Atomic resolution crystal structure of squid ganglion DFPase.

Abstract

Diisopropylfluorophosphatases (DFP-ases) are capable of detoxifying chemical warfare agents like diisopropylfluorophosphate (DFP) by hydrolysis. The protein reported here was recombinantely expressed in E. coli. The X-ray crystal structure of this enzyme has been refined to a resolution of 0.85 A and a crystallographic R value of 9.4%. Reversible flash-cooling improved both, mosaicity and resolution of the crystals considerably. The overall structure of this protein represents a six-bladed beta-propeller with two calcium ions bound in a central water filled tunnel. 496 water, 2 glycerol, 2 MES-buffer molecules, and 18 PEG fragments of different lengths could be refined in the solvent region. The 208 most reliable residues, without disorder or reduced occupancy in their side-chains, were finally refined without restraints. A subsequent full-matrix refinement cycle for the positional parameters yielded estimated standard deviations (esds) by matrix inversion. The herewith calculated bond lengths and bond-esds were used to obtain averaged bond lengths, which have been compared to the restraints used in preceding refinement cycles.

• Authors: Juergen Koepke, Eileen I Scharff, Christian Lücke, Heinz Rüterjans, Günter Fritzsch
• Journal: Acta crystallographica. Section D, Biological crystallography (Acta Crystallogr D Biol Crystallogr) Vol. 58 Issue Pt 10 Pt 1 Pg. 1757-9 (Oct 2002) ISSN: 0907-4449 [Print] United States
• PMID: 12351901 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Recombinant Proteins
• Esterases
• Phosphoric Triester Hydrolases
• diisopropyl-fluorophosphatase

Topics

• Animals
• Crystallography, X-Ray
• Decapodiformes (enzymology)
• Esterases (chemistry)
• Ganglia (enzymology)
• Models, Molecular
• Phosphoric Triester Hydrolases
• Protein Conformation
• Recombinant Proteins (chemistry)
• Static Electricity