Collagen structure: the Madras triple helix and the current scenario.
Level 5 - mechanism / opinion, no new human data
Narrative review of structural biology and biophysical studies (Level 5 by design analogy).
PubMed 16036578 · doi:10.1080/15216540500090710
What was done
This narrative review summarizes the 50-year evolution of collagen structural models since Ramachandran's Madras coiled-coil triple-helix proposal, evaluating findings from high-resolution crystal structures of collagen-like oligopeptides and stability studies of synthetic collagen mimics.
What was found
The abstract reports no numerical data. It notes that subsequent modeling and crystal structures confirmed the core triple-helical architecture requiring a mandatory glycine at every third residue. It also confirmed that the structure is stabilized by one direct interchain hydrogen bond per tripeptide along with water-mediated hydrogen bonds (modifying the original two-direct-bond model), affirmed the stabilizing role of hydroxyproline residues in fibers, and identified sequence-dependent structural variations.
Why it matters
The review synthesizes structural refinements to the classic collagen model, highlighting how hydration networks and specific amino acid positions govern triple-helix stability and fiber assembly.
Limits
As a narrative review, it lacks systematic search methodology, formal study selection criteria, and quantitative synthesis. The abstract provides no specific structural coordinates, resolution metrics, or thermodynamic values.
Cited by
- context Collagen's primary molecular structure is a repeating tripeptide sequence composed largely of glycine, proline, and 4-hydroxyproline.