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 bones. 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 an ancient femur bone collected in Roseburgh, Oregon, USA. Belongs to the fibrillar collagen family.