How much do you know about collagen. Collagen is an abundant structural protein in all animals, which form molecular cables to strengthen the tendons and the resilient sheets that support the skins and internal organs of animals. Collagen basic structure made up of three polypeptide chains, three polypeptide chains coiled together to form a right-handed triple helix. And each polypeptide chain is characterized by the repeating structure of Glycine,proline,hydroxyproline.