Sub-Ångstrom structure of collagen model peptide (GPO)10 shows a hydrated triple helix with pitch variation and two proline ring conformations

• Published in: Food chemistry Vol. 319; p. 126598
• Main Authors: Suzuki, Hironori, Mahapatra, Deepti, Board, Amanda J., Steel, Peter J., Dyer, Jolon M., Gerrard, Juliet A., Dobson, Renwick C.J., Valéry, Céline
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 30.07.2020
• Subjects: Collagen model peptide; Proline ring conformation; Sub-Ångstrom crystal structure; Triple helical symmetry; Triple helix hydration; Sub-Ångstrom crystal structure; Triple helical symmetry; Collagen model peptide; Proline ring conformation; Triple helix hydration
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2020.126598

•An ultra-high 0.89-Å resolution crystal structure of a collagen peptide is reported.•The proline rings exist in either the puckered-up or puckered-down conformations.•Hydroxyproline forms inter-helix interactions and is in the puckered-up conformation.•Evidence suggests pitch variation around an average 7/2 pitch conformation. Collagens are large structural proteins that are prevalent in mammalian connective tissue. Peptides designed to include a glycine-proline-hydroxyproline (GPO) amino acid triad are biomimetic analogs of the collagen triple helix, a fold that is a hallmark of collagen-like sequences. To inform the rational engineering of collagen-like peptides and proteins for food systems, we report the crystal structure of the (GPO)10 peptide at 0.89-Å resolution, solved using direct methods. We determined that a single chain in the asymmetric unit forms a pseudo-hexagonal network of triple helices that have a pitch variation consistent with the model 7/2 helix (3.5 residues per turn). The proline rings occupied one of two states, while the helix was found to have a well-defined hydration shell involved in the stabilization of the inter-helix crystal network. This structure offers a new high-resolution basis for understanding the hierarchical assembly of native collagens, which will aid the food industry in engineering new sustainable food systems.