Collagen: Difference between revisions
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== Your Most Plentiful Protein == | == Your Most Plentiful Protein == | ||
[[Image:MotM Collagen.gif|right]] | [[Image:MotM Collagen.gif|right |thumb]] | ||
About one quarter of all of the protein in your body is collagen. Collagen is a major structural protein, forming molecular cables that strengthen the tendons and vast, resilient sheets that support the skin and internal organs. Collagen provides structure to our bodies, protecting and supporting the softer tissues and connecting them with the skeleton. But, in spite of its critical function in the body, collagen is a relatively simple protein. | About one quarter of all of the protein in your body is collagen. Collagen is a major structural protein, forming molecular cables that strengthen the tendons and vast, resilient sheets that support the skin and internal organs. Collagen provides structure to our bodies, protecting and supporting the softer tissues and connecting them with the skeleton. But, in spite of its critical function in the body, collagen is a relatively simple protein. | ||
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<applet load='1cag' size='300' frame='true' align='right' /> | <applet load='1cag' size='300' frame='true' align='right' /> | ||
[[Image:MotM 1bkv.gif|right]] | [[Image:MotM 1bkv.gif |right thumb]] | ||
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. | ||
[[Image:MotM Painting.gif|left | | [[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 | ||
