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PDBsum entry 1vcn
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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 structures of ctp synthetase reveal ATP, Utp, And glutamine binding sites.
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Authors
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M.Goto,
R.Omi,
N.Nakagawa,
I.Miyahara,
K.Hirotsu.
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Ref.
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Structure, 2004,
12,
1413-1423.
[DOI no: ]
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PubMed id
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Abstract
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CTP synthetase (CTPs) catalyzes the last step in CTP biosynthesis, in which
ammonia generated at the glutaminase domain reacts with the ATP-phosphorylated
UTP at the synthetase domain to give CTP. Glutamine hydrolysis is active in the
presence of ATP and UTP and is stimulated by the addition of GTP. We report the
crystal structures of Thermus thermophilus HB8 CTPs alone, CTPs with 3SO4(2-),
and CTPs with glutamine. The enzyme is folded into a homotetramer with a
cross-shaped structure. Based on the binding mode of sulfate anions to the
synthetase site, ATP and UTP are computer modeled into CTPs with a geometry
favorable for the reaction. Glutamine bound to the glutaminase domain is
situated next to the triad of Glu-His-Cys as a catalyst and a water molecule.
Structural information provides an insight into the conformational changes
associated with the binding of ATP and UTP and the formation of the GTP binding
site.
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Figure 8.
Figure 8. Putative Conformational Change upon Binding of
ATP and UTPThe glutaminase domain (brown) is rotated toward the
synthetase domain (blue) on the graphics to form a computer
model of the compact molecule in the closed form. The consensus
sequence (green) specific for GTP on the glutaminase domain
approaches that (green) on the synthetase domain to form a
binding site for GTP. ATP and UTP modeled into the closed form
are drawn in red.
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The above figure is
reprinted
by permission from Cell Press:
Structure
(2004,
12,
1413-1423)
copyright 2004.
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