Collagens collagen triple helix

This gives an important hint at what kind of model peptides are synthesized to obtain detailed information about the thermodynamics and kinetics of the collagen triple-helix formation. A first success was already achieved by synthesizing peptides of the following general structure37 ... 

Engel J, Bachinger H-P (2005) Structure, Stability and Folding of the Collagen Triple Helix. 247 7-33... 

Steinmann, B., Bruckner, P. and Superti-Furga, A. (1991) Cyclosporin A slows collagen triple-helix formation in vivo indirect evidence for a physiological role of peptidyl prolyl cis-trans isomer use. Journal ofBiological Chemistry 266,1299-1303. 

Brodsky, B. and Ramshaw, J.A.M. (1997) The collagen triple-helix structure. Matrix Biology, 15, 545-549. 

Atomic Structures of the Collagen Triple Helix and Collagen Trimerization Domains 510... 

Figure 1 The collagen triple helix, (a) Colored by element C (green), O (red), N (blue), S (yellow) (b) colored by chains and (c) colored by Gly (red), Xaa (yellow), and Yaa (white) positions. The modeis were buiit using PyMOL with the type iii coiiagen model peptide (PDB accession number 3DMW). Glycine residues in every third position are located on the inside of the triple helix. Each chain is staggered by one residue to accommodate the Gly in the center of the triple helix.

Figure 16 Interchain hydrogen bond network in collagen triple helix. The figure was generated using the UCSF Chimera package and coordinates from PDB structure 1QSU.

The availability of high-resolution structures of peptides EKG, T3-785, IBP, and G991-G1032, which include residues other than Pro and Hyp in the X and Y positions, offers the opportunity to investigate the conformation and interactions of side chains from residues typically found within the collagen triple helix. In the peptide with an EKG tripeptide sequence, the Lys and Glu residues did not form direct intermolecular or intramolecular ion pairs, even though such pairs are sterically feasible. ... 

Despite the requirement ofNC domains for correct oligomerization of the collagen triple helix, the NC domain structures are divergent among all collagens. The structure of the NCI domain of type IV collagen " is... 

Another type of helix occurs in the collagens, which are important constituents of the con-nectivetissue matrix (see pp. 70, 344). The collagen helix is left-handed, and with a pitch of 0.96 nm and 3.3 residues per turn, it is steeper than the a-helix. In contrast to the a-helix, H bonds are not possible within the collagen helix. However, the conformation is stabilized by the association of three helices to form a righthanded collagen triple helix (see p. 70). 

Kar K, Amin P, Bryan MA, Persikov AV, Mohs A, Wang Y-H, Brodsky B. Self-association of collagen triple helix peptides into higher order structures. J Biol Chem 2006 281 33283-33290. 

Each of the three strands of the collagen triple helix is based upon the poly(Pro)II helix. Numerous studies of peptides capable of triple helix formation have been performed, and these have been reviewed 149 The CD of the collagen triple helix1146 is qualitatively like that of the poly(Pro)II, but the position of the maximum depends on the content of secondary vs tertiary peptide bonds. In natural collagen, the positive band is at about 220 nm and the negative band at 197 nm. 

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