View source for 1ezg


==CRYSTAL STRUCTURE OF ANTIFREEZE PROTEIN FROM THE BEETLE, TENEBRIO MOLITOR==
<StructureSection load='1ezg' size='340' side='right'caption='[[1ezg]], [[Resolution|resolution]] 1.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ezg]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Tenebrio_molitor Tenebrio molitor]. The December 2009 RCSB PDB [https://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''Antifreeze Proteins''  by David Goodsell is [https://dx.doi.org/10.2210/rcsb_pdb/mom_2009_12 10.2210/rcsb_pdb/mom_2009_12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EZG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1EZG FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.4&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1ezg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ezg OCA], [https://pdbe.org/1ezg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ezg RCSB], [https://www.ebi.ac.uk/pdbsum/1ezg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ezg ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ANPY1_TENMO ANPY1_TENMO] Contributes to protect body fluid from freezing at subzero temperatures. Lowers the freezing point of the hemolymph by about 2.5 degrees at a concentration of 1 mg/ml. Binds to nascent ice crystals and prevents further growth.<ref>PMID:10471292</ref> <ref>PMID:10833402</ref> <ref>PMID:9285581</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ez/1ezg_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1ezg ConSurf].
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== Publication Abstract from PubMed ==
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.

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<ref>PMID:10917536</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1ezg" style="background-color:#fffaf0;"></div>

==See Also==
*[[Antifreeze protein 3D structures|Antifreeze protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Antifreeze Proteins]]
[[Category: Large Structures]]
[[Category: RCSB PDB Molecule of the Month]]
[[Category: Tenebrio molitor]]
[[Category: Davies PL]]
[[Category: Jia Z]]
[[Category: Liou Y-C]]
[[Category: Tocilj A]]