Terminal repeats impact collagen triple-helix stability through hydrogen bonding

Yingying Qi, Daoning Zhou, Julian L. Kessler, Rongmao Qiu, S. Michael Yu, Gang Li, Zhao Qin, Yang Li

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Nearly 30% of human proteins have tandem repeating sequences. Structural understanding of the terminal repeats is well-established for many repeat proteins with the common α-helix and β-sheet foldings. By contrast, the sequence-structure interplay of the terminal repeats of the collagen triple-helix remains to be fully explored. As the most abundant human repeat protein and the most prevalent structural component of the extracellular matrix, collagen features a hallmark triple-helix formed by three supercoiled polypeptide chains of long repeating sequences of the Gly-X-Y triplets. Here, with CD characterization of 28 collagen-mimetic peptides (CMPs) featuring various terminal motifs, as well as DSC measurements, crystal structure analysis, and computational simulations, we show that CMPs only differing in terminal repeat may have distinct end structures and stabilities. We reveal that the cross-chain hydrogen bonding mediated by the terminal repeat is key to maintaining the triple-helix's end structure, and that disruption of it with a single amide to carboxylate substitution can lead to destabilization as drastic as 19 °C. We further demonstrate that the terminal repeat also impacts how strong the CMP strands form hybrid triple-helices with unfolded natural collagen chains in tissue. Our findings provide a spatial profile of hydrogen bonding within the CMP triple-helix, marking a critical guideline for future crystallographic or NMR studies of collagen, and algorithms for predicting triple-helix stability, as well as peptide-based collagen assemblies and materials. This study will also inspire new understanding of the sequence-structure relationship of many other complex structural proteins with repeating sequences.

Original languageEnglish (US)
Pages (from-to)12567-12576
Number of pages10
JournalChemical Science
Volume13
Issue number42
DOIs
StatePublished - Oct 20 2022
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry

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