2guv
From Proteopedia
(New page: 200px<br /><applet load="2guv" size="450" color="white" frame="true" align="right" spinBox="true" caption="2guv, resolution 1.40Å" /> '''Conformational Trans...) |
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| - | [[Image:2guv.gif|left|200px]]<br /><applet load="2guv" size=" | + | [[Image:2guv.gif|left|200px]]<br /><applet load="2guv" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2guv, resolution 1.40Å" /> | caption="2guv, resolution 1.40Å" /> | ||
'''Conformational Transition between Four- and Five-stranded Phenylalanine Zippers Determined by a Local Packing Interaction'''<br /> | '''Conformational Transition between Four- and Five-stranded Phenylalanine Zippers Determined by a Local Packing Interaction'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Alpha-helical coiled coils play a crucial role in mediating specific | + | Alpha-helical coiled coils play a crucial role in mediating specific protein-protein interactions. However, the rules and mechanisms that govern helix-helix association in coiled coils remain incompletely understood. Here we have engineered a seven heptad "Phe-zipper" protein (Phe-14) with phenylalanine residues at all 14 hydrophobic a and d positions, and generated a further variant (Phe-14(M)) in which a single core Phe residue is substituted with Met. Phe-14 forms a discrete alpha-helical pentamer in aqueous solution, while Phe-14(M) folds into a tetrameric helical structure. X-ray crystal structures reveal that in both the tetramer and the pentamer the a and d side-chains interlock in a classical knobs-into-holes packing to produce parallel coiled-coil structures enclosing large tubular cavities. However, the presence of the Met residue in the apolar interface of the tetramer markedly alters its local coiled-coil conformation and superhelical geometry. Thus, short-range interactions involving the Met side-chain serve to preferentially select for tetramer formation, either by inhibiting a nucleation step essential for pentamer folding or by abrogating an intermediate required to form the pentamer. Although specific trigger sequences have not been clearly identified in dimeric coiled coils, higher-order coiled coils, as well as other oligomeric multi-protein complexes, may require such sequences to nucleate and direct their assembly. |
==About this Structure== | ==About this Structure== | ||
| - | 2GUV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http:// | + | 2GUV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GUV OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[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 folding]] | [[Category: protein folding]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:35:41 2008'' |
Revision as of 15:35, 21 February 2008
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Conformational Transition between Four- and Five-stranded Phenylalanine Zippers Determined by a Local Packing Interaction
Overview
Alpha-helical coiled coils play a crucial role in mediating specific protein-protein interactions. However, the rules and mechanisms that govern helix-helix association in coiled coils remain incompletely understood. Here we have engineered a seven heptad "Phe-zipper" protein (Phe-14) with phenylalanine residues at all 14 hydrophobic a and d positions, and generated a further variant (Phe-14(M)) in which a single core Phe residue is substituted with Met. Phe-14 forms a discrete alpha-helical pentamer in aqueous solution, while Phe-14(M) folds into a tetrameric helical structure. X-ray crystal structures reveal that in both the tetramer and the pentamer the a and d side-chains interlock in a classical knobs-into-holes packing to produce parallel coiled-coil structures enclosing large tubular cavities. However, the presence of the Met residue in the apolar interface of the tetramer markedly alters its local coiled-coil conformation and superhelical geometry. Thus, short-range interactions involving the Met side-chain serve to preferentially select for tetramer formation, either by inhibiting a nucleation step essential for pentamer folding or by abrogating an intermediate required to form the pentamer. Although specific trigger sequences have not been clearly identified in dimeric coiled coils, higher-order coiled coils, as well as other oligomeric multi-protein complexes, may require such sequences to nucleate and direct their assembly.
About this Structure
2GUV is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Conformational transition between four and five-stranded phenylalanine zippers determined by a local packing interaction., Liu J, Zheng Q, Deng Y, Kallenbach NR, Lu M, J Mol Biol. 2006 Aug 4;361(1):168-79. Epub 2006 Jun 13. PMID:16828114
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