Triple-helical collagen

This division into classes is also supported by a comparison of their specificities toward peptide substrates [15,18,19], their interaction with substrate-analogue inhibitors [20], their response to active site metal substitutions [21,22], and their mode of attack of triple helical collagens [23] (French, M.F., Bhown, A. and Van Wart, H.E., unpublished data). 

Extracellular cleavage of procollagen molecules After their release, the procollagen molecules are cleaved by N- and C-pro-collagen peptidases, which remove the terminal propeptides, releasing triple-helical collagen molecules. 

The classic example of a Type B repeat is that presented by the o-chains in collagen. Three such chains aggregate to form a triple-helical collagen molecule, but they can only do so if glycine is positioned in every third residue of the sequence (Hulmes, 1992). This is because glycine is located internally and, due to its size, is the only residue that can fit stereochemi-cally into the space available. In the Type I collagen Q-chain, the repeat occurs 338 times contiguously. 

Chung, L., Dinakarpandian, D., Yoshida, N., Lauer-Fields, J. L., Fields, G. B., Visse, R., and Nagase, H. (2004). Collagenase unwinds triple-helical collagen prior to peptide bond hydrolysis. EMBO J. 23, 3020-3030. 

Fields, G. B., and Prockop, D. J. (1996). Perspectives on the synthesis and application of triple-helical, collagen-model peptides. Biopolymers 40, 345-357. 

Knight, C. G., Morton, L. F., Peachey, A. R., Tuckwell, D. S., Farndale, R. W., and Barnes, M. J. (2000). The collagen-binding A-domains of integrins 01/51 and < 2/51 recognize the same specific amino acid sequence, GFOGER, in native (triple-helical) collagens./. Biol. Chem. 275, 35-40. 

Perret, S., Merle, C., Bernocco, S., Berland, P., Garrone, R., Hulmes, D.J., Theisen, M., and Ruggiero, F. (2001). Unhydroxylated triple helical collagen I produced in transgenic plants provides new clues on the role of hydroxyproline in collagen folding and fibril formation. J. Biol. Chem. 276, 43693-43698. 

Simon-Lukasik, K. V., Persikov, A. V., Brodsky, B., Ramshaw, J. A., Laws, W. R., Ross, A., and Ludescher, R. D. (2003). Fluorescence determination of tryptophan side-chain accessibility and dynamics in triple-helical collagen-like peptides. Biophys. J. 84, 501-508. 

Paterlini, M. G., Nemethy, G., and Scheraga, H. A. (1995). The energy of formation of internal loops in triple-helical collagen polypeptides. Biopolymers 35, 607-619. 

Recombinant [oil (VIII) ] 3 and [a2(VIII)]s molecules form highly ordered supramolecular assemblies. These assemblies may be formed by four triple-helical collagen VIII molecules that come together to form a tetrahedron via the hydrophobic patches on their G-termini. It has also been suggested that these tetrahedral structures may further associate to form hexagonal lattices, with the N-terminals of individual molecules interacting with either the N-terminals or with the triple-helical portion of molecules in other tetrahedrons (Stephan et al., 2004). 

Metallo- protease collagenase (mammalian) cleaves a Gly-Leu or Gly-Ile bond in native triple helical collagen... 

Fig. 9. Effect of CsA on the rate of procollagen 1 triple helix formation in suspended chicken embryo tendon cells. The time course of procollagen 1 triple helix formation was monitored in a pulse-chase experiment by separation of protease-resistant al(l) and a2(I) chains by SDS-polyacrylamide gel electrophoresis. The fluorograms (upper panel) show the appearance of protease-resistant and hence triple-helical collagen I in the absence (—) or in the presence (-I-) of 5 fiM CsA. The kinetics are shown in the lower panel (O) no CsA ( ) 5 ixM CsA. Best fits are drawn according to the model of Bruckner and Eikenberry (1984). From Steinmann et al. (1991).

Kwak J, Capua AD, Locardi E, Goodman M. TREN (Tris(2-aminoethyl.amine) an effective scaffold for the assembly of triple helical collagen mimetic structures. J. Am. Chem. Soc. 2002 124 14085-14091. 

It is therefore necessary to distinguish betiveen inter- and uitramolecular cross-links. The latter are links between the individual chains of a triple helical collagen monomer whereas the former are links from one (iollagen monomer to another... 

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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