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PDBsum entry 1j4j
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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 tabtoxin resistance protein complexed with acetyl coenzyme a reveals the mechanism for beta-Lactam acetylation.
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Authors
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H.He,
Y.Ding,
M.Bartlam,
F.Sun,
Y.Le,
X.Qin,
H.Tang,
R.Zhang,
A.Joachimiak,
J.Liu,
N.Zhao,
Z.Rao.
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Ref.
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J Mol Biol, 2003,
325,
1019-1030.
[DOI no: ]
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PubMed id
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Abstract
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Tabtoxin resistance protein (TTR) is an enzyme that renders tabtoxin-producing
pathogens, such as Pseudomonas syringae, tolerant to their own phytotoxins.
Here, we report the crystal structure of TTR complexed with its natural
cofactor, acetyl coenzyme A (AcCoA), to 1.55A resolution. The binary complex
forms a characteristic "V" shape for substrate binding and contains
the four motifs conserved in the GCN5-related N-acetyltransferase (GNAT)
superfamily, which also includes the histone acetyltransferases (HATs). A
single-step mechanism is proposed to explain the function of three conserved
residues, Glu92, Asp130 and Tyr141, in catalyzing the acetyl group transfer to
its substrate. We also report that TTR possesses HAT activity and suggest an
evolutionary relationship between TTR and other GNAT members.
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Figure 3.
Figure 3. AcCoA recognition and binding. (a) A stereo view
of an |F[o]| -|F[c]| difference map calculated in the absence of
AcCoA. The map is contoured at 2s. (b) The side-chain
interactions between TTR and AcCoA. Hydrogen bonds are marked by
green arrows and hydrophobic interactions are indicated in red.
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Figure 4.
Figure 4. (a) A stereo view of the catalytic site showing
interactions between TTR and both AcCoA and the tightly bound
water molecule; GRASP surfaces showing the AcCoA-binding pocket
viewed from the front (b) and back (c), respectively (color
coded according to electrostatic potential: blue corresponds to
20k[B]T; white, 0k[B]T; and red, -20k[B]T). (b) The front view,
with two polar regions inside the hydrophobic-binding pocket.
The positive region indicated in blue corresponds to residue
Lys95 and the negative region in red corresponds to residues
Glu92 and Asp130. (c) The back view.
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2003,
325,
1019-1030)
copyright 2003.
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