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PDBsum entry 3d89
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Electron transport
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PDB id
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3d89
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References listed in PDB file
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Key reference
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Title
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X-Ray structure of a soluble rieske-Type ferredoxin from mus musculus.
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Authors
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E.J.Levin,
N.L.Elsen,
K.D.Seder,
J.G.Mccoy,
B.G.Fox,
G.N.Phillips.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 2008,
64,
933-940.
[DOI no: ]
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PubMed id
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Abstract
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The 2.07 A resolution X-ray crystal structure of a soluble Rieske-type
ferredoxin from Mus musculus encoded by the gene Mm.266515 is reported. Although
they are present as covalent domains in eukaryotic membrane oxidase complexes,
soluble Rieske-type ferredoxins have not previously been observed in eukaryotes.
The overall structure of the mouse Rieske-type ferredoxin is typical of this
class of iron-sulfur proteins and consists of a larger partial beta-barrel
domain and a smaller domain containing Cys57, His59, Cys80 and His83 that binds
the [2Fe-2S] cluster. The S atoms of the cluster are hydrogen-bonded by six
backbone amide N atoms in a pattern typical of membrane-bound high-potential
eukaryotic respiratory Rieske ferredoxins. However, phylogenetic analysis
suggested that the mouse Rieske-type ferredoxin was more closely related to
bacterial Rieske-type ferredoxins. Correspondingly, the structure revealed an
extended loop most similar to that seen in Rieske-type ferredoxin subunits of
bacterial aromatic dioxygenases, including the positioning of an aromatic side
chain (Tyr85) between this loop and the [2Fe-2S] cluster. The mouse Rieske-type
ferredoxin was shown to be capable of accepting electrons from both eukaryotic
and prokaryotic oxidoreductases, although it was unable to serve as an electron
donor for a bacterial monooxygenase complex. The human homolog of mouse
Rieske-type ferredoxin was also cloned and purified. It behaved identically to
mouse Rieske-type ferredoxin in all biochemical characterizations but did not
crystallize. Based on its high sequence identity, the structure of the human
homolog is likely to be modeled well by the mouse Rieske-type ferredoxin
structure.
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Figure 3.
Figure 3 Ribbon representation of mouse soluble Rieske
ferredoxin. The large domain is shown in blue and the
cluster-binding domain in green. The iron-sulfur cluster is
shown as spheres, with the S atoms colored yellow and the Fe
atoms gray. The dashed line indicates the approximate location
of five disordered residues in the  8-
X
loop.
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Figure 5.
Figure 5 Comparison of Rieske ferredoxin folds and the MRF
active site. (a) Stereo image of the alignment of MRF (cyan),
BphF (PDB code 1fqt , gray), T4moC (PDB code 1vm9 , green) and
CarAc (PDB code 1vck , red). The positioning of the
space-filling representation of the iron-sulfur cluster
corresponds to its location in the MRF structure. (b) Stereo
image of the MRF active site and residues participating in
hydrogen bonding to the atoms of the iron-sulfur cluster and the
cysteine S atoms, which are represented as spheres.
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The above figures are
reprinted
from an Open Access publication published by the IUCr:
Acta Crystallogr D Biol Crystallogr
(2008,
64,
933-940)
copyright 2008.
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