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PDBsum entry 1erj
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Transcription inhibitor
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PDB id
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1erj
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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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Structure of the c-Terminal domain of tup1, A corepressor of transcription in yeast.
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Authors
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E.R.Sprague,
M.J.Redd,
A.D.Johnson,
C.Wolberger.
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Ref.
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EMBO J, 2000,
19,
3016-3027.
[DOI no: ]
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PubMed id
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Abstract
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The Tup1-Ssn6 corepressor complex regulates the expression of several sets of
genes, including genes that specify mating type in the yeast Saccharomyces
cerevisiae. Repression of mating-type genes occurs when Tup1-Ssn6 is brought to
the DNA by the Matalpha2 DNA-binding protein and assembled upstream of a- and
haploid-specific genes. We have determined the 2.3 A X-ray crystal structure of
the C-terminal domain of Tup1 (accesion No. 1ERJ), a 43 kDa fragment that
contains seven copies of the WD40 sequence motif and binds to the Matalpha2
protein. Moreover, this portion of the protein can partially substitute for
full-length Tup1 in bringing about transcriptional repression. The structure
reveals a seven-bladed beta propeller with an N-terminal subdomain that is
anchored to the side of the propeller and extends the beta sheet of one of the
blades. Point mutations in Tup1 that specifically affect the Tup1-Matalpha2
interaction cluster on one surface of the propeller. We identified regions of
Tup1 that are conserved among the fungal Tup1 homologs and may be important in
protein-protein interactions with additional components of the Tup1-mediated
repression pathways.
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Figure 2.
Figure 2 Packing of the N-terminal fragment against the
propeller. (A) Extended  sheet
formed by blade 6 and strands n1 and n2 from the N-terminal
fragment. Hydrogen bonds are indicated with dashed lines. (B)
Stereoview of contacts between the N-terminal fragment
(283–331) and the propeller. Side chain and backbone atoms are
superimposed on the C[  ]trace.
Some side chain labels were omitted for clarity. The approximate
boundaries of each blade are shown in different colors (blade 5,
light green; blade 6, blue; blade 7, red; N-terminal fragment,
gray). This figure was generated with RIBBONS (Carson, 1997).
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Figure 3.
Figure 3 (A) Superposition of all seven blades of Tup1. The C[
]backbone
for each of the seven blades was aligned with respect to strands
3B and 3C. The four conserved side chains involved in the
intrablade hydrogen-bonding network, referred to as the
structural tetrad, are shown for blade 3 as ball-and-stick
models colored according to atom type and hydrogen bonds are
indicated with dashed lines. A representative blade from G ,
blade 4, is shown for reference. Blade 1, light green; blade 2,
red; blade 3, green; blade 4, purple; blade 5, pink; blade 6,
cyan; blade 7, orange; G ,
brown. (B) Superposition of the WD40 propellers. The C[ ]backbones
for G (blue;
1TBG) and Tup1 (yellow), which align with an r.m.s.d. of 1.3
Å, are shown in the same view as Figure 1A and labeled.
Least-squares alignments for (A) and (B) were done in O (Jones
et al., 1991) and figures generated with RIBBONS (Carson, 1997).
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The above figures are
reprinted
from an Open Access publication published by Macmillan Publishers Ltd:
EMBO J
(2000,
19,
3016-3027)
copyright 2000.
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