Myoglobin is a protein containing 153 amino acids. Approximately half of the amino acids in myoglobin have polar side chains.
b. Where would you expect the nonpolar side chains to be?

Question

Myoglobin is a protein containing 153 amino acids. Approximately half of the amino acids in myoglobin have polar side chains.

b. Where would you expect the nonpolar side chains to be?

Accepted Answer

All right. Hello everyone. So this question says in a membrane protein composed of 400 amino acids, approximately 70% are nonpolar considering its location in the hydrophobic core of the cell membrane. Where would these nonpolar amino acids most likely be positioned in the membrane proteins? Tertiary structure option A says exposed on the outer surface of the membrane be is evenly distributed throughout the protein C says near the aqueous environment outside the membrane. And D says within the hydrophobic core of the membrane. So first let's talk about the location of a cell membrane or the structure I should say because recall that a cell membrane is composed of a lipid bilayer, right. So here on the outside, I'm drawing these circles that represent the polar ends of the fatty acids that make up the bilayer. And so in between them, their hydrophobic tail are combining in the center to create that hydrophobic core. And so here we see a very clear difference in polarity, the outer parts of the membrane interact with the polar environment outside of it. Whereas the nonpolar portions are making up the inside. And so here our theoretical protein is going to be located strictly within, let me actually change colors. It's going to be located strictly within this hydrophobic layer. So it's going to be interacting with the nonpolar fatty acid tails. So now it makes sense to say then that the properties of a protein's tertiary structure should allow it to mix well with its environment and tertiary structure. Just so we're clear is describing interactions between amino acid side chains. These amino acid side chains can be characterized in different ways depending on, for example, their polarity. So multiple different interactions are possible. And so going back to the perspective of the protein, the environment surrounding the protein is nonpolar. This means that nonpolar amino acids within the protein should be able to interact with its environment to allow for that protein to mix well with its environment. So therefore, what happened here is a very characteristic pattern of folding. So in this case, we have the polar amino acids within this protein trying their best to avoid interacting with the nonpolar environment. So they're going to be found more towards the center of the protein. Whereas the nonpolar amino acids are going to make up the outer portion. So they interact with the nonpolar environment because like dissolves like and it has the added benefit of protecting the polar amino acids inside. So here we've arrived at our final answer. It's going to be option d the multiple choice because these nonpolar amino acids are going to be found within the hydrophobic core of the membrane and there you have it. So with that being said, thank you so very much for watching. And I hope you found this helpful.

Myoglobin is a protein containing 153 amino acids. Approximately half of the amino acids in myoglobin have polar side chains.
b. Where would you expect the nonpolar side chains to be?

Verified video answer for a similar problem:

Key Concepts

Protein Structure

Polarity of Amino Acids

Hydrophobic Effect

Myoglobin is a protein containing 153 amino acids. Approximately half of the amino acids in myoglobin have polar side chains.b. Where would you expect the nonpolar side chains to be?

Verified video answer for a similar problem:

Key Concepts

Protein Structure

Polarity of Amino Acids

Hydrophobic Effect

Myoglobin is a protein containing 153 amino acids. Approximately half of the amino acids in myoglobin have polar side chains.
b. Where would you expect the nonpolar side chains to be?