Which level of protein structure is characterized by α-helices and β-pleated sheets stabilized exclusively by hydrogen bonds along the polypeptide backbone?
Answer and explanation
Correct answer: B. Secondary structure
- Step 1: Differentiate the four organizational tiers of protein architecture.
- Step 2: Secondary structure consists of localized repetitive spatial arrangements (-helices, -pleated sheets) stabilized by hydrogen bonding between peptide backbone carbonyl oxygens and amide hydrogens.
Answer
Secondary structure.
Why not the others: Primary structure is the covalent amino acid sequence; tertiary structure is the 3D folding driven by R-group interactions; quaternary structure involves multi-subunit complexes.
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