. And in step number 2, we're going to draw in all of the carbonyl groups and consider amino acid chirality. And so when we're drawing carbonyl groups, we draw them on the carbons that are not labeled with the alpha carbon symbol over here. So we can draw them on all of these carbons that are indicated as shown, and we are almost done and that is it. And so now we need to consider amino acid chirality, which is just remembering that life predominantly uses l amino acids in their proteins. And so we need to make sure that our amino acids have the l configuration, and the way that we do that is by remembering that when the R group is going up, I'm sorry, when the R group is going down, it should be on a dash and when the R group is going up, it should be on a wedge. And so looking at our first alpha carbon over here, which we know is going to have an r group, notice that it's pointing in the upwards direction here, so that means that this alpha carbon is going to be have a r group that's going up, and when the r groups going up it's going to be on a wedge. And so over here what we can do is put a wedge. Now, this alpha carbon is going down, so it's going to be on a dash. This one's going up, so it's going to be on a wedge. This one's down and on a dash, up and on a wedge, down and on a dash and up and on a wedge. And so that is it for step number 2, and in step number 3, all we need to do is fill in the hydrogens on the nitrogen atoms, so essentially just drawing in hydrogens on all of these nitrogen atoms shown here, and we need to draw in the R groups for each of the amino acid residues. And so the first amino acid residue that we have is 'a', and 'a' is for alanine, and just like 'a' is the first letter of the alphabet and that's easy to remember, alanine's r group is also easy to remember because it's literally just a methyl group or a CH three group. Now, the next one that we have is I, and I is for isoleucine, which is an isomer of Leucine, meaning it has the same chemical atoms, but a different arrangement of those chemical atoms. But that arrangement comes from valine and really it's a isoleucine is a lopsided valine. And so all we need to do is draw valine. So we know valine is literally just alanine with a v shape with these 2 methyl groups, and then to draw isoleucine, we just need to make valine lopsided. So there you go, and that is isoleucine structure. Now moving on, what we have is m and m is for methionine and methionine has a methyl thiol group and it its r group literally looks like an m. So the way that it works is it has a carbon going down and then coming up and then at this point over here, it has a methyl thiol group, so it has a sulfur and it has a methyl group coming off. So, essentially this is the methyl thiol group and it makes this m looking shape like that, a sideways m looking shape. And so that is Methionine structure where, just to be clear here, it has a carbon, right there, a carbon here, and a carbon over here. And so that's it for methionine, so we can move on to our next amino acid here which is the h and the h is for histidine. And histidine's r group, we know is alanine with a 5 membered ring coming off of it, and so it has features of a horse. And so essentially, all we need to do is draw alanine here, so we know alanine is going to be CH 3, but we know that the number of hydrogens are going to change for histidine, it's going to end being 2, and then it's gonna have a 5 membered ring branching off of it. So our 5 membered ring is gonna look like this. Great. So there's our 5 membered ring. And then we know that because, histidine's histidine's one letter code has these two parallel lines in it in the h, that reminds us that there's going to be 2 nitrogens in the r group and 2 double bonds, and the double bonds really help to make histidine's r group look like a sideways horse. And so here are the back legs with the double bond and here are the front legs with the double bond, and we know that the nitrogen here is going to be on the neck part over here, and it's going to have a hydrogen branching off like so, to make this nitrogen have a positive charge. And then we can even draw a little tail coming off the backside of this little horse here, so it kinda looks like a little horse with back legs, front legs, a nitrogen as the head right here, and again, it has the hydrogen tail coming off the back. So that's kind of like what we're looking at right there. And so, the next step is to figure out where does this second Nitrogen go. And so, we need to remember that the horse is not stepping on the second Nitrogen. So, the Nitrogen can't go here because the horse would be stepping on it, and the Nitrogen can't go here because the horse would be stepping on it. So, the only place the Nitrogen can go is over here. And so that is it for histidines' R group. Now again, next what we have is I and we already did I. I is isoleucine, so it's literally just a lopsided valine. So all we need to do is draw valine with the v shape like this and then, essentially coming off of this carbon here and then make it lopsided and that is isoleucine. And then next what we have is g and g is for glycine and glycines, r group literally just glides right on through because its r group is so small and so it's literally just a single hydrogen atom and that is it for glycine's r group. And then last but not least, what we have is histidine again, h. So all we need to do is redraw the same exact structure over here. So we have essentially, alanine with a 5 member ring, so c h 2, and then we know that there's gonna be a 5 membered ring, so 1, 2, 3, 4, 5. And then again because we have these 2 parallel lines like so, that reminds us that there's gonna be 2 double bonds and 2 nitrogen atoms. And so we know that we're gonna have back legs with with a double bond, so let's get that a little closer, back legs with a double bond, and front legs with a double bond. And we know that the nitrogen atom is going to be right here as the neck, and there's going to be hydrogen coming off like so, to make this nitrogen have a positive charge. And then coming off the back, there's going to be a hydrogen. And then we need to figure out that the other nitrogen, has to go at this position over here since the horse cannot be stepping on the second nitrogen. And so that is it for histidine structure and this concludes our peptide for aim high here. So we have indeed aimed high, and that concludes this practice problem. So I'll see you guys in our next video.

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Aim high and draw the following peptide: A-I-M-H-I-G-H.

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