Bone formation
The regular staggered array of spaces among the ends of the tropocollagen molecules in a collagen ?berin the above figure are the nucleation sites for the deposition of a form of hydroxyapatite, calcium phosphate, in bone creation. Additional hydroxy- apatite is added until the nucleation sites grow and join with one another to form the mature bone structure.
Figure: Conversion of lysine to allysine by lysyl oxidase.