Collagen molecules arrangement

Figure 29-10 Schematic diagram of collagen molecules in a fibril so arranged as to give the 640-A spacing visible in electron micrographs...

Fig. 5-17 A possible model for the three-dimensional packing arrangement of collagen molecules in a pentamicrofibril.

Figure 4 Elementary unit cell of the periodic arrangement of collagen molecules within a fibril (rat tail tendon). The alpha-carbons are rendered as line spheroids showing the conformation of the D-staggered collagen segments. Each color corresponds to another (triple-helical) molecule. The direction indicated by c corresponds to the axial direction of the fibril. Its length has been compressed 5 times compared to the other directions. Reproduced from Orgel, J. P. R. 0. Irving, T. C. Miller, A. Wess, T. J. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 9001-9005. Copyright (2006) National Academy of Sciences, U.S.A.

The triple-helical collagen molecules assemble into fibrils, where the single molecules are parallel to each other and connected by intermolecular cross-links. A generally accepted model about the arrangement of the collagen molecules was first proposed by Petruska and Hodge. This is described in detail in Section 9.03.2.2 as well as the mineralization of the collagen fibrils in Section 9.03.2.3. 

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