2cuo
From Proteopedia
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Collagen model peptide (PRO-PRO-GLY)9
Overview
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.
About this Structure
2CUO is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Repetitive interactions observed in the crystal structure of a collagen-model peptide, [(Pro-Pro-Gly)9]3., Hongo C, Noguchi K, Okuyama K, Tanaka Y, Nishino N, J Biochem (Tokyo). 2005 Aug;138(2):135-44. PMID:16091587
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