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PDBsum entry 1lkb
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Metal binding to porcine pancreatic elastase: calcium or not calcium.
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Authors
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M.S.Weiss,
S.Panjikar,
E.Nowak,
P.A.Tucker.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 2002,
58,
1407-1412.
[DOI no: ]
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PubMed id
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Abstract
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Porcine pancreatic elastase has been crystallized at slightly acidic pH under
two similar but slightly different conditions. Diffraction data were collected
at a wavelength of 1.5 A to a maximum resolution of 1.7 A. Both difference
electron-density maps and anomalous difference electron-density maps suggest
that in crystals grown from a sodium sulfate solution PPE binds Na(+) in its
metal-binding site. In contrast, PPE binds Ca(2+) in crystals grown from a
solution containing sodium citrate and calcium chloride. This observation is in
contradiction to most PPE structures reported in the PDB. In addition to the
metal-binding site, up to three other binding sites, which appear to be
anion-binding sites, could be identified based on the observed anomalous
intensity differences.
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Figure 2.
Figure 2 The metal-binding site of PPE. The metal site is shown
in red, the traces of loop 58-70 in grey and the atoms of the
amino acids and water molecules coordinating the metal in dark
blue (Na[2]SO[4] complex) and light blue (sodium citrate/CaCl[2]
complex). The two structures were superimposed so that the metal
coordinates are identical in both cases. This figure was also
prepared using the programs MOLSCRIPT (Kraulis, 1991[Kraulis, P.
J. (1991). J. Appl. Cryst. 24, 946-950.]) and Raster3D (Merritt
& Bacon, 1997[Merritt, A. E. & Bacon, D. J. (1997). Methods
Enzymol. 277, 505-524.]).
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The above figure is
reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr
(2002,
58,
1407-1412)
copyright 2002.
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