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Chemistry

Structure and Properties of Amino Acid Side Chains

Quick fact

A single amino acid side chain swap in hemoglobin — changing a charged glutamate to a hydrophobic valine — causes sickle cell disease. One side chain can reshape an entire protein.

Why this is interesting

All proteins are built from just 20 amino acids, yet they fold into astonishingly diverse shapes — the secret lies entirely in the side chains. How can such tiny differences create everything from muscle fibers to antibodies?