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PDBsum entry 1e8e
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Oxidoreductase(cytochrome)
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PDB id
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1e8e
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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 methylophilus methylotrophus cytochrome c": insights into the structural basis of haem-Ligand detachment.
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Authors
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L.Brennan,
D.L.Turner,
P.Fareleira,
H.Santos.
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Ref.
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J Mol Biol, 2001,
308,
353-365.
[DOI no: ]
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PubMed id
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Abstract
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Cytochrome c" from Methylophilus methylotrophus is a monohaem protein with
124 amino acid residues. The iron has two histidine ligands in the oxidised
form, one of which detaches and picks up a proton when the protein is reduced.
Thus, both forms are paramagnetic. The structure of the oxidised form in
solution, determined from NMR data is presented. The family of structures has an
average backbone rmsd value of 0.53 A, and a heavy atom rmsd value of 0.95 A,
within a target function range of 32 %. This structure is related to class I
cytochromes with an additional helix at the N terminus. The haem-binding site
occurs in a domain essentially lacking secondary structure motifs and the axial
histidinyl residues were found in an unusual near perpendicular orientation.
Moreover, a disulfide bridge is present, an uncommon structural feature among
c-type cytochromes. The disulfide bridge, linking cysteine residues 96 and 104,
forms a loop that confers rigidity and is essential to the detachment of the
axial histidine (His95) as demonstrated by chemical disruption of the S-S bond.
A route for protonation of the distal histidine involving haem propionate 17 is
proposed and discussed in the light of available models for complex membrane
proton pumps.
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Figure 1.
Figure 1. The number of non-redundant upper distance limits
per residue. White indicates intra-residue restraints, light and
dark grey represent sequential and medium range restraints,
respectively, and black represents long range restraints.
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Figure 6.
Figure 6. Haem group, axial ligands and aromatic residues
in the haem pocket of cytochrome c'' of the best structure. Two
views, related by a 90 ° rotation about the z-axis, are
shown to make the distribution of aromatic groups clear.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2001,
308,
353-365)
copyright 2001.
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Secondary reference #1
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Title
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Characterization of the haem environment in methylophilus methylotrophus ferricytochrome c" by 1h-Nmr.
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Authors
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H.S.Costa,
H.Santos,
D.L.Turner.
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Ref.
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Eur J Biochem, 1993,
215,
817-824.
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PubMed id
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Secondary reference #2
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Title
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Involvement of a labile axial histidine in coupling electron and proton transfer in methylophilus methylotrophus cytochrome c''.
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Authors
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H.S.Costa,
H.Santos,
D.L.Turner,
A.V.Xavier.
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Ref.
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Eur J Biochem, 1992,
208,
427-433.
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PubMed id
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Secondary reference #3
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Title
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Characterization and nmr studies of a novel cytochrome c isolated from methylophilus methylotrophus which shows a redox-Linked change os spin-State
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Authors
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H.Santos,
D.L.Turner.
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Ref.
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biochim biophys acta, 1988,
954,
277.
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