Proteins occasionally take detours to off pathway species. These motifs do not typically fold independently. They often serve important functions. A single polypeptide chain can fold into multiple domains. Often each domain possesses its own function.
Many proteins possess more than one polypeptide chain.
Often the subunits in an oligomeric proteins are arranged in a highly symmetrical manner. You are expected to know two types of Symmetry 1. Dihedral Symmetry-An oligomeric protein is said to possess dihedral symmetry if in addition to one C 2 axis it possesses a second cyclic axis of symmetry. For example, if a protein has 2 C 2 axes it possesses D 2 symmetry. D 3 symmetry.