Crystal Structures of an Archaeal Class I CCA-Adding Enzyme and Its Nucleotide Complexes

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.189 

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Crystal structures of an archaeal class I CCA-adding enzyme and its nucleotide complexes

Xiong, Y.Li, F.Wang, J.Weiner, A.M.Steitz, T.A.

(2003) Mol Cell 12: 1165-1172

  • DOI: https://doi.org/10.1016/s1097-2765(03)00440-4
  • Primary Citation of Related Structures:  
    1R89, 1R8A, 1R8B, 1R8C

  • PubMed Abstract: 

    CCA-adding enzymes catalyze the addition of CCA onto the 3' terminus of immature tRNAs without using a nucleic acid template and have been divided into two classes based on their amino acid sequences. We have determined the crystal structures of a class I CCA-adding enzyme from Archeoglobus fulgidus (AfCCA) and its complexes with ATP, CTP, or UTP. Although it and the class II bacterial Bacillus stearothermophilus CCA enzyme (BstCCA) have similar dimensions and domain architectures (head, neck, body, and tail), only the polymerase domain is structurally homologous. Moreover, the relative orientation of the head domain with respect to the body and tail domains, which appear likely to bind tRNA, differs significantly between the two enzyme classes. Unlike the class II BstCCA, this enzyme binds nucleotides nonspecifically in the absence of bound tRNA. The shape and electrostatic charge distribution of the AfCCA enzyme suggests a model for tRNA binding that accounts for the phosphates that are protected from chemical modification by tRNA binding to AfCCA. The structures of the AfCCA enzyme and the eukaryotic poly(A) polymerase are very similar, implying a close evolutionary relationship between them.

  • Organizational Affiliation

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

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
tRNA nucleotidyltransferase437Archaeoglobus fulgidusMutation(s): 0 
Gene Names: CCAAF2156
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
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.189 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 86.453α = 90
b = 78.726β = 98.03
c = 77.396γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-12-16
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Derived calculations, Version format compliance
  • Version 1.3: 2024-02-14
    Changes: Data collection, Database references, Derived calculations