Collagen triple helix stability

Berisio, R., Granata, V., Vitagliano, L., and Zagari, A. (2004). Imino acids and collagen triple helix stability Characterization of collagen-like peptides containing Hyp-Hyp-Gly sequence repeats./. Am. Chem. Soc. 126, 11402-11403. 

Persikov, A. V., Ramshaw, J. A. M., Kirkpatrick, A., and Brodsky, B. (2005). Electrostatic interactions involving lysine make major contributions to collagen triple-helix stability. Biochemistry 44, 1414—1422. 

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

Prolyl 4-hydroxylation is the most abundant posttranslational modification of collagens. 4-Hydroxylation of proline residues increases the stability of the triple helix and is a key element in the folding of the collagen triple helix. " In vertebrates, almost all the Yaa position prolines of the Gly-Xaa-Yaa repeat are modified to 4(I( )-hydroxylproline by the enzyme P4H (EC 1.14.11.2), a member of Fe(II)- and 2-oxoglutarate-dependent dioxygenases. This enzyme is an 0 2/ b2-type heterotetramer in which the / subunit is PDI (EC 5.3.4.1), which is a ubiquitous disulfide bond catalyst. The P4H a subunit needs the 13 subunit for solubility however, the 13 subunit, PDI, is soluble by itself and is present in excess in the ER. Three isoforms of the a subunit have been identified and shown to combine with PDI to form [a(I)]2/ 2) [< (II)]2/32> or [a(III)]2/32 tetramers, called the type... 

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). 

Bachinger, H. P., and Davis, J. M. (1991). Sequence specific thermal stability of the collagen triple-helix. Int. J. Biol. Macromol. 13, 152-156. 

Persikov, A. V., Pillitteri, R. J., Amin, P., Schwarze, U., Byers, P. H., and Brodsky, B. (2004). Stability related bias in residues replacing glycines within the collagen triple helix (Gly-Xaa-Yaa) in inherited connective tissue disorders. Hum. Mut. 24, 330-337. 

Sakikabara, S., Inouye, K., Shudo, K., Kishida, Y., Kobayashi, Y., andProckop, D.J. (1973). Synthesis of (Pro-Hyp-Gly) n of defined molecular weights. Evidence for stabilization of collagen triple-helix by hydroxyproline. Biockim. Biphys. Acta 303, 198-202. 

Figure 2.21. Stabilization of collagen triple helix. The diagram shows hydrogen bonding between the amide hydrogen in position 4 on chain A and the carbonyl oxygen in position 2 on chain B. A second water-mediated hydrogen bond occurs when hydroxyproline is present in position 3 on chain A between the carbonyl oxygen in position 1 on chain A and the amide hydrogen in position 2 on chain B.

---