2hy6
From Proteopedia
(New page: 200px<br /><applet load="2hy6" size="350" color="white" frame="true" align="right" spinBox="true" caption="2hy6, resolution 1.25Å" /> '''A seven-helix coiled...) |
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==Overview== | ==Overview== | ||
| - | Coiled-coil proteins contain a characteristic seven-residue sequence | + | Coiled-coil proteins contain a characteristic seven-residue sequence repeat whose positions are designated a to g. The interacting surface between alpha-helices in a classical coiled coil is formed by interspersing nonpolar side chains at the a and d positions with hydrophilic residues at the flanking e and g positions. To explore how the chemical nature of these core amino acids dictates the overall coiled-coil architecture, we replaced all eight e and g residues in the GCN4 leucine zipper with nonpolar alanine side chains. Surprisingly, the alanine-containing mutant forms a stable alpha-helical heptamer in aqueous solution. The 1.25-A resolution crystal structure of the heptamer reveals a parallel seven-stranded coiled coil enclosing a large tubular channel with an unusual heptad register shift between adjacent staggered helices. The overall geometry comprises two interleaved hydrophobic helical screws of interacting cross-sectional a and d layers that have not been seen before. Moreover, asparagines at the a positions play an essential role in heptamer formation by participating in a set of buried interhelix hydrogen bonds. These results demonstrate that heptad repeats containing four hydrophobic positions can direct assembly of complex, higher-order coiled-coil structures with rich diversity for close packing of alpha-helices. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Saccharomyces cerevisiae]] | [[Category: Saccharomyces cerevisiae]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Cheng, C | + | [[Category: Cheng, C S.]] |
[[Category: Deng, Y.]] | [[Category: Deng, Y.]] | ||
| - | [[Category: Kallenbach, N | + | [[Category: Kallenbach, N R.]] |
[[Category: Liu, J.]] | [[Category: Liu, J.]] | ||
[[Category: Lu, M.]] | [[Category: Lu, M.]] | ||
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[[Category: protein structure]] | [[Category: protein structure]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:47:04 2008'' |
Revision as of 15:47, 21 February 2008
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A seven-helix coiled coil
Overview
Coiled-coil proteins contain a characteristic seven-residue sequence repeat whose positions are designated a to g. The interacting surface between alpha-helices in a classical coiled coil is formed by interspersing nonpolar side chains at the a and d positions with hydrophilic residues at the flanking e and g positions. To explore how the chemical nature of these core amino acids dictates the overall coiled-coil architecture, we replaced all eight e and g residues in the GCN4 leucine zipper with nonpolar alanine side chains. Surprisingly, the alanine-containing mutant forms a stable alpha-helical heptamer in aqueous solution. The 1.25-A resolution crystal structure of the heptamer reveals a parallel seven-stranded coiled coil enclosing a large tubular channel with an unusual heptad register shift between adjacent staggered helices. The overall geometry comprises two interleaved hydrophobic helical screws of interacting cross-sectional a and d layers that have not been seen before. Moreover, asparagines at the a positions play an essential role in heptamer formation by participating in a set of buried interhelix hydrogen bonds. These results demonstrate that heptad repeats containing four hydrophobic positions can direct assembly of complex, higher-order coiled-coil structures with rich diversity for close packing of alpha-helices.
About this Structure
2HY6 is a Single protein structure of sequence from Saccharomyces cerevisiae with as ligand. Full crystallographic information is available from OCA.
Reference
A seven-helix coiled coil., Liu J, Zheng Q, Deng Y, Cheng CS, Kallenbach NR, Lu M, Proc Natl Acad Sci U S A. 2006 Oct 17;103(42):15457-62. Epub 2006 Oct 9. PMID:17030805
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