Definition of Quaternary Structure



Quaternary structure of a protein is formed by the interactions between the multiple polypeptide chains. The interactions that make up the quaternary structure include the hydrogen bonding, dipole-dipole forces, London dispersion forces, ionic bonding, hydrophobic interactions and disulphide bonds.

 


Example of Quaternary Structure:

The examples of protein molecules that exhibit the quaternary structure include hemoglobin and DNA polymerase. The hemoglobin is responsible for transporting oxygen to the body tissues and organs. It is made up of four polypeptide chains i.e. two α and two β polypeptides. The DNA polymerase is composed of ten polypeptides and it serves the role of synthesizing the new strands of DNA (DNA replication) in 5’ to 3’ direction.

 


Quaternary Structure


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