Structures collagen, models

Collagen-Model Peptides with Antiparallel Structure. 177... 

III. Molecular Structure Collagen and Collagen Model Peptides. 307... 

Figure 2.20. Models of collagen structure. (A) Model of three parallel left-handed helixes of collagen showing the location of Coc (C) for chains A, B, and C. Note all glycines are found in C-l position because this is the only amino acid residue that can be accommodated at the center of the triple helix. Later studies by Ramachan-dran and co-workers indicated that the three chains are wrapped around each other (B) in a right-handed superhelix. The axial rise per residue is 0.29 nm, and the axial displacement of different Coc atoms is shown in parentheses in angstroms.

M. H. Miller and H. A. Scheraga,/. Polym. Sci. Polym. Symp., No. 54,171 (1976). Calculation of the Structures of Collagen Models. Role of Interchain Interactions in Determining the Triple-Helical Coiled-Coil Conformation. I. Poly(glycyl-prolyl-prolyl). 

The fringed micelle picture is not particularly suitable for describing synthetic polymers crystallized from solution or melt. However, the fibrils of many natural substances, such as cellulose and proteins (collagen, silk), consist of bundles of macromolecules in a parallel alignment, compatible with the fringed micelle model. For synthetic polymers, however, it is more often found that they crystallize such that the macromolecules fold with an essentially constant length, leading to a lamellar-type crystallite structure (switchboard-model. Fig. 1.11). 

Suehiro, T., Kojima, C., Tsumura, S., Harada, A., and Kono, K. 2010. Higher order structure of short collagen model peptides attached to dendrimers and linear polymers. Biopolymers 93(7), 640-648. 

Fig. 29 Molecular structures of multi-branched self-assembling coUagen-models, and representation of the self-assembly process of the collagen models through triple-helix formation. (Adapted from [104])...

The detection of the collagen-like threefold symmetric polypeptides, polyglycine4 and polyproline5, was the first help to elucidate the collagen structure using a synthetic peptide model. 

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