Why Should the Core of Most Globular and Membrane Proteins

Multiple Choice

Why should the core of most globular and membrane proteins consist almost entirely of α-helix and β-sheets?

A) Hydrogen bonded structures must be kept away from water solvent.
B) Highly polar N−H and C=O moieties of the peptide backbone must be neutralized in the hydrophobic core of the protein.
C) Hydrogen bonding only occurs in the core of proteins.
D) Trapped water stabilizes the helix and sheet structures.
E) None are true.