What kind of bond would you expect between the side chains of the following amino acids?
b. Alanine and leucine

Question

What kind of bond would you expect between the side chains of the following amino acids?

b. Alanine and leucine

Accepted Answer

Alright. Hi, everyone. So this question is asking us to identify the type of molecular interactions or bonds formed between the side chains of the amino acids. Methionine and Valley. Option A says hydrogen bonding. Option B says ionic interactions. Option C says hydrophobic interactions and option D says disulfide bridge. So for the sake of this question, we do have to recall what the structures of methane and Veen happened to be. But before we do that, I wanna actually go ahead and go through each of the answer choices and just recall what each of them describe starting off with hydrogen bonding or H bonding. For option A now recall that H bonding is a type of intermolecular interaction where hydrogen must be connected to a highly electron element. Now, to be more specific, these can or these include sorry, oxygen, nitrogen and fluorine. So, amino acids, for example, that contain hydroxy or oh groups and amino or, and H two groups are capable of bonding ionic interactions or Option B here on the other hand, are interactions between charged start change of these amino acids. So for example, one amino acid that has a negative charge on the side chain interacts with another amino acid that has a positive charge on its side chain. Now, hydrophobic interactions for option C take place between amino acids that have nonpolar side chains and these interactions are due to the London dispersion forces that are primarily seen in nonpolar compounds. Now, last but not least is the disulfide bridge. Now of the four answer choices provided, recall that the disulfide bridge is the only covalent bond described here because a disulfide bridge occurs between two residues of cysteine. And recall that cystine has a thiol or sh group at the very end of the side chain itself, right? So these two thiol groups combined to create a covalent bond in between both sulfur atoms. Hence the term die sulfide, you had two Sulfurs connecting together. Now, because of this, I can actually go ahead and eliminate option d in the multiple choice because neither of the amino acids described here are cysteine, right. So disulfide bridge, a disulfide bridge is not possible. So now we can go ahead and talk about what these amino acids actually look like. So first, let me scroll down recall that all amino acids have the same general formula to them. We have an alpha carbon in the very center of the structure connecting to an amino group or an NH three positive. When it's ionized, we have a carboxylic acid group that has a negative charge when ionized, we have one hydrogen and we have an R group or the side chain depending on the amino acid. So, what I'm going to do first is just go ahead and draw out this backbone twice because the general structure is the same or both methane and veiling. And I'm actually going to space them out a bit more. So first, what I'm going to draw is methionine, abbreviated as met on the left side and vain or VA L on the right side, recall that the side chain of methane involve two carbons stemming from the alpha carbon in the center, followed by one sulfur atom and another methyl carbon. So essentially, right, the sulfur atom is in between two carbon atoms of the side chain. Now they lead on the other hand, has a side chain that looks like an isopropyl group or is an isopropyl group, right? So, branching off of the alpha carbon, we have a two carbon chain with an additional methyl group or ch three connecting to the carbon of the side chain that is directly connecting to the alpha carbon. This creates an isopropyl group that looks something like a V or A Y depending on how you look at it. But now that we've gone ahead and drawn these amino acids, I want to go ahead and talk about their side chains starting off with methane. Now, methane is notable because it has a bond between sulfur and two carbon atoms, but recall that there is actually no significant energy or electron negativity difference between carbon and sulfur. So what that means is that there isn't actually a dipole moment in between these two atoms, electrons in between them are being shared relatively evenly because they have similar electron negativities. So, Methionine has a nonpolar sight chain and so does Valley, right? Because the chain of vine is simply a hydrocarbon or an all kill group and there is no significant energy difference. Why do I keep saying energy? I mean, electron negativity, there is no significant electron negativity difference between carbon and hydrogen. So all kill groups or hydrocarbon side chains are also nonpolar. So there you have it right? Because both amino acids provided here have nonpolar side chains, they're primarily going to participate in hydrophobic interactions. Meaning our answer is option C and with that being said, thank you so very much for watching and I hope you found this helpful.

What kind of bond would you expect between the side chains of the following amino acids?
b. Alanine and leucine

Verified video answer for a similar problem:

Key Concepts

Hydrophobic Interactions

Amino Acid Side Chains

Protein Structure

What kind of bond would you expect between the side chains of the following amino acids?b. Alanine and leucine

Verified video answer for a similar problem:

Key Concepts

Hydrophobic Interactions

Amino Acid Side Chains

Protein Structure

What kind of bond would you expect between the side chains of the following amino acids?
b. Alanine and leucine