Introduction - This script shows the structure of collagen. Scroll
down until the text corresponding to the view is visible (Based on
1CAG.pdb, W. Kabach et al. Nature 347 37
(1990)).
A classic collagen triple helix is shown here. The three helices are
red,
yellow and
green.
A special amino acid sequence makes the tight collagen triple helix
particularly stable. Every third amino acid is a
glycine, and many of the remaining amino acids are
proline or
hydroxyproline.
Notice how the glycine forms a tiny elbow
packed inside the helix, while the proline
and hydroxyproline smoothly bend the
chain back around the helix.