They provide tensile strength and elasticity to the matrices supporting body cells.
Collagens occur in everything from sponges to vertebrates.
In vertebrates the collagens of tendons, cartilage and bone make up about half the total body proteins by weight. Collagen Structure Collagens are a unique group of predominantly insoluble glycoproteins with a high content of glycine. Almost all the carbohydrate part is glucose and galactose in short 2-unit chains attached to the protein part. Individual collagen molecules are linear structures made of 3 polypeptide -chains in a shallow left handed helix. The triple helix makes the fibrous nature of collagen possible.