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PDBsum entry 3e1k
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Transcription
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PDB id
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3e1k
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Contents |
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(+ 2 more)
395 a.a.
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(+ 2 more)
14 a.a.
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References listed in PDB file
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Key reference
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Title
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The interaction between an acidic transcriptional activator and its inhibitor: the molecular basis of gal4p recognition by gal80p.
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Authors
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J.B.Thoden,
L.A.Ryan,
R.J.Reece,
H.M.Holden.
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Ref.
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J Biol Chem, 2008,
283,
30266-30272.
[DOI no: ]
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PubMed id
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Abstract
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The GAL genes, which encode the enzymes required for normal galactose metabolism
in yeast, are transcriptionally regulated by three proteins: Gal4p, an
activator; Gal80p, an inhibitor; and Gal3p, a galactose sensor. These proteins
control the switch between inert and active gene expression. The transcriptional
activation function of Gal4p is rendered inactive in the presence of Gal80p.
Here we present the three-dimensional structure of a complex between the acidic
activation domain of Gal4p and Gal80p. The transactivation domain initiates with
an extended region of polypeptide chain followed by two turns of an amphipathic
alpha-helix. It fits into and across a deep cleft within the Gal80p dimer with
the protein-protein interface defined primarily by hydrophobic interactions. A
disordered loop in the apo-Gal80p structure (Asp-309 to Ser-316) becomes
well-defined upon binding of the transactivation domain. This investigation
provides a new molecular scaffold for understanding previous biochemical and
genetic studies.
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Figure 2.
The interaction between the Gal4p TAD and Gal80p. A, stereo
view of unbiased electron density corresponding to the bound
Gal4p TAD before model building. The “averaged” electron
density map was contoured at ∼1σ. A polyglycine chain,
displayed with carbons, nitrogens, and oxygens in slate, blue,
and red, respectively, was positioned into the map for the sake
of clarity in viewing the electron density. The Asp-309/Ser-316
loop that becomes ordered upon Gal4p binding is highlighted in
gold. B, close-up stereo view of the Gal80p TAD binding region.
Those residues of Gal80p lying within ∼5 Å of the Gal4p
TAD (slate) are displayed in gold. This figure and Figs. 3, 4,
5, 6 were prepared with the software package PyMOL (34).
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Figure 6.
The potential interaction between the K. lactis Gal80p, the
K. lactis Gal4p activation peptide, and NAD. A, Gal80p monomer
showing the location of the Gal4p peptide (slate) and the
modeled NAD (green). B, close-up stereo view of the Gal80p
region (white ribbon and gold bonds) surrounding the modeled NAD
(green) and the observed Gal4p peptide (slate). Glu-98 in the K.
lactis Gal80p is a serine residue in the S. cerevisiae Gal80p.
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The above figures are
reprinted
from an Open Access publication published by the ASBMB:
J Biol Chem
(2008,
283,
30266-30272)
copyright 2008.
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