1qwo
From Proteopedia
(New page: 200px<br /><applet load="1qwo" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qwo, resolution 1.50Å" /> '''Crystal structure of...) |
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| - | [[Image:1qwo.gif|left|200px]]<br /><applet load="1qwo" size=" | + | [[Image:1qwo.gif|left|200px]]<br /><applet load="1qwo" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1qwo, resolution 1.50Å" /> | caption="1qwo, resolution 1.50Å" /> | ||
'''Crystal structure of a phosphorylated phytase from Aspergillus fumigatus, revealing the structural basis for its heat resilience and catalytic pathway'''<br /> | '''Crystal structure of a phosphorylated phytase from Aspergillus fumigatus, revealing the structural basis for its heat resilience and catalytic pathway'''<br /> | ||
==Overview== | ==Overview== | ||
| - | In order to understand the structural basis for the high thermostability | + | In order to understand the structural basis for the high thermostability of phytase from Aspergillus fumigatus, its crystal structure was determined at 1.5 A resolution. The overall fold resembles the structure of other phytase enzymes. Aspergillus niger phytase shares 66% sequence identity, however, it is much less heat-resistant. A superimposition of these two structures reveals some significant differences. In particular, substitutions with polar residues appear to remove repulsive ion pair interactions and instead form hydrogen bond interactions, which stabilize the enzyme; the formation of a C-terminal helical capping, induced by arginine residue substitutions also appears to be critical for the enzyme's ability to refold to its active form after denaturation at high temperature. The heat-resilient property of A.fumigatus phytase could be due to the improved stability of regions that are critical for the refolding of the protein; and a heat-resistant A.niger phytase may be achieved by mutating certain critical residues with the equivalent residues in A.fumigatus phytase. Six predicted N-glycosylation sites were observed to be glycosylated from the experimental electron density. Furthermore, the enzyme's catalytic residue His59 was found to be partly phosphorylated and thus showed a reaction intermediate, providing structural insight, which may help understand the catalytic mechanism of the acid phosphatase family. The trap of this catalytic intermediate confirms the two-step catalytic mechanism of the acid histidine phosphatase family. |
==About this Structure== | ==About this Structure== | ||
| - | 1QWO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Aspergillus_fumigatus Aspergillus fumigatus] with NAG and PO3 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/3-phytase 3-phytase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.8 3.1.3.8] Full crystallographic information is available from [http:// | + | 1QWO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Aspergillus_fumigatus Aspergillus fumigatus] with <scene name='pdbligand=NAG:'>NAG</scene> and <scene name='pdbligand=PO3:'>PO3</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/3-phytase 3-phytase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.8 3.1.3.8] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QWO OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Aspergillus fumigatus]] | [[Category: Aspergillus fumigatus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Deacon, A | + | [[Category: Deacon, A M.]] |
[[Category: Hao, Q.]] | [[Category: Hao, Q.]] | ||
[[Category: Koshy, M.]] | [[Category: Koshy, M.]] | ||
| - | [[Category: Kriksunov, I | + | [[Category: Kriksunov, I A.]] |
| - | [[Category: Lei, X | + | [[Category: Lei, X G.]] |
[[Category: Liu, Q.]] | [[Category: Liu, Q.]] | ||
| - | [[Category: Thiel, D | + | [[Category: Thiel, D J.]] |
[[Category: Xiang, T.]] | [[Category: Xiang, T.]] | ||
[[Category: NAG]] | [[Category: NAG]] | ||
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[[Category: phosphohistidine]] | [[Category: phosphohistidine]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:44:30 2008'' |
Revision as of 12:44, 21 February 2008
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Crystal structure of a phosphorylated phytase from Aspergillus fumigatus, revealing the structural basis for its heat resilience and catalytic pathway
Overview
In order to understand the structural basis for the high thermostability of phytase from Aspergillus fumigatus, its crystal structure was determined at 1.5 A resolution. The overall fold resembles the structure of other phytase enzymes. Aspergillus niger phytase shares 66% sequence identity, however, it is much less heat-resistant. A superimposition of these two structures reveals some significant differences. In particular, substitutions with polar residues appear to remove repulsive ion pair interactions and instead form hydrogen bond interactions, which stabilize the enzyme; the formation of a C-terminal helical capping, induced by arginine residue substitutions also appears to be critical for the enzyme's ability to refold to its active form after denaturation at high temperature. The heat-resilient property of A.fumigatus phytase could be due to the improved stability of regions that are critical for the refolding of the protein; and a heat-resistant A.niger phytase may be achieved by mutating certain critical residues with the equivalent residues in A.fumigatus phytase. Six predicted N-glycosylation sites were observed to be glycosylated from the experimental electron density. Furthermore, the enzyme's catalytic residue His59 was found to be partly phosphorylated and thus showed a reaction intermediate, providing structural insight, which may help understand the catalytic mechanism of the acid phosphatase family. The trap of this catalytic intermediate confirms the two-step catalytic mechanism of the acid histidine phosphatase family.
About this Structure
1QWO is a Single protein structure of sequence from Aspergillus fumigatus with and as ligands. Active as 3-phytase, with EC number 3.1.3.8 Full crystallographic information is available from OCA.
Reference
Crystal structure of a heat-resilient phytase from Aspergillus fumigatus, carrying a phosphorylated histidine., Xiang T, Liu Q, Deacon AM, Koshy M, Kriksunov IA, Lei XG, Hao Q, Thiel DJ, J Mol Biol. 2004 May 28;339(2):437-45. PMID:15136045
Page seeded by OCA on Thu Feb 21 14:44:30 2008
Categories: 3-phytase | Aspergillus fumigatus | Single protein | Deacon, A M. | Hao, Q. | Koshy, M. | Kriksunov, I A. | Lei, X G. | Liu, Q. | Thiel, D J. | Xiang, T. | NAG | PO3 | Alpha barrel | Beta sandwich | Glycoprotein | Orthogonal bundle | Phosphohistidine
