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. Expressed in bone. 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 ancient bone material (PubMed:25799987, PubMed:31171860). The displayed protein fragments were extracted from an ancient caudal vertebra bone collected in Ultima Esperanza, Chile and around 13045 years old (PubMed:31171860). The tryptic peptides required multiple purification steps in order to eliminate contaminants and to increase the concentration of peptidic material (PubMed:25799987). Belongs to the fibrillar collagen family.