What chemical interaction is primarily responsible for stabilizing the alpha-helical secondary structure of proteins?
Answer and explanation
Correct answer: D. Hydrogen bonds between peptide backbone carbonyl oxygens (C=O) and amide hydrogens (N-H) four residues ahead
The alpha-helix is a right-handed coiled secondary structural motif stabilized by intrachain hydrogen bonds between the backbone carbonyl oxygen of residue n and the backbone amide N-H of residue n+4. Side chain interactions, hydrophobic forces, and disulfide bonds stabilize the tertiary and quaternary folds, not the secondary backbone architecture.
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