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PDBsum entry 1ocd
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Electron transport
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PDB id
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1ocd
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References listed in PDB file
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Key reference
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Title
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Solution structure of horse heart ferricytochrome c and detection of redox-Related structural changes by high-Resolution 1h nmr.
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Authors
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P.X.Qi,
R.A.Beckman,
A.J.Wand.
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Ref.
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Biochemistry, 1996,
35,
12275-12286.
[DOI no: ]
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PubMed id
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Abstract
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A model for the solution structure of horse heart ferricytochrome c has been
determined by nuclear magnetic resonance spectroscopy combined with hybrid
distance geometry-simulated annealing calculations. Forty-four highly refined
structures were obtained using a total of 1671 distance constraints based on the
observed magnitude of nuclear Overhauser effects and 58 torsion angle restrains
based on the magnitude of determined J-coupling constants. The model
incorporates six long-lived water molecules detected by pseudo-two-dimensional
NOESY-TOCSY spectra. The all-residue root mean square deviation about the
average structure is 0.33 +/- 0.04 A for the backbone N, C alpha, and C' atoms
and 0.83 +/- 0.05 A for all heavy atoms. The overall topology of the model for
solution structure is very similar to that seen in previously reported models
for crystal structures of homologous c-type cytochromes though there are a
number of significant differences in detailed aspects of the structure. Two of
the three main helices display localized irregularities in helical hydrogen
bonding resulting in bifurcation of main chain hydrogen bond acceptor carbonyls.
The N- and C-terminal helices are tightly packed and display several
interhelical interactions not seen in reported crystal models. To provide an
independent measure of the accuracy of the model for the oxidized protein, the
expected pseudocontact shifts induced by the spin 1/2 iron were compared to the
observed redox-dependent chemical shift changes. These comparisons confirm the
general accuracy of the model for the oxidized protein and its observed
differences with the structure of the reduced protein. The structures of the
reduced and oxidized states of the protein provide a template to explain a range
of physical and biological data spanning the redox properties, folding,
molecular recognition, and stability of the cytochrome c molecule. For example,
a redox-dependent reorganization of surface residues at the heme edge can be
directly related to the redox behavior of the protein and thereby provides a
previously undocumented linkage between structural change potentially associated
with molecular recognition of redox partners and the fundamental parameters
governing electron transfer.
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Secondary reference #1
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Title
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Structural water in oxidized and reduced horse heart cytochrome c.
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Authors
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P.X.Qi,
J.L.Urbauer,
E.J.Fuentes,
M.F.Leopold,
A.J.Wand.
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Ref.
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Nat Struct Biol, 1994,
1,
378-382.
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PubMed id
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Secondary reference #2
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Title
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Solution structure of horse heart ferrocytochrome c determined by high-Resolution nmr and restrained simulated annealing.
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Authors
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P.X.Qi,
D.L.Di stefano,
A.J.Wand.
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Ref.
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Biochemistry, 1994,
33,
6408-6417.
[DOI no: ]
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PubMed id
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Secondary reference #3
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Title
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Proton resonance assignments of horse ferricytochrome c.
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Authors
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Y.Feng,
H.Roder,
S.W.Englander,
A.J.Wand,
D.L.Di stefano.
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Ref.
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Biochemistry, 1989,
28,
195-203.
[DOI no: ]
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PubMed id
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