Type I collagen is a member of group I collagen (fibrillar forming collagen). Trimers of one alpha 2(I) and two alpha 1(I) chains. Forms the fibrils of tendon, ligaments and bones. In bones, the fibrils are mineralized with calcium hydroxyapatite. Prolines at the third position of the tripeptide repeating unit (G-X-Y) are hydroxylated in some or all of the chains. These protein fragments were extracted from fossils. The tryptic peptides required multiple purification steps in order to eliminate contaminants and to increase the concentration of peptidic material. Belongs to the fibrillar collagen family.