Primary Structure of the Helical Domain of Porcine Collagen X

The entire primary structure of the collagen X helical region is presented, including identification of the extensive post-ribosomal modifications by amino acid sequencing and mass spectrometry. As in collagen I, a single residue of 3-hydroxyproline was identified, but for collagen X this was located near the N-terminal end of the helix. Lysine residues in collagen X are extensively hydroxylated/glycosylated: at least 11 sites were localized and shown to be fully glycosylated, exclusively as glucosyl-galactosyl derivatives. The lysine-derived crosslinks, dihydroxylysinonorleucine and hydroxylysinonorleucine, were shown to be present in a 3:2 molar ratio primarily within the C-terminal portion of the helix.