1ezg
From Proteopedia
(New page: 200px<br /><applet load="1ezg" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ezg, resolution 1.4Å" /> '''CRYSTAL STRUCTURE OF ...) |
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| - | [[Image:1ezg.gif|left|200px]]<br /><applet load="1ezg" size=" | + | [[Image:1ezg.gif|left|200px]]<br /><applet load="1ezg" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ezg, resolution 1.4Å" /> | caption="1ezg, resolution 1.4Å" /> | ||
'''CRYSTAL STRUCTURE OF ANTIFREEZE PROTEIN FROM THE BEETLE, TENEBRIO MOLITOR'''<br /> | '''CRYSTAL STRUCTURE OF ANTIFREEZE PROTEIN FROM THE BEETLE, TENEBRIO MOLITOR'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Insect antifreeze proteins (AFP) are much more effective than fish AFPs at | + | Insect antifreeze proteins (AFP) are much more effective than fish AFPs at depressing solution freezing points by ice-growth inhibition. AFP from the beetle Tenebrio molitor is a small protein (8.4 kDa) composed of tandem 12-residue repeats (TCTxSxxCxxAx). Here we report its 1.4-A resolution crystal structure, showing that this repetitive sequence translates into an exceptionally regular beta-helix. Not only are the 12-amino-acid loops almost identical in the backbone, but also the conserved side chains are positioned in essentially identical orientations, making this AFP perhaps the most regular protein structure yet observed. The protein has almost no hydrophobic core but is stabilized by numerous disulphide and hydrogen bonds. On the conserved side of the protein, threonine-cysteine-threonine motifs are arrayed to form a flat beta-sheet, the putative ice-binding surface. The threonine side chains have exactly the same rotameric conformation and the spacing between OH groups is a near-perfect match to the ice lattice. Together with tightly bound co-planar external water, three ranks of oxygen atoms form a two-dimensional array, mimicking an ice section. |
==About this Structure== | ==About this Structure== | ||
| - | 1EZG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Tenebrio_molitor Tenebrio molitor]. Full crystallographic information is available from [http:// | + | 1EZG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Tenebrio_molitor Tenebrio molitor]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EZG OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Tenebrio molitor]] | [[Category: Tenebrio molitor]] | ||
| - | [[Category: Davies, P | + | [[Category: Davies, P L.]] |
[[Category: Jia, Z.]] | [[Category: Jia, Z.]] | ||
| - | [[Category: Liou, Y | + | [[Category: Liou, Y C.]] |
[[Category: Tocilj, A.]] | [[Category: Tocilj, A.]] | ||
[[Category: insect antifreeze protein]] | [[Category: insect antifreeze protein]] | ||
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[[Category: tmafp]] | [[Category: tmafp]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:33:10 2008'' |
Revision as of 10:33, 21 February 2008
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CRYSTAL STRUCTURE OF ANTIFREEZE PROTEIN FROM THE BEETLE, TENEBRIO MOLITOR
Overview
Insect antifreeze proteins (AFP) are much more effective than fish AFPs at depressing solution freezing points by ice-growth inhibition. AFP from the beetle Tenebrio molitor is a small protein (8.4 kDa) composed of tandem 12-residue repeats (TCTxSxxCxxAx). Here we report its 1.4-A resolution crystal structure, showing that this repetitive sequence translates into an exceptionally regular beta-helix. Not only are the 12-amino-acid loops almost identical in the backbone, but also the conserved side chains are positioned in essentially identical orientations, making this AFP perhaps the most regular protein structure yet observed. The protein has almost no hydrophobic core but is stabilized by numerous disulphide and hydrogen bonds. On the conserved side of the protein, threonine-cysteine-threonine motifs are arrayed to form a flat beta-sheet, the putative ice-binding surface. The threonine side chains have exactly the same rotameric conformation and the spacing between OH groups is a near-perfect match to the ice lattice. Together with tightly bound co-planar external water, three ranks of oxygen atoms form a two-dimensional array, mimicking an ice section.
About this Structure
1EZG is a Single protein structure of sequence from Tenebrio molitor. Full crystallographic information is available from OCA.
Reference
Mimicry of ice structure by surface hydroxyls and water of a beta-helix antifreeze protein., Liou YC, Tocilj A, Davies PL, Jia Z, Nature. 2000 Jul 20;406(6793):322-4. PMID:10917536
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