Detailed Explanation
The overall three-dimensional shape of a single polypeptide chain, determined by long-range interactions between amino acid R groups. While secondary structure describes local patterns (helices, sheets), tertiary structure describes the global fold — how all the secondary structure elements pack together in space.
Stabilizing forces include hydrophobic interactions (nonpolar residues buried in the core), disulfide bonds (Cys–Cys), salt bridges (Lys/Arg with Asp/Glu), and hydrogen bonds between side chains. Tertiary structure determines biological function: the shape of the active site, the receptor-binding surface, and the location of regulatory sites. Tertiary structure is determined experimentally by X-ray crystallography, NMR spectroscopy, and cryo-electron microscopy, or predicted computationally by AlphaFold.
Key Facts
- The overall three-dimensional shape of a single polypeptide chain, determined by long-range interactions between amino acid R groups.
- While secondary structure describes local patterns (helices, sheets), tertiary structure describes the global fold — how all the secondary structure elements pack together in space.
- Stabilizing forces include hydrophobic interactions (nonpolar residues buried in the core), disulfide bonds (Cys–Cys), salt bridges (Lys/Arg with Asp/Glu), and hydrogen bonds between side chains.
- Tertiary structure determines biological function: the shape of the active site, the receptor-binding surface, and the location of regulatory sites.
- Tertiary structure is determined experimentally by X-ray crystallography, NMR spectroscopy, and cryo-electron microscopy, or predicted computationally by AlphaFold.
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