Illustrated Glossary of Organic Chemistry

Tertiary structure: The three-dimensional structure of a biopolymer, as defined by the spatial coordinates of all the atoms. In a protein, tertiary structure is controlled by disulfide bridges and folding in response to environment. The tertiary structure of DNA is the supercoil.


Disulfide bridge

Amino acid side chain orientation Polar environment
(e.g., water)
Nonpolar environment
(e.g., cell membrane core)
Hydrophilic side chains
point outwards
point inwards
Hydrophobic side chains
point inwards
point outwards


DNA tertiary structure is the supercoil.