2CUO

Collagen model peptide (PRO-PRO-GLY)9

Summary for 2CUO

• Entry DOI: 10.2210/pdb2cuo/pdb
• Related: 1ITT
• Descriptor: COLLAGEN MODEL PEPTIDE (PRO-PRO-GLY)9 (2 entities in total)
• Functional Keywords: collagen model peptide, triple-helix, puckering, structural protein
• Total number of polymer chains: 6
• Total formula weight: 13677.28

Authors

Hongo, C.,Noguchi, K.,Okuyama, K.,Tanaka, Y.,Nishino, N. (deposition date: 2005-05-27, release date: 2005-06-14, Last modification date: 2023-10-25)

Primary citation

Hongo, C.,Noguchi, K.,Okuyama, K.,Tanaka, Y.,Nishino, N.
Repetitive interactions observed in the crystal structure of a collagen-model peptide, [(Pro-Pro-Gly)9]3
J.Biochem.(Tokyo), 138:135-144, 2005

PubMed Abstract: The crystal structure of a collagen-model peptide [(Pro-Pro-Gly)(9)](3) has been determined at 1.33 A resolution. Diffraction data were collected at 100 K using synchrotron radiation, which led to the first structural study of [(Pro-Pro-Gly)(n)](3) under cryogenic conditions. The crystals belong to the P2(1) space group with cell parameters of a = 25.95, b = 26.56, c = 80.14 Angstroms and beta = 90.0 degrees. The overall molecular conformation was consistent with the left-handed 7/2-helical model with an axial repeat of 20 A for native collagen. A total of 332 water molecules were found in an asymmetric unit. Proline residues in adjacent triple-helices exhibited three types of hydrophobic interactions. Furthermore, three types of hydrogen-bonding networks mediated by water molecules were observed between adjacent triple-helices. These hydrophobic interactions and hydrogen-bonding networks occurred at intervals of 20 Angstroms along the c-axis based on the previous sub-cell structures [(Pro-Pro-Gly)(n)](3) (n = 9, 10), which were also seen in the full-cell structure of [(Pro-Pro-Gly)(10)](3). Five proline residues at the Y position in the X-Y-Gly triplet were found in a down-puckering conformation, this being inconsistent with the recently proposed propensity-based hypothesis. These proline residues were forced to adopt opposing puckering because of the prevailing hydrophobic interaction between triple-helices compared with the Pro:Pro stacking interaction within a triple-helix.

PubMed: 16091587
DOI: 10.1093/jb/mvi108

Experimental method

X-RAY DIFFRACTION (1.33 Å)