View source for 9msi


==TYPE III ANTIFREEZE PROTEIN ISOFORM HPLC 12 T18N==
<StructureSection load='9msi' size='340' side='right'caption='[[9msi]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9msi]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Zoarces_americanus Zoarces americanus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9MSI OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9MSI 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]] 2.6&#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=9msi FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9msi OCA], [https://pdbe.org/9msi PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9msi RCSB], [https://www.ebi.ac.uk/pdbsum/9msi PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9msi ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ANP12_ZOAAM ANP12_ZOAAM] Contributes to protect fish blood from freezing at subzero sea water temperatures. Lowers the blood freezing point. Binds to nascent ice crystals and prevents further growth.
== 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/ms/9msi_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=9msi ConSurf].
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== Publication Abstract from PubMed ==
Some cold water marine fishes avoid cellular damage because of freezing by expressing antifreeze proteins (AFPs) that bind to ice and inhibit its growth; one such protein is the globular type III AFP from eel pout. Despite several studies, the mechanism of ice binding remains unclear because of the difficulty in modeling the AFP-ice interaction. To further explore the mechanism, we have determined the x-ray crystallographic structure of 10 type III AFP mutants and combined that information with 7 previously determined structures to mainly analyze specific AFP-ice interactions such as hydrogen bonds. Quantitative assessment of binding was performed using a neural network with properties of the structure as input and predicted antifreeze activity as output. Using the cross-validation method, a correlation coefficient of 0.60 was obtained between measured and predicted activity, indicating successful learning and good predictive power. A large loss in the predictive power of the neural network occurred after properties related to the hydrophobic surface were left out, suggesting that van der Waal's interactions make a significant contribution to ice binding. By combining the analysis of the neural network with antifreeze activity and x-ray crystallographic structures of the mutants, we extend the existing ice-binding model to a two-step process: 1) probing of the surface for the correct ice-binding plane by hydrogen-bonding side chains and 2) attractive van der Waal's interactions between the other residues of the ice-binding surface and the ice, which increases the strength of the protein-ice interaction.

Quantitative and qualitative analysis of type III antifreeze protein structure and function.,Graether SP, DeLuca CI, Baardsnes J, Hill GA, Davies PL, Jia Z J Biol Chem. 1999 Apr 23;274(17):11842-7. PMID:10207002<ref>PMID:10207002</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Antifreeze protein 3D structures|Antifreeze protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Zoarces americanus]]
[[Category: Baardsnes J]]
[[Category: Davies PL]]
[[Category: Deluca CI]]
[[Category: Graether SP]]
[[Category: Hill GA]]
[[Category: Jia Z]]