3OVA

How the CCA-adding Enzyme Selects Adenine over Cytosine in Position 76 of tRNA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.98 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.216 

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Literature

How the CCA-Adding Enzyme Selects Adenine over Cytosine at Position 76 of tRNA.

Pan, B.Xiong, Y.Steitz, T.A.

(2010) Science 330: 937-940

  • DOI: 10.1126/science.1194985
  • Primary Citation of Related Structures:  
    3OUY, 3OV7, 3OVA, 3OVB, 3OVS

  • PubMed Abstract: 
  • CCA-adding enzymes [ATP(CTP):tRNA nucleotidyltransferases] add CCA onto the 3' end of transfer RNA (tRNA) precursors without using a nucleic acid template. Although the mechanism by which cytosine (C) is selected at position 75 of tRNA has been established, the mechanism by which adenine (A) is selected at position 76 remains elusive ...

    CCA-adding enzymes [ATP(CTP):tRNA nucleotidyltransferases] add CCA onto the 3' end of transfer RNA (tRNA) precursors without using a nucleic acid template. Although the mechanism by which cytosine (C) is selected at position 75 of tRNA has been established, the mechanism by which adenine (A) is selected at position 76 remains elusive. Here, we report five cocrystal structures of the enzyme complexed with both a tRNA mimic and nucleoside triphosphates under catalytically active conditions. These structures suggest that adenosine 5'-monophosphate is incorporated onto the A76 position of the tRNA via a carboxylate-assisted, one-metal-ion mechanism with aspartate 110 functioning as a general base. The discrimination against incorporation of cytidine 5'-triphosphate (CTP) at position 76 arises from improper placement of the α phosphate of the incoming CTP, which results from the interaction of C with arginine 224 and prevents the nucleophilic attack by the 3' hydroxyl group of cytidine75.


    Organizational Affiliation

    Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.



Macromolecules

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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CCA-Adding EnzymeA435Archaeoglobus fulgidusMutation(s): 0 
EC: 2.7.7.25 (PDB Primary Data), 2.7.7.21 (PDB Primary Data), 2.7.7.72 (UniProt)
UniProt
Find proteins for O28126 (Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16))
Explore O28126 
Go to UniProtKB:  O28126
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO28126
Protein Feature View
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  • Reference Sequence
Find similar nucleic acids by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChainsLengthOrganismImage
RNA (34-MER)B [auth C]34N/A
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
APC
Query on APC

Download Ideal Coordinates CCD File 
C [auth A]DIPHOSPHOMETHYLPHOSPHONIC ACID ADENOSYL ESTER
C11 H18 N5 O12 P3
CAWZRIXWFRFUQB-IOSLPCCCSA-N
 Ligand Interaction
SO4
Query on SO4

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D [auth A]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
EDO
Query on EDO

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F [auth A],
G [auth A],
H [auth A]
1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

Download Ideal Coordinates CCD File 
E [auth A]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.98 Å
  • R-Value Free: 0.244 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.216 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.942α = 90
b = 57.942β = 90
c = 427.945γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASESphasing
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-12-01
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance