2msj: Difference between revisions
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New page: left|200px<br /><applet load="2msj" size="450" color="white" frame="true" align="right" spinBox="true" caption="2msj, resolution 1.90Å" /> '''TYPE III ANTIFREEZE ... |
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[[Image:2msj.jpg|left|200px]]<br /><applet load="2msj" size=" | [[Image:2msj.jpg|left|200px]]<br /><applet load="2msj" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="2msj, resolution 1.90Å" /> | caption="2msj, resolution 1.90Å" /> | ||
'''TYPE III ANTIFREEZE PROTEIN ISOFORM HPLC 12 N46S'''<br /> | '''TYPE III ANTIFREEZE PROTEIN ISOFORM HPLC 12 N46S'''<br /> | ||
==Overview== | ==Overview== | ||
Some cold water marine fishes avoid cellular damage because of freezing by | 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. | ||
==About this Structure== | ==About this Structure== | ||
2MSJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Macrozoarces_americanus Macrozoarces americanus]. Full crystallographic information is available from [http:// | 2MSJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Macrozoarces_americanus Macrozoarces americanus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2MSJ OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Baardsnes, J.]] | [[Category: Baardsnes, J.]] | ||
[[Category: Davies, P | [[Category: Davies, P L.]] | ||
[[Category: Deluca, C | [[Category: Deluca, C I.]] | ||
[[Category: Graether, S | [[Category: Graether, S P.]] | ||
[[Category: Hill, G | [[Category: Hill, G A.]] | ||
[[Category: Jia, Z.]] | [[Category: Jia, Z.]] | ||
[[Category: antifreeze protein]] | [[Category: antifreeze protein]] | ||
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[[Category: thermal hysteresis protein]] | [[Category: thermal hysteresis protein]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:07:53 2008'' | ||