In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?
A) in the interior of the folded protein, away from water
B) on the exterior surface of the protein, interacting with water
C) in the transmembrane portion interacting with lipid fatty acid chains
D) in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains
E) anywhere in the protein, with equal probability

Question

Quizplus · Accepted Answer

Hydrophobic amino acids such as valine preferentially reside in hydrophobic environments and thus can be found in the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains. They would not be found on the exterior surface of the protein interacting with water, as they would not energetically favor the interaction with polar water molecules. Additionally, while amino acids like valine could technically be found anywhere in the protein, their placement within the folded structure would be dictated by their hydrophobicity and interactions with the surrounding environment.

In a Normal Cellular Protein, Where Would You Expect to Find