So Collagen is by far the most abundant protein found in our body. It is found mostly in the extracellular tissue in our connective tissue, such as, for example, bone. And what Collagen does is it gives our tissue its strength. So what is the structure of Collagen? Well, Collagen has a coronary structure, and one of the most abundant amino acids in Collagen is proline. Now, what Collagen does is it modifies the structure of proline by adding a hydroxyl group to produce hydroxyproline.