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PDBsum entry 2nx0
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Oxygen storage/transport
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PDB id
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2nx0
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References listed in PDB file
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Key reference
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Title
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S-Nitrosylation-Induced conformational change in blackfin tuna myoglobin.
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Authors
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E.R.Schreiter,
M.M.Rodríguez,
A.Weichsel,
W.R.Montfort,
J.Bonaventura.
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Ref.
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J Biol Chem, 2007,
282,
19773-19780.
[DOI no: ]
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PubMed id
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Abstract
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S-nitrosylation is a post-translational protein modification that can alter the
function of a variety of proteins. Despite the growing wealth of information
that this modification may have important functional consequences, little is
known about the structure of the moiety or its effect on protein tertiary
structure. Here we report high-resolution x-ray crystal structures of
S-nitrosylated and unmodified blackfin tuna myoglobin, which demonstrate that in
vitro S-nitrosylation of this protein at the surface-exposed Cys-10 directly
causes a reversible conformational change by "wedging" apart a helix
and loop. Furthermore, we have demonstrated in solution and in a single crystal
that reduction of the S-nitrosylated myoglobin with dithionite results in NO
cleavage from the sulfur of Cys-10 and rebinding to the reduced heme iron,
showing the reversibility of both the modification and the conformational
changes. Finally, we report the 0.95-A structure of ferrous nitrosyl myoglobin,
which provides an accurate structural view of the NO coordination geometry in
the context of a globin heme pocket.
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Figure 1.
FIGURE 1. Electron density for S-nitrosylated Cys-10 of
blackfin tuna myoglobin. Stereo view of the 2F[o] - F[c]
electron density omit map for Cys-10 in S-nitrosylated
myoglobin. The map is contoured at 1.0  and shown in blue mesh.
The final refined model is shown as sticks colored by atom type.
The three modeled conformations of Cys-10 are shown:
conformations A and B are S-nitrosylated, whereas conformation C
is not. All figures were produced using PyMOL.
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Figure 4.
FIGURE 4. 0.95-Å ferrous nitrosyl myoglobin
structure. A, stereo view of the nitrosyl heme and nearby side
chains. The 2F[o] - F[c] electron density map for the heme group
and amino acid side chains, contoured at 3.5 , is shown in brown
mesh. The 2F[o] - F[c] electron density omit map for the NO
group, contoured at 3.5 , is shown in blue
mesh. The final refined model is represented as ball-and-stick
colored by atom type. B, the same as A after rotation by 90°
to give a "top" view.
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The above figures are
reprinted
by permission from the ASBMB:
J Biol Chem
(2007,
282,
19773-19780)
copyright 2007.
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