Mechanical recruitment of N- and C-crosslinks in collagen type I

Albert L. Kwansa, Raffaella De Vita, Joseph W. Freeman

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Collagen type I is an extracellular matrix protein found in connective tissues such as tendon, ligament, bone, skin, and the cornea of the eyes, where it functions to provide tensile strength; it also serves as a scaffold for cells and other extracellular matrix components. A single collagen type I molecule is composed of three amino acid chains that form a triple helix for most of the molecule's length; non-triple-helical extensions called N- and C-telopeptides are located at the amino/N-terminal and carboxy/C-terminal ends of the molecule, respectively. In two of the three chains, the C-telopeptide has been reported to possess a hair-pin/hook conformation, while the three N-telopeptides display a more extended structure. These telopeptides are crucial for the formation of enzymatic covalent crosslinks that form in collagens near their N- and C-ends. Such crosslinks provide structural integrity, strength, and stiffness to collagenous tissues. However, deformation mechanisms of N- and C-crosslinks and functional roles for the N- and C-telopeptide conformations are not yet well known. By performing molecular dynamics simulations, we demonstrated that two dehydro-hydroxylysino-norleucine crosslinks, positioned at the N- and C-crosslinking sites, exhibited a two-stage response to the mechanical deformation of their parent molecules. We observed that the N-crosslink served as the first responder to mechanical deformation, followed by the C-crosslink. The results of our simulations suggest a mechanical recruitment mechanism for N- and C-crosslinks. Understanding this mechanism will be crucial for the development of larger-scale predictive models of the mechanical behavior of native collagenous tissues, engineered tissues, and collagen-based materials.

Original languageEnglish (US)
Pages (from-to)161-169
Number of pages9
JournalMatrix Biology
Volume34
DOIs
StatePublished - Feb 2014

All Science Journal Classification (ASJC) codes

  • Molecular Biology

Keywords

  • Collagen type I
  • Crosslink
  • Molecular dynamics
  • Molecular model
  • Telopeptide

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