Collagen: Difference between revisions
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<applet load='1cag' size='300' frame='true' align='right' /> | <applet load='1cag' size='300' frame='true' align='right' /> | ||
A special amino acid sequence makes the tight collagen <scene name='Collagen/1cag/5'>triple helix</scene> particularly stable. Every third amino acid is <scene name='Collagen/1cag/1'>a glycine</scene>, and many of the remaining amino acids are <scene name='Collagen/1cag/3'>proline</scene> or <scene name='Collagen/1cag/4'>hydroxyproline</scene>. A classic triple helix is shown here, and may be viewed in the [[1cag]]. Notice how the glycine forms a tiny elbow packed inside the helix, and notice how the proline and hydroxyproline smoothly bend the chain back around the helix. In this structure, the researchers placed a larger <scene name='Collagen/1cag/2'>alanine</scene> amino acid in the position normally occupied by glycine, showing that it crowds the neighboring chains. | A special amino acid sequence makes the tight collagen <scene name='Collagen/1cag/5'>triple helix</scene> particularly stable. Every third amino acid is <scene name='Collagen/1cag/1'>a glycine</scene>, and many of the remaining amino acids are <scene name='Collagen/1cag/3'>proline</scene> or <scene name='Collagen/1cag/4'>hydroxyproline</scene>. A classic triple helix is shown here, and may be viewed in the [[1cag]]. Notice how the glycine forms a tiny elbow packed inside the helix, and notice how the proline and hydroxyproline smoothly bend the chain back around the helix. In this structure, the researchers placed a larger <scene name='Collagen/1cag/2'>alanine</scene> amino acid in the position normally occupied by glycine, showing that it crowds the neighboring chains. | ||
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This illustration depicts a basement membrane, which forms a tough surface that supports the skin and many organs. A different collagen--"type IV"--forms the structural basis of this membrane. Type IV collagen has a globular head at one end and an extra tail at the other. The heads bind strongly together, head-to-head, and four collagen molecules associate together through their tails, forming an X-shaped complex. Using these two types of interactions, type IV collagen forms an extended network, shown above in light blue. Two other molecules--cross-shaped laminin (blue- green) and long, snaky proteoglycans (green)--fill in the spaces, forming a dense sheet. | This illustration depicts a basement membrane, which forms a tough surface that supports the skin and many organs. A different collagen--"type IV"--forms the structural basis of this membrane. Type IV collagen has a globular head at one end and an extra tail at the other. The heads bind strongly together, head-to-head, and four collagen molecules associate together through their tails, forming an X-shaped complex. Using these two types of interactions, type IV collagen forms an extended network, shown above in light blue. Two other molecules--cross-shaped laminin (blue- green) and long, snaky proteoglycans (green)--fill in the spaces, forming a dense sheet. | ||
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[[Image:MotM Painting.gif|left |thumb]] | [[Image:MotM Painting.gif|left |thumb]] | ||
==Another Jmol tutorial== | ==Another Jmol tutorial== | ||
[http://www.messiah.edu/molscilab/Jmol/collagen/collagen_index.htm Tutorial] which illustrates and describes the 3D structure of collagen | [http://www.messiah.edu/molscilab/Jmol/collagen/collagen_index.htm Tutorial] which illustrates and describes the 3D structure of collagen | ||
* Content adapted with permission from David S. Goodsell's [http://mgl.scripps.edu/people/goodsell/pdb/pdb4/pdb4_1.html Molecule of the Month on Collagen] | |||
