2iar
From Proteopedia
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[[Image:2iar.jpg|left|200px]] | [[Image:2iar.jpg|left|200px]] | ||
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'''Crystal structure of squid ganglion DFPase W244H mutant''' | '''Crystal structure of squid ganglion DFPase W244H mutant''' | ||
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[[Category: Rueterjans, H.]] | [[Category: Rueterjans, H.]] | ||
[[Category: Scharff, E I.]] | [[Category: Scharff, E I.]] | ||
| - | [[Category: | + | [[Category: Beta-propeller]] |
| - | [[Category: | + | [[Category: Calcium-binding site]] |
| - | [[Category: | + | [[Category: Phosphotriesterase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 07:16:21 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 04:16, 4 May 2008
Crystal structure of squid ganglion DFPase W244H mutant
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
2IAR is a Single protein structure of sequence from Loligo vulgaris. 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 Sun May 4 07:16:21 2008
