Collagen fibril, functions

The collagen molecules formed by removal of the propeptides spontaneously assemble into fibrils. At this stage, the fibrils are still immature and lack tensile strength, which is acquired by cross-linking. The initial step in cross-link formation is the oxidative deamination of a-amino groups in certain lysyl and hydroxyly-syl residues catalyzed by lysyl oxidase. The enzyme is a copper-dependent (probably cupric) protein, and the reaction requires molecular oxygen and pyridoxal phosphate for full activity. Only native collagen fibrils function as substrates. 

Col Hal null mice have fibril diameter abnormalities in the early postnatal stage but the adult showed no significant differences. Type XIV collagen might function early in development regulating the entry of fibril intermediates into lateral fibril growth. ... 

Inspiration for development of dynamic supramolecular polymers comes from living systems, where enzyme-controlled formation and degradation of collagen fibrils, actin filaments and microtubules underlie vital cellular functions such as motility, differentiation, division, etc. (Fig. 1). 

The purpose of this Chapter is to review the major features of collagen fibrils and to demonstrate the current state of understanding the way collagen fibrils produce functional materials. 

Parry, D. A. D., Barnes, G. R. G., and Craig, A. S. (1978). A comparison of the size distribution of collagen fibrils in connective tissues as a function of age and a possible relationship between fibril size distribution and mechanical properties. Proc. Roy. Soc. Lond. B. 203, 305-321. 

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