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| [[Image:2b22.gif|left|200px]] | | {{Seed}} |
| | [[Image:2b22.png|left|200px]] |
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| {{STRUCTURE_2b22| PDB=2b22 | SCENE= }} | | {{STRUCTURE_2b22| PDB=2b22 | SCENE= }} |
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| '''Antiparallel four-stranded coiled coil specified by a 3-3-1 hydrophobic heptad repeat'''
| | ===Antiparallel four-stranded coiled coil specified by a 3-3-1 hydrophobic heptad repeat=== |
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| ==Overview==
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| Coiled-coil sequences in proteins commonly share a seven-amino acid repeat with nonpolar side chains at the first (a) and fourth (d) positions. We investigate here the role of a 3-3-1 hydrophobic repeat containing nonpolar amino acids at the a, d, and g positions in determining the structures of coiled coils using mutants of the GCN4 leucine zipper dimerization domain. When three charged residues at the g positions in the parental sequence are replaced by nonpolar alanine or valine side chains, stable four-helix structures result. The X-ray crystal structures of the tetramers reveal antiparallel, four-stranded coiled coils in which the a, d, and g side chains interlock in a combination of knobs-into-knobs and knobs-into-holes packing. Interfacial interactions in a coiled coil can therefore be prescribed by hydrophobic-polar patterns beyond the canonical 3-4 heptad repeat. The results suggest that the conserved, charged residues at the g positions in the GCN4 leucine zipper can impart a negative design element to disfavor thermodynamically more stable, antiparallel tetramers.
| | The line below this paragraph, {{ABSTRACT_PUBMED_16472744}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 16472744 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_16472744}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Protein design]] | | [[Category: Protein design]] |
| [[Category: Protein structure]] | | [[Category: Protein structure]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 19:45:21 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 09:31:50 2008'' |
