hemoglobine

In the case of hemoglobine of the blood, four polypeptide chains, all of them already with a tertiary structure, are joined to form one big entity: the quaternary structure.

The forces that make the formation of secondary and tertiary structures possible are:
  1. Hydrogen bridges
  2. vanderWaals forces
  3. dipolar forces
  4. Sulfur bridges (Cisteíne)