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PDBsum entry 1snr
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Oxidoreductase
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PDB id
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1snr
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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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Side-On copper-Nitrosyl coordination by nitrite reductase.
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Authors
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E.I.Tocheva,
F.I.Rosell,
A.G.Mauk,
M.E.Murphy.
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Ref.
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Science, 2004,
304,
867-870.
[DOI no: ]
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PubMed id
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Abstract
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A copper-nitrosyl intermediate forms during the catalytic cycle of nitrite
reductase, the enzyme that mediates the committed step in bacterial
denitrification. The crystal structure of a type 2 copper-nitrosyl complex of
nitrite reductase reveals an unprecedented side-on binding mode in which the
nitrogen and oxygen atoms are nearly equidistant from the copper cofactor.
Comparison of this structure with a refined nitrite-bound crystal structure
explains how coordination can change between copper-oxygen and copper-nitrogen
during catalysis. The side-on copper-nitrosyl in nitrite reductase expands the
possibilities for nitric oxide interactions in copper proteins such as
superoxide dismutase and prions.
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Figure 1.
Fig. 1. Stereo views of the type 2 Cu sites with (A) bound
nitrite and (B) nitric oxide. In each panel, the electron
density represented in gray is a 2F[o] - F[c] map contoured at
0.55 e^-/Å3 (1.2  for each
structure). Omit difference maps of the nitrite and nitric oxide
ligands are colored in green and contoured at 0.6 e^-/Å3
(5.1 for NO[2]^- and
4.6 for NO). Carbons
(orange), oxygens (red), nitrogens (blue), type 2 Cu (brown),
and waters (cyan) are colored as indicated. (C) Overview of the
essential features of the active sites of NiR bound with nitrite
(left) and with nitric oxide (right). Metal-ligand bonds
(solid), as well as H bonds and other electrostatic interactions
(dashed), are shown as gray lines of the type indicated.
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Figure 3.
Fig. 3. Revised mechanism of Cu-containing nitrite reductase.
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The above figures are
reprinted
by permission from the AAAs:
Science
(2004,
304,
867-870)
copyright 2004.
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