Consider the amino acids lysine, valine, and aspartate in an e...

Question

Consider the amino acids lysine, valine, and aspartate in an enzyme. State which of these amino acids have R groups that would:

c. form hydrogen bonds

Accepted Answer

All right. Hello everyone. So this question says, given the amino acids, a sntrptyr and VA L, which amino acids have side chains capable of hydrogen bonds, select all that apply. One is a SN two is TRP, three is Tyr and four is VA L. And so here we're also given four different answer, choices labeled A through D proposing different combinations of the four given amino acids. Now, speaking of amino acids recall that they can be abbreviated either using three letter or one letter abbreviations and these are standardized. So they only refer to one amino acid. For example, a SN is referring to asparagine TRP is referring to tryptophan or tryptophan Tyr is referring to tyrosine and VA L is referring to Valley. And so these different amino acids based on the properties of their side chains can be classified in different ways. For example, we can talk about polar neutral amino acids, we can talk about acidic or basic amino acids that would have a charge at physiological Ph and we also talk about nonpolar or hydrophobic amino acids. And so now the question is, how do you decide what side chains are capable of h bonding or hydrogen bonding. Well, first, we should recall what an age bond is right, recall that a hydrogen bond is an interaction between a hydrogen atom that's bound to an electron element abbreviated here as X for the sake of the example, and that hydrogen connecting to an electron atom is interacting with another electron atom. So let's use a more specific example of a hydroxy group interacting with a car bal. Now, the hydroxy group contains a hydrogen that's attached to an electron oxygen act, we can see a hydrogen bond between that oxygen and another electron oxygen atom. This time from the car bottle, this is an example of a hydrogen bond. So now let's go ahead and discuss each amino acid specifically and focus on the most important elements of their side chains starting off with asparagine. Now recall that asparagine has an amide functional group. So we have a car bono and that carbon carbon is attached to a nitrogen, right. So if we consider the structure, we can see that we have hydrogen atoms connecting to an electron nitrogen atom. In addition, we also have a car bottle oxygen that could also participate in a hydrogen bond. So asparagine can participate in bonding. It's a very strong participant of hydrogen bombing. So from here, we can talk about pyraz or excuse me, tryptophan is the second one. So let me go and order. So speaking of trip to Spain, right? Tryptophan is an example of an aromatic amino acid. But what's noteworthy here is that the ring structure of tryptophan does have a nitrogen atom embedded within it. This nitrogen can engage in hydrogen bonnets. Now, granted right, the bonding capacity of tryptophan ring nitrogen is limited compared to other amino acids that may have more polar side chains. But regardless tryptophan can participate in h bonding. So it's going to be correct here. So now we can talk about the third which is tyrosine, right tyrosine is another example of an aromatic amino acid. But this time it has a hydroxy group branching off of a benzene ring, hydroxy groups feature a hydrogen attached to an electron oxygen atom. And so the hydrogen can participate in h bonding but so can the oxygen. So the answer is yes for thyroxine as well. Last but not least we have number four which is veiling. Now vain if you recall is an example of a nonpolar amino acid with a hydrocarbon side chain, nonpolar amino acids, nonpolar side chains cannot participate in h bonding because h bonding is characteristic of polar combats. And so of the four amino acids numbers 12 and three do participate in h bonding, meaning C is the correct answer and there you have it. So with that being said, thank you so very much for watching. And I hope you found this helpful

Consider the amino acids lysine, valine, and aspartate in an enzyme. State which of these amino acids have R groups that would:
c. form hydrogen bonds

Key Concepts

Amino Acid Structure

Hydrogen Bonding

Polarity of R Groups

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