Biological Assembly 1  

 3D View: Structure | Electron Density | Validation Report

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 102.45 kDa 
• Atom Count: 5570 
• Modelled Residue Count: 688 
• Deposited Residue Count: 896 
• Unique protein chains: 1

1OU5

Crystal structure of human CCA-adding enzyme

• DOI: 10.2210/pdb1OU5/pdb

• Classification: TRANSLATION, TRANSFERASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2003-03-24 Released: 2003-05-06 
• Deposition Author(s): Augustin, M.A., Reichert, A.S., Betat, H., Huber, R., Moerl, M., Steegborn, C.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.40 Å
• R-Value Free: 0.318 
• R-Value Work: 0.278 
• R-Value Observed: 0.282 

Literature

Crystal Structure of the Human CCA-adding Enzyme: Insights into Template-independent Polymerization

Augustin, M.A., Reichert, A.S., Betat, H., Huber, R., Moerl, M., Steegborn, C.

(2003) J Mol Biol 328: 985-994

• PubMed: 12729736 
• DOI: 10.1016/s0022-2836(03)00381-4
• Primary Citation of Related Structures:  
  1OU5


• PubMed Abstract: 
  

All tRNA molecules carry the invariant sequence CCA at their 3'-terminus for amino acid attachment. The post-transcriptional addition of CCA is carried out by ATP(CTP):tRNA nucleotidyltransferase, also called CCase. This enzyme catalyses a unique template-independent but sequence-specific nucleotide polymerization reaction. In order to reveal the molecular mechanism of this activity, we solved the crystal structure of human CCase by single isomorphous replacement. The structure reveals a four domain architecture with a cluster of conserved residues forming a positively charged cleft between the first two domains. Structural homology of the N-terminal CCase domain to other nucleotidyltransferases could be exploited for modeling a tRNA-substrate complex. The model places the tRNA 3'-end into the N-terminal nucleotidyltransferase site, close to a patch of conserved residues that provide the binding sites for CTP and ATP. Based on our results, we introduce a corkscrew model for CCA addition that includes a fixed active site and a traveling tRNA-binding region formed by flexible parts of the protein.

---

Organizational Affiliation: 

Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, Am Klopferspitz 18A, D-82152 Martinsried, Germany. [e-mail]

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
tRNA CCA-adding enzyme	A, B	448	Homo sapiens	Mutation(s): 0  Gene Names: hMtCCA, TRNT1, CGI-47 EC: 2.7.7.72
UniProt & NIH Common Fund Data Resources
Find proteins for Q96Q11 (Homo sapiens) Explore Q96Q11  Go to UniProtKB:  Q96Q11
PHAROS:  Q96Q11 GTEx:  ENSG00000072756

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.40 Å
• R-Value Free: 0.318 
• R-Value Work: 0.278 
• R-Value Observed: 0.282 
• Space Group: P 3₂ 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 102.52	α = 90
b = 102.52	β = 90
c = 206.658	γ = 120

Software Package:

Software Name	Purpose
MOSFLM	data reduction
SCALA	data scaling
SHARP	phasing
REFMAC	refinement
CCP4	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2003-03-24 
• Released Date: 2003-05-06 
Deposition Author(s): Augustin, M.A., Reichert, A.S., Betat, H., Huber, R., Moerl, M., Steegborn, C.

Revision History  

• Version 1.0: 2003-05-06
  Type: Initial release
  
• Version 1.1: 2008-04-29
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2017-10-11
  Changes: Advisory, Refinement description