Fill-in the missing R-groups for the following peptide from me...

Question

Fill-in the missing R-groups for the following peptide from memory: D-I-F-C-R-Q.

Diagram of a peptide chain with missing R-groups for amino acids D-I-F-C-R-Q.

Accepted Answer

So this practice problem wants us to fill in the missing r groups for the following peptide from memory, and the peptide is d I f crq. And so each of these letters is the one letter symbol for each of, the corresponding amino acids. And so in order to solve this problem, we're gonna need to remember our mnemonics for memorizing the amino acids, and those are GAV limp, fat young whipper snappers or FYW, Santa's team crafts new quilts, and then dragons eat knights riding horses. And so the first one that we have is d, and d here, it falls under the dragons eat knights riding horses. And dragons eat is shaded green because those are the negatively charged acidic amino acids. And recall that each of these first letters in, the mnemonics, they all use alanine as a starter. So aspartic acid or d is gonna use alanine, and so all we need to do is put in alanine. And we know the number of hydrogens are gonna change, it's gonna end up being 2. And then we say, okay, well, aspartic acid is an acid. So it's an acid because of the presence of carboxylic acids. And so, we know that, aspartic acid can donate a hydrogen and become aspartate, so let's draw aspartate here, the charged one. And so we know that it's gonna have a carboxyl group branching off of the the, alanine here, so it's just gonna be alanine with a carboxyl group or carboxyl group, and that's it. That is aspartic acid structure. The next that we have is I, and I is for isoleucine and so isoleucine is found up here. And remember that isoleucine is an isomer of leucine and, remember isomers are just, you have the same atoms and types of atoms, but a different arrangement of those atoms. And the arrangement actually comes from valine, and so isoleucine is just a lop sided valine. And so all we need to do is, for our second amino acid up here, is to draw in valine. So here's our valine, upside down, and then all we need to do is make it lopsided. Perfect. That's isoleucine. Now, isoleucine is done. We can do f f stands for phenylalanine. And here we have phenylalanine and remember phenylalanine's name is literally telling you what its R group is. It's alanine with a phenyl group. So all we need to do is put in our our alanine. Let's do a different color here. So we can do our alanine, so we know the hydrogens are gonna change, it's gonna end up being 2, and then we say it's okay, it's alanine with a phenyl group and a phenyl group is just a branching benzene ring. And so that's it, that's phenylalanine. So now that we have f, the next is c, and c stands for cysteine and cysteine is found right here. And so cystine, is really sounds like the Sistine Chapel. And Sistine spends a lot of quiet time in the Sistine Chapel, which is a church. And so anytime somebody makes a noise, cystine is always like shh. And so all cystine is is alanine with a sh group or an s h group. So all we need to do is put in alanine, so just a c h, and we know the hydrogens are gonna end up changing, it's gonna end up being 2. And so it's alanine with an SH group or SH group, and the SH group is a sulfhydro found right here. And so when arginine is found right here. And so with arginine, remember that it has a mixture of both the the lysine, and the histidine. It has a mixture of both this, knight's sword and the horse. And so, because it has parts of the knight's sword, you wanna to think, okay, with with an r, how many pointy ends are there that I could try to poke somebody with? And we know that there's 1, 2, 3. So that tells us there's a 3 carbon start to our chain. So we're gonna put in our 3 carbons, so we'll have CH2, CH2, CH2. Perfect. So there's our 3 carbon And then just like there's a 3 carbon start, we know that there's going just like there's a 3 pointy ends in our carbon, we know that there's gotta be a triangular, so three parts. There's gotta be a triangular nitrogen structure. And the way that works is it's an n, a c, and n, and then, the c is double bonded to another nitrogen. And then, at this point, all you need to do is fill in the hydrogens. So this one's gonna have 1, this one will have 2, this one will also have 2, and it's this nitrogen here that's a double bonnet that's gonna have that positive charge on it. And so that's it. That's the structure of arginine. And then last, now that we have arginine, is, q, and q stands for glutamine or cutamine. And, glutamine has that GLUT in it, and so glutamine is found, over here. And so glutamine structure, remember, branches off of a spargene structure. So it's literally just a spargene with an extra CH 2 in it. And so all we need to do to draw its structure is to just put in a c h 2, an extra c h 2, and then to draw in that amide or that c double bond o with the NH 2 on it. And so that's it for a glutamine structure, and this completes this practice problem. So I'll see you guys in our next video.

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Fill-in the missing R-groups for the following peptide from memory: D-I-F-C-R-Q.

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