Molecular Structure and Functions of Collagen
This chapter looks at variables such as fibril diameter, orientation, tissue distribution, relative concentrations and packing of fibrils into larger volumes, and search for patterns which occur during development and aging. It presents an overview of the molecular structure and functions of collagen, its biosynthesis, and some factors which modulate fibrillogenesis, cross-linking, and turnover. Collagen fibers appear early during embryonic development at a time when structure differentiation begins to emerge. Collagen fibers, by virtue of altering their diameters and modality of packing, provide different tissues with very characteristic features which range from transparency to great tensile strength and from energy storage to heat dissipation. The thermodynamics of such a system involve changes in the state of the water molecules associated with the nonpolar regions of the collagen molecule. The synthesis of procollagen chains involves the translation of a specific messenger RNA on membrane-bound ribosomes similarly to secretory proteins, in general, and core protein of proteoglycans.