1cag: Difference between revisions
New page: left|200px<br /> <applet load="1cag" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cag, resolution 1.85Å" /> '''CRYSTAL AND MOLECUL... |
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[[Image:1cag.gif|left|200px]]<br /> | [[Image:1cag.gif|left|200px]]<br /><applet load="1cag" size="350" color="white" frame="true" align="right" spinBox="true" | ||
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caption="1cag, resolution 1.85Å" /> | caption="1cag, resolution 1.85Å" /> | ||
'''CRYSTAL AND MOLECULAR STRUCTURE OF A COLLAGEN-LIKE PEPTIDE AT 1.9 ANGSTROM RESOLUTION'''<br /> | '''CRYSTAL AND MOLECULAR STRUCTURE OF A COLLAGEN-LIKE PEPTIDE AT 1.9 ANGSTROM RESOLUTION'''<br /> | ||
==Overview== | ==Overview== | ||
The structure of a protein triple helix has been determined at 1.9 | The structure of a protein triple helix has been determined at 1.9 angstrom resolution by x-ray crystallographic studies of a collagen-like peptide containing a single substitution of the consensus sequence. This peptide adopts a triple-helical structure that confirms the basic features determined from fiber diffraction studies on collagen: supercoiling of polyproline II helices and interchain hydrogen bonding that follows the model II of Rich and Crick. In addition, the structure provides new information concerning the nature of this protein fold. Each triple helix is surrounded by a cylinder of hydration, with an extensive hydrogen bonding network between water molecules and peptide acceptor groups. Hydroxyproline residues have a critical role in this water network. The interaxial spacing of triple helices in the crystal is similar to that in collagen fibrils, and the water networks linking adjacent triple helices in the crystal structure are likely to be present in connective tissues. The breaking of the repeating (X-Y-Gly)n pattern by a Gly-->Ala substitution results in a subtle alteration of the conformation, with a local untwisting of the triple helix. At the substitution site, direct interchain hydrogen bonds are replaced with interstitial water bridges between the peptide groups. Similar conformational changes may occur in Gly-->X mutated collagens responsible for the diseases osteogenesis imperfecta, chondrodysplasias, and Ehlers-Danlos syndrome IV. | ||
==About this Structure== | ==About this Structure== | ||
1CAG is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ] with ACY as [http://en.wikipedia.org/wiki/ligand ligand]. The following page contains interesting information on the relation of 1CAG with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb4_1.html Collagen]]. Full crystallographic information is available from [http:// | 1CAG is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ] with <scene name='pdbligand=ACY:'>ACY</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. The following page contains interesting information on the relation of 1CAG with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb4_1.html Collagen]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CAG OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Bella, J.]] | [[Category: Bella, J.]] | ||
[[Category: Berman, H | [[Category: Berman, H M.]] | ||
[[Category: Brodsky, B.]] | [[Category: Brodsky, B.]] | ||
[[Category: Eaton, M.]] | [[Category: Eaton, M.]] | ||
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[[Category: collagen]] | [[Category: collagen]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:04:05 2008'' | ||
Revision as of 13:04, 21 February 2008
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CRYSTAL AND MOLECULAR STRUCTURE OF A COLLAGEN-LIKE PEPTIDE AT 1.9 ANGSTROM RESOLUTION
OverviewOverview
The structure of a protein triple helix has been determined at 1.9 angstrom resolution by x-ray crystallographic studies of a collagen-like peptide containing a single substitution of the consensus sequence. This peptide adopts a triple-helical structure that confirms the basic features determined from fiber diffraction studies on collagen: supercoiling of polyproline II helices and interchain hydrogen bonding that follows the model II of Rich and Crick. In addition, the structure provides new information concerning the nature of this protein fold. Each triple helix is surrounded by a cylinder of hydration, with an extensive hydrogen bonding network between water molecules and peptide acceptor groups. Hydroxyproline residues have a critical role in this water network. The interaxial spacing of triple helices in the crystal is similar to that in collagen fibrils, and the water networks linking adjacent triple helices in the crystal structure are likely to be present in connective tissues. The breaking of the repeating (X-Y-Gly)n pattern by a Gly-->Ala substitution results in a subtle alteration of the conformation, with a local untwisting of the triple helix. At the substitution site, direct interchain hydrogen bonds are replaced with interstitial water bridges between the peptide groups. Similar conformational changes may occur in Gly-->X mutated collagens responsible for the diseases osteogenesis imperfecta, chondrodysplasias, and Ehlers-Danlos syndrome IV.
About this StructureAbout this Structure
1CAG is a Protein complex structure of sequences from [1] with as ligand. The following page contains interesting information on the relation of 1CAG with [Collagen]. Full crystallographic information is available from OCA.
ReferenceReference
Crystal and molecular structure of a collagen-like peptide at 1.9 A resolution., Bella J, Eaton M, Brodsky B, Berman HM, Science. 1994 Oct 7;266(5182):75-81. PMID:7695699
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