Correct option is D
The correct answer is: (4) Protruding regions on the surface are composed predominantly of hydrophilic amino acids.
Explanation:
B cell epitopes are the regions on the surface of a protein that interact with the antibodies produced by B cells. These epitopes tend to be exposed on the surface of the protein, where they are accessible to the immune system. The regions that form epitopes are typically composed of hydrophilic amino acids, as these regions need to be exposed to the aqueous environment for proper recognition by antibodies. Hydrophilic residues are more likely to be on the surface, while hydrophobic residues are typically buried inside the protein, stabilizing the protein’s structure by avoiding the aqueous environment.
Information Booster:
Hydrophobic amino acids are typically found in the interior of proteins, where they help stabilize the protein's structure by avoiding water.
Hydrophilic amino acids are commonly found on the surface of proteins, where they interact with the surrounding aqueous environment and facilitate the interaction with antibodies.
B cell epitopes must be exposed on the surface of a protein so that they can be recognized by B cell receptors and antibodies, which are often hydrophilic.
This hydrophilic nature of epitopes makes them more accessible for the immune system to identify and bind, promoting immune recognition.
Additional Knowledge:
Hydrophobic amino acids (option 1) are typically found in the interior of proteins, where they avoid the aqueous environment and help stabilize the folded structure of the protein.
Hydrophilic amino acids (option 2) can be in the interior, but they are more likely to be exposed on the surface where they interact with the solvent or immune cells.
Hydrophobic regions on the surface (option 3) would be unusual for B cell epitopes, as such regions are not easily accessible to antibodies and are more likely to be buried within the protein's core for stability.
