Amino Acids Likely Found in Protein Interiors

Subject : Biology

Question:

Select the amino acids that are most likely to be found in the interior of a protein.

A. Glutamic acid

B. Leucine

C. Lysine

D. Valine

E. Phenylalanine

Expert Verified Solution:

The amino acids most likely to be found in the interior of a protein are Leucine, Valine, and Phenylalanine.

Here’s why:

Leucine: This is a non-polar, hydrophobic amino acid, which means it tends to avoid water. In proteins, hydrophobic amino acids are often found in the interior, away from the aqueous environment, where they stabilize the protein’s structure by forming a hydrophobic core.

Valine: Similar to leucine, valine is a non-polar, hydrophobic amino acid. It also prefers to be in the interior of proteins, contributing to the formation of a hydrophobic core that helps stabilize the protein’s three-dimensional structure.

Phenylalanine: This amino acid is also non-polar and hydrophobic, with a bulky aromatic side chain. It is typically found in the interior of proteins, where it can participate in hydrophobic interactions that help maintain the protein’s stability and shape.

In contrast:

Glutamic acid is a polar, negatively charged amino acid that is more likely to be found on the exterior of a protein, interacting with the aqueous environment or other polar molecules.

Lysine is a polar, positively charged amino acid and, like glutamic acid, is more commonly found on the exterior of proteins, where it can interact with the aqueous environment or participate in various biochemical interactions.

These properties of amino acids are crucial for understanding protein folding and stability, as the distribution of hydrophobic and hydrophilic residues helps determine a protein’s final structure and function.