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PDBsum entry 1qhq
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Electron transfer
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PDB id
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1qhq
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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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Crystal structure of auracyanin, A "blue" copper protein from the green thermophilic photosynthetic bacterium chloroflexus aurantiacus.
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Authors
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C.S.Bond,
R.E.Blankenship,
H.C.Freeman,
J.M.Guss,
M.J.Maher,
F.M.Selvaraj,
M.C.Wilce,
K.M.Willingham.
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Ref.
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J Mol Biol, 2001,
306,
47-67.
[DOI no: ]
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PubMed id
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Abstract
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Auracyanin B, one of two similar blue copper proteins produced by the
thermophilic green non-sulfur photosynthetic bacterium Chloroflexus aurantiacus,
crystallizes in space group P6(4)22 (a=b=115.7 A, c=54.6 A). The structure was
solved using multiple wavelength anomalous dispersion data recorded about the
CuK absorption edge, and was refined at 1.55 A resolution. The molecular model
comprises 139 amino acid residues, one Cu, 247 H(2)O molecules, one Cl(-) and
two SO(4)(2-). The final residual and estimated standard uncertainties are
R=0.198, ESU=0.076 A for atomic coordinates and ESU=0.05 A for Cu---ligand bond
lengths, respectively. The auracyanin B molecule has a standard cupredoxin fold.
With the exception of an additional N-terminal strand, the molecule is very
similar to that of the bacterial cupredoxin, azurin. As in other cupredoxins,
one of the Cu ligands lies on strand 4 of the polypeptide, and the other three
lie along a large loop between strands 7 and 8. The Cu site geometry is
discussed with reference to the amino acid spacing between the latter three
ligands. The crystallographically characterized Cu-binding domain of auracyanin
B is probably tethered to the periplasmic side of the cytoplasmic membrane by an
N-terminal tail that exhibits significant sequence identity with known tethers
in several other membrane-associated electron-transfer proteins.
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Figure 1.
Figure 1. The photosynthetic electron-transfer cycle in
Chloroflexus aurantiacus (adapted from [Blankenship 1994]).
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Figure 4.
Figure 4. Schematic of the topology (polypeptide fold) of
CaAc-B, adapted from a similar diagram for azurin [Guss et al
1988]. The numerals identify the strands of the polypeptide
backbone. The broken line represents a largeloop at the southern
end of the auracyanin molecule, culminating in the additional
N-terminal strand (strand 0). The solid circlesrepresent the
locations of the four Cu-binding residues.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2001,
306,
47-67)
copyright 2001.
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