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1m8n
From Proteopedia
(New page: 200px<br /><applet load="1m8n" size="450" color="white" frame="true" align="right" spinBox="true" caption="1m8n, resolution 2.45Å" /> '''Choristoneura Fumife...) |
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| - | [[Image:1m8n.gif|left|200px]]<br /><applet load="1m8n" size=" | + | [[Image:1m8n.gif|left|200px]]<br /><applet load="1m8n" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1m8n, resolution 2.45Å" /> | caption="1m8n, resolution 2.45Å" /> | ||
'''Choristoneura Fumiferana (Spruce Budworm) Antifreeze Protein Isoform 501'''<br /> | '''Choristoneura Fumiferana (Spruce Budworm) Antifreeze Protein Isoform 501'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The insect spruce budworm (Choristoneura fumiferana)(Cf) produces a number | + | The insect spruce budworm (Choristoneura fumiferana)(Cf) produces a number of isoforms of its highly active antifreeze protein (CfAFP). Although most of the CfAFP isoforms are in the 9-kDa range, isoforms containing a 30- or 31-amino acid insertion have also been identified. Here we describe the functional and structural analysis of a selected long isoform, CfAFP-501. X-ray crystal structure determination reveals that the 31-amino acid insertion found in CfAFP-501 forms two additional loops within its highly regular beta-helical structure. This effectively extends the area of the two-dimensional Thr array and ice-binding surface of the protein. The larger isoform has 3 times the thermal hysteresis activity of the 9-kDa CfAFP-337. As well, a deletion of the 31-amino acid insertion within CfAFP-501 to form CfAFP-501-Delta-2-loop, results in a protein with reduced activity similar to the shorter CfAFP isoforms. Thus, the enhanced antifreeze activity of CfAFP-501 is directly correlated to the length of its beta-helical structure and hence the size of its ice-binding face. |
==About this Structure== | ==About this Structure== | ||
| - | 1M8N is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Choristoneura_fumiferana Choristoneura fumiferana]. Full crystallographic information is available from [http:// | + | 1M8N is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Choristoneura_fumiferana Choristoneura fumiferana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1M8N OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Choristoneura fumiferana]] | [[Category: Choristoneura fumiferana]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Davies, P | + | [[Category: Davies, P L.]] |
[[Category: Jia, Z.]] | [[Category: Jia, Z.]] | ||
| - | [[Category: Leinala, E | + | [[Category: Leinala, E K.]] |
[[Category: antifreeze protein]] | [[Category: antifreeze protein]] | ||
[[Category: left-handed beta-helix]] | [[Category: left-handed beta-helix]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:52:45 2008'' |
Revision as of 11:52, 21 February 2008
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Choristoneura Fumiferana (Spruce Budworm) Antifreeze Protein Isoform 501
Overview
The insect spruce budworm (Choristoneura fumiferana)(Cf) produces a number of isoforms of its highly active antifreeze protein (CfAFP). Although most of the CfAFP isoforms are in the 9-kDa range, isoforms containing a 30- or 31-amino acid insertion have also been identified. Here we describe the functional and structural analysis of a selected long isoform, CfAFP-501. X-ray crystal structure determination reveals that the 31-amino acid insertion found in CfAFP-501 forms two additional loops within its highly regular beta-helical structure. This effectively extends the area of the two-dimensional Thr array and ice-binding surface of the protein. The larger isoform has 3 times the thermal hysteresis activity of the 9-kDa CfAFP-337. As well, a deletion of the 31-amino acid insertion within CfAFP-501 to form CfAFP-501-Delta-2-loop, results in a protein with reduced activity similar to the shorter CfAFP isoforms. Thus, the enhanced antifreeze activity of CfAFP-501 is directly correlated to the length of its beta-helical structure and hence the size of its ice-binding face.
About this Structure
1M8N is a Single protein structure of sequence from Choristoneura fumiferana. Full crystallographic information is available from OCA.
Reference
A beta-helical antifreeze protein isoform with increased activity. Structural and functional insights., Leinala EK, Davies PL, Doucet D, Tyshenko MG, Walker VK, Jia Z, J Biol Chem. 2002 Sep 6;277(36):33349-52. Epub 2002 Jun 24. PMID:12105229
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