Published:
International Union of Crystallography (IUCr), 2002
Published in:
Acta Crystallographica Section D Biological Crystallography, 58 (2002) 10, Seite 1757-1759
Language:
Not determined
DOI:
10.1107/s0907444902012714
ISSN:
0907-4449
Origination:
Footnote:
Description:
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 cystal structure of this enzyme has been refined to a resolution of 0.85 Å 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 β-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 lenghts and bond-esds were used to obtain averaged bond lengths, which have been compared to the restraints used in preceding refinement cycles.