1poa
From Proteopedia
(New page: 200px<br /><applet load="1poa" size="450" color="white" frame="true" align="right" spinBox="true" caption="1poa, resolution 1.5Å" /> '''INTERFACIAL CATALYSIS...) |
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| - | [[Image:1poa.gif|left|200px]]<br /><applet load="1poa" size=" | + | [[Image:1poa.gif|left|200px]]<br /><applet load="1poa" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1poa, resolution 1.5Å" /> | caption="1poa, resolution 1.5Å" /> | ||
'''INTERFACIAL CATALYSIS: THE MECHANISM OF PHOSPHOLIPASE A2'''<br /> | '''INTERFACIAL CATALYSIS: THE MECHANISM OF PHOSPHOLIPASE A2'''<br /> | ||
==Overview== | ==Overview== | ||
| - | A chemical description of the action of phospholipase A2 (PLA2) can now be | + | A chemical description of the action of phospholipase A2 (PLA2) can now be inferred with confidence from three high-resolution x-ray crystal structures. The first is the structure of the PLA2 from the venom of the Chinese cobra (Naja naja atra) in a complex with a phosphonate transition-state analogue. This enzyme is typical of a large, well-studied homologous family of PLA2S. The second is a similar complex with the evolutionarily distant bee-venom PLA2. The third structure is the uninhibited PLA2 from Chinese cobra venom. Despite the different molecular architectures of the cobra and bee-venom PLA2s, the transition-state analogue interacts in a nearly identical way with the catalytic machinery of both enzymes. The disposition of the fatty-acid side chains suggests a common access route of the substrate from its position in the lipid aggregate to its productive interaction with the active site. Comparison of the cobra-venom complex with the uninhibited enzyme indicates that optimal binding and catalysis at the lipid-water interface is due to facilitated substrate diffusion from the interfacial binding surface to the catalytic site rather than an allosteric change in the enzyme's structure. However, a second bound calcium ion changes its position upon the binding of the transition-state analogue, suggesting a mechanism for augmenting the critical electrophile. |
==About this Structure== | ==About this Structure== | ||
| - | 1POA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Naja_atra Naja atra] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Phospholipase_A(2) Phospholipase A(2)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.4 3.1.1.4] Full crystallographic information is available from [http:// | + | 1POA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Naja_atra Naja atra] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Phospholipase_A(2) Phospholipase A(2)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.4 3.1.1.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1POA OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Otwinowski, Z.]] | [[Category: Otwinowski, Z.]] | ||
| - | [[Category: Scott, D | + | [[Category: Scott, D L.]] |
| - | [[Category: Sigler, P | + | [[Category: Sigler, P B.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: hydrolase]] | [[Category: hydrolase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:30:45 2008'' |
Revision as of 12:30, 21 February 2008
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INTERFACIAL CATALYSIS: THE MECHANISM OF PHOSPHOLIPASE A2
Overview
A chemical description of the action of phospholipase A2 (PLA2) can now be inferred with confidence from three high-resolution x-ray crystal structures. The first is the structure of the PLA2 from the venom of the Chinese cobra (Naja naja atra) in a complex with a phosphonate transition-state analogue. This enzyme is typical of a large, well-studied homologous family of PLA2S. The second is a similar complex with the evolutionarily distant bee-venom PLA2. The third structure is the uninhibited PLA2 from Chinese cobra venom. Despite the different molecular architectures of the cobra and bee-venom PLA2s, the transition-state analogue interacts in a nearly identical way with the catalytic machinery of both enzymes. The disposition of the fatty-acid side chains suggests a common access route of the substrate from its position in the lipid aggregate to its productive interaction with the active site. Comparison of the cobra-venom complex with the uninhibited enzyme indicates that optimal binding and catalysis at the lipid-water interface is due to facilitated substrate diffusion from the interfacial binding surface to the catalytic site rather than an allosteric change in the enzyme's structure. However, a second bound calcium ion changes its position upon the binding of the transition-state analogue, suggesting a mechanism for augmenting the critical electrophile.
About this Structure
1POA is a Single protein structure of sequence from Naja atra with as ligand. Active as Phospholipase A(2), with EC number 3.1.1.4 Full crystallographic information is available from OCA.
Reference
Interfacial catalysis: the mechanism of phospholipase A2., Scott DL, White SP, Otwinowski Z, Yuan W, Gelb MH, Sigler PB, Science. 1990 Dec 14;250(4987):1541-6. PMID:2274785
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