1e1a
From Proteopedia
| Line 4: | Line 4: | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: Phosphotriesterases (PTE) are enzymes capable of detoxifying | + | BACKGROUND: Phosphotriesterases (PTE) are enzymes capable of detoxifying organophosphate-based chemical warfare agents by hydrolysis. One subclass of these enzymes comprises the family of diisopropylfluorophosphatases (DFPases). The DFPase reported here was originally isolated from squid head ganglion of Loligo vulgaris and can be characterized as squid-type DFPase. It is capable of hydrolyzing the organophosphates diisopropylfluorophosphate, soman, sarin, tabun, and cyclosarin. RESULTS: Crystals were grown of both the native and the selenomethionine-labeled enzyme. The X-ray crystal structure of the DFPase from Loligo vulgaris has been solved by MAD phasing and refined to a crystallographic R value of 17.6% at a final resolution of 1.8 A. Using site-directed mutagenesis, we have structurally and functionally characterized essential residues in the active site of the enzyme. CONCLUSIONS: The crystal structure of the DFPase from Loligo vulgaris is the first example of a structural characterization of a squid-type DFPase and the second crystal structure of a PTE determined to date. Therefore, it may serve as a structural model for squid-type DFPases in general. The overall structure of this protein represents a six-fold beta propeller with two calcium ions bound in a central water-filled tunnel. The consensus motif found in the blades of this beta propeller has not yet been observed in other beta propeller structures. Based on the results obtained from mutants of active-site residues, a mechanistic model for the DFP hydrolysis has been developed. |
==About this Structure== | ==About this Structure== | ||
| Line 18: | Line 18: | ||
[[Category: Luecke, C.]] | [[Category: Luecke, C.]] | ||
[[Category: Rueterjans, H.]] | [[Category: Rueterjans, H.]] | ||
| - | [[Category: Scharff, E | + | [[Category: Scharff, E I.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: beta-propeller]] | [[Category: beta-propeller]] | ||
| Line 25: | Line 25: | ||
[[Category: selenometionine]] | [[Category: selenometionine]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:22:43 2008'' |
Revision as of 10:22, 21 February 2008
|
CRYSTAL STRUCTURE OF DFPASE FROM LOLIGO VULGARIS
Overview
BACKGROUND: Phosphotriesterases (PTE) are enzymes capable of detoxifying organophosphate-based chemical warfare agents by hydrolysis. One subclass of these enzymes comprises the family of diisopropylfluorophosphatases (DFPases). The DFPase reported here was originally isolated from squid head ganglion of Loligo vulgaris and can be characterized as squid-type DFPase. It is capable of hydrolyzing the organophosphates diisopropylfluorophosphate, soman, sarin, tabun, and cyclosarin. RESULTS: Crystals were grown of both the native and the selenomethionine-labeled enzyme. The X-ray crystal structure of the DFPase from Loligo vulgaris has been solved by MAD phasing and refined to a crystallographic R value of 17.6% at a final resolution of 1.8 A. Using site-directed mutagenesis, we have structurally and functionally characterized essential residues in the active site of the enzyme. CONCLUSIONS: The crystal structure of the DFPase from Loligo vulgaris is the first example of a structural characterization of a squid-type DFPase and the second crystal structure of a PTE determined to date. Therefore, it may serve as a structural model for squid-type DFPases in general. The overall structure of this protein represents a six-fold beta propeller with two calcium ions bound in a central water-filled tunnel. The consensus motif found in the blades of this beta propeller has not yet been observed in other beta propeller structures. Based on the results obtained from mutants of active-site residues, a mechanistic model for the DFP hydrolysis has been developed.
About this Structure
1E1A is a Single protein structure of sequence from Loligo vulgaris with as ligand. Active as Diisopropyl-fluorophosphatase, with EC number 3.1.8.2 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Crystal structure of diisopropylfluorophosphatase from Loligo vulgaris., Scharff EI, Koepke J, Fritzsch G, Lucke C, Ruterjans H, Structure. 2001 Jun;9(6):493-502. PMID:11435114
Page seeded by OCA on Thu Feb 21 12:22:43 2008
