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PDBsum entry 1ejg
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Plant protein
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PDB id
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1ejg
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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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Accurate protein crystallography at ultra-High resolution: valence electron distribution in crambin.
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Authors
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C.Jelsch,
M.M.Teeter,
V.Lamzin,
V.Pichon-Pesme,
R.H.Blessing,
C.Lecomte.
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Ref.
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Proc Natl Acad Sci U S A, 2000,
97,
3171-3176.
[DOI no: ]
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PubMed id
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Abstract
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The charge density distribution of a protein has been refined experimentally.
Diffraction data for a crambin crystal were measured to ultra-high resolution
(0.54 A) at low temperature by using short-wavelength synchrotron radiation. The
crystal structure was refined with a model for charged, nonspherical, multipolar
atoms to accurately describe the molecular electron density distribution. The
refined parameters agree within 25% with our transferable electron density
library derived from accurate single crystal diffraction analyses of several
amino acids and small peptides. The resulting electron density maps of
redistributed valence electrons (deformation maps) compare quantitatively well
with a high-level quantum mechanical calculation performed on a monopeptide.
This study provides validation for experimentally derived parameters and a
window into charge density analysis of biological macromolecules.
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Figure 1.
Fig. 1. Ribbon diagram (16) showing the general fold of
crambin. The disulfide bridges are shown in yellow.  -sheet and
extended chain are shown in green and the helices are red.
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Figure 2.
Fig. 2. Residual electron density in the peptide bond
plane. (A) For the peptide Ala-9-Arg-10 when using a spherical
neutral atom model, contour level 0.05 e^  /Å3.
(B) Averaged over the 34 nondisordered peptides in crambin when
using a spherical neutral atom model. (C) When using a
multipolar charged atom model transferred from the database and
(D) with average valence populations and multipoles refined,
contour level 0.02 e^ /Å3.
Positive: red lines; negative: blue lines.
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