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PDBsum entry 1hux
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Metal binding protein
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PDB id
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1hux
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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 the acidaminococcus fermentans 2-Hydroxyglutaryl-Coa dehydratase component a.
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Authors
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K.P.Locher,
M.Hans,
A.P.Yeh,
B.Schmid,
W.Buckel,
D.C.Rees.
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Ref.
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J Mol Biol, 2001,
307,
297-308.
[DOI no: ]
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PubMed id
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Abstract
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Acidaminococcus fermentans degrades glutamate via the hydroxyglutarate pathway,
which involves the syn-elimination of water from (R)-2-hydroxyglutaryl-CoA in a
key reaction of the pathway. This anaerobic process is catalyzed by
2-hydroxyglutaryl-CoA dehydratase, an enzyme with two components (A and D) that
reversibly associate during reaction cycles. Component A (CompA), a homodimeric
cluster and uses the
hydrolysis of ATP to deliver an electron to the dehydratase component (CompD),
where the electron is used catalytically. The structure of the extremely
oxygen-sensitive CompA protein was solved by X-ray crystallography to 3 A
resolution. The protein was found to be a member of the actin fold family,
revealing a similar architecture and nucleotide-binding site. The key
differences between CompA and other members of the actin fold family are: (i)
the presence of a cluster binding segment, the "cluster helix"; (ii)
cluster; and (iii) the location of the homodimer interface, which
involves the bridging cluster. Possible reaction mechanisms are discussed in
light of the close structural similarity to members of the actin-fold family and
the functional similarity to the nitrogenase Fe- protein.
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Figure 2.
Figure 2. Superposition of CompA (monomer A) and hsc70 (PDB
entry 3HSC). A stereo view of a ribbon representation is shown,
with CompA and Hsc70 in purple and yellow, respectively. The
[4Fe-4S] cluster is shown as a CPK model, with sulfur and iron
in green and red. The superposition of these structures was
performed using 182 C^a atoms with a r.m.s. deviation of 2.3
Å. The following segments were superimposed: CompA (Hsc70)
4-21 (5-22), 31-37 (37-43), 39-56 (122-139), 61-66 (141-146),
71-74 (161-164), 76-89 (169-182), 90-93 (180-183), 98-115
(195-212), 118-125 (219-226), 131-141 (229-239), 145-150
(270-275), 186-190 (300-304), 194-207 (308-321), 209-235
(331-357), 236-239 (359-362), 241-258 (364-381).
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Figure 3.
Figure 3. Stereoviews of the homodimeric CompA protein.
Ribbon representations are shown from "top" and "side" views,
with monomer A in green and cyan and monomer B in purple and
dark red. ADP is shown in ball-and-stick, and the [4Fe-4S]
cluster is shown as a CPK model (red and yellow spheres for iron
and sulfur, respectively). The top view is along the
non-crystallographic 2-fold symmetry axis, whereas the side view
is turned by 90° to the left, with the 2-fold lying
horizontally in the plane of the paper. The molecule was
additionally rotated a few degrees around the 2-fold axis in
this view. The bottom view is shown in CPK representation, with
the four sulfur atoms of the cluster shown in green.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2001,
307,
297-308)
copyright 2001.
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