What type of interaction would you expect between the side chains of each of the following pairs of amino acids in the tertiary structure of a protein?
b. alanine and valine

Verified step by step guidance

1. Identify the side chains of alanine and valine. Alanine has a methyl group (-CH3) as its side chain, while valine has an isopropyl group (-CH(CH3)2) as its side chain.
2. Recognize that both alanine and valine have nonpolar, hydrophobic side chains.
3. Understand that in the tertiary structure of a protein, nonpolar side chains tend to interact with each other through hydrophobic interactions.
4. Explain that these hydrophobic interactions help stabilize the protein structure by minimizing the exposure of nonpolar side chains to the aqueous environment.
5. Conclude that the interaction between the side chains of alanine and valine in the tertiary structure of a protein is primarily hydrophobic.

Key Concepts

Amino Acid Side Chains

Amino acids have unique side chains (R groups) that determine their chemical properties and interactions. The side chains can be polar, nonpolar, acidic, or basic, influencing how they interact with each other in a protein's tertiary structure. Understanding these properties is crucial for predicting interactions between specific amino acids.

Hydrophobic Interactions

Hydrophobic interactions occur when nonpolar side chains, such as those of alanine and valine, cluster together to avoid contact with water. This phenomenon is a key driving force in protein folding, as it helps stabilize the protein's three-dimensional structure by minimizing the exposure of hydrophobic regions to the aqueous environment.

Tertiary Structure of Proteins

The tertiary structure of a protein refers to its overall three-dimensional shape, formed by the folding and interactions of its amino acid side chains. This structure is critical for the protein's function, as it determines how the protein interacts with other molecules. The specific interactions between side chains, such as those between alanine and valine, play a significant role in stabilizing this structure.