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PDBsum entry 2hes
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Biosynthetic protein
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PDB id
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2hes
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References listed in PDB file
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Key reference
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Title
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Structure of the yeast wd40 domain protein cia1, A component acting late in iron-Sulfur protein biogenesis.
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Authors
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V.Srinivasan,
D.J.Netz,
H.Webert,
J.Mascarenhas,
A.J.Pierik,
H.Michel,
R.Lill.
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Ref.
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Structure, 2007,
15,
1246-1257.
[DOI no: ]
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PubMed id
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Abstract
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The WD40-repeat protein Cia1 is an essential, conserved member of the cytosolic
iron-sulfur (Fe/S) protein assembly (CIA) machinery in eukaryotes. Here, we
report the crystal structure of Saccharomyces cerevisiae Cia1 to 1.7 A
resolution. The structure folds into a beta propeller with seven blades pseudo
symmetrically arranged around a central axis. Structure-based sequence alignment
of Cia1 proteins shows that the WD40 propeller core elements are highly
conserved. Site-directed mutagenesis of amino acid residues in loop regions with
high solvent accessibility identified that the conserved top surface residue
R127 performs a critical function: the R127 mutant cells grew slowly and were
impaired in cytosolic Fe/S protein assembly. Human Ciao1, which reportedly
interacts with the Wilms' tumor suppressor, WT1, is structurally similar to
yeast Cia1. We show that Ciao1 can functionally replace Cia1 and support
cytosolic Fe/S protein biogenesis. Hence, our structural and biochemical studies
indicate the conservation of Cia1 function in eukaryotes.
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Figure 3.
Figure 3. Comparison of the 3D Structures of Cia1 and Gβ
Superposition of the Cα coordinates of Gβ (PDB code:
1TBG) and the crystal structure coordinates of yeast Cia1. The
superposition was computed by using the least-squares algorithm
in the program O (Jones et al., 1991).
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Figure 4.
Figure 4. Amino Acid Sequence Conservation at the Surface of
Cia1
(A) Location of the residues exchanged by
site-directed mutagenesis (see Figure 2) from a top view looking
down the central propeller axis and a bottom view obtained by
rotation of 180°.
(B) Representation of the
conservation of amino acid residues in Cia1 from top and bottom
views. The degree of conservation is indicated by the intensity
of the red color. The position of the crucial residue R127 is
highlighted in purple. Amino acid sequences (67 in total) of
Cia1 homologs were collected from various databases by blastp
and tblastn searches. After CLUSTAL W alignment (Thompson et
al., 1994), the degree of conservation was calculated by using
the program ConSurf (Landau et al., 2005). Red, orange, and
light-orange colors correspond to residues with a conservation
score above the 9^th, between the 9^th and 8^th, and between the
8^th and 7^th decile, respectively.
(C) Same as in (B), but
for the side views. The yellow markers in (B) and (C) indicate
the respective sides of the Cia1 structure. The figure was
prepared by using PyMol (http://www.pymol.org) (DeLano, 2002).
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The above figures are
reprinted
by permission from Cell Press:
Structure
(2007,
15,
1246-1257)
copyright 2007.
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