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PDBsum entry 1miv
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Translation, transferase
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PDB id
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1miv
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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 the bacillus stearothermophilus cca-Adding enzyme and its complexes with ATP or ctp.
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Authors
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F.Li,
Y.Xiong,
J.Wang,
H.D.Cho,
K.Tomita,
A.M.Weiner,
T.A.Steitz.
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Ref.
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Cell, 2002,
111,
815-824.
[DOI no: ]
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PubMed id
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Abstract
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CCA-adding enzymes polymerize CCA onto the 3' terminus of immature tRNAs without
using a nucleic acid template. The 3.0 A resolution crystal structures of the
CCA-adding enzyme from Bacillus stearothermophilus and its complexes with ATP or
CTP reveal a seahorse-shaped subunit consisting of four domains: head, neck,
body, and tail. The head is structurally homologous to the palm domain of DNA
polymerase beta but has additional structural features and functions. The neck,
body, and tail represent new protein folding motifs. The neck provides a
specific template for the incoming ATP or CTP, whereas the body and tail may
bind tRNA. Each subunit has one active site capable of switching its base
specificity between ATP and CTP, an important component of the CCA-adding
mechanism.
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Figure 3.
Figure 3. Important Interactions between ATP and Conserved
Residues of BstCCA that Confer Specificity for the Base, the
Ribose, and the TriphosphateThe five conserved sequence motifs,
as explained in detail in Figure 5, are: A (magenta), B (light
green), C (dark green), D (yellow), and E (brown).
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Figure 4.
Figure 4. Base-Specific Interactions between BstCCA and ATP
or CTP(A) Interactions between the carboxylate of D154 and the
guanidinium group of R157 of BstCCA and ATP.(B) Interaction
between D154 and R157 of BstCCA and CTP. The position of the
guanidinium group of R157 is changed to be complementary to C
while D154 interacts with the N4 of C in much the same way as it
interacts with the N6 of A.
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The above figures are
reprinted
by permission from Cell Press:
Cell
(2002,
111,
815-824)
copyright 2002.
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