Concept:Proteins that consist of multiple distinct polypeptide subunits aggregated together exhibit the highest level of protein structure.
Formula:$$ \alpha_2\beta_2 $$
Solution:- Hemoglobin is composed of four individual polypeptide chains (two \( \alpha \)-globins and two \( \beta \)-globins in adults).
- These four separate subunits bind together via non-covalent interactions to form a single functional, multimeric protein complex.
- This aggregation of multiple independent polypeptide chains constitutes a quaternary structure.
Why other options are incorrect:While hemoglobin
contains primary, secondary, and tertiary structures within its individual subunits, the overarching functional structure of the complete, native protein is quaternary.
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