Quaternary Structure

Complexes of 2 or more polypeptide chains held together by noncovalent forces (usually) but in precise ratios and with a precise 3-D configuration.

The noncovalent association of a molecule of beta-2 microglobulin with the heavy chain of each class I histocompatibility molecule is an example.

Compare:

Primary Structure
Secondary Structure
Tertiary Structure

 

21 July 2010