HAMAP logo

HAMAP rule MF_01264

Send feedback

General rule information [?]

Accession MF_01264
Dates 29-JUL-2005 (Created)
1-JUN-2023 (Last updated, Version 19)
Name CCA_arch
Templates O28126 (CCA_ARCFU); P77978 (CCA_SACSH); Q58511 (CCA_METJA): [Recover all]

Propagated annotation [?]

Identifier, protein and gene names [?]

Protein name
RecName: Full=CCA-adding enzyme;
AltName: Full=CCA tRNA nucleotidyltransferase;
AltName: Full=tRNA CCA-pyrophosphorylase;
AltName: Full=tRNA adenylyl-/cytidylyl- transferase;
AltName: Full=tRNA nucleotidyltransferase;
AltName: Full=tRNA-NT;
Gene name

Comments [?]

Function Catalyzes the addition and repair of the essential 3'-terminal CCA sequence in tRNAs without using a nucleic acid template. Adds these three nucleotides in the order of C, C, and A to the tRNA nucleotide-73, using CTP and ATP as substrates and producing inorganic pyrophosphate. tRNA 3'-terminal CCA addition is required both for tRNA processing and repair. Also involved in tRNA surveillance by mediating tandem CCA addition to generate a CCACCA at the 3' terminus of unstable tRNAs. While stable tRNAs receive only 3'-terminal CCA, unstable tRNAs are marked with CCACCA and rapidly degraded.
Catalytic activity RHEA:14433: a tRNA precursor + ATP + 2 CTP = a tRNA with a 3' CCA end + 3 diphosphate
RHEA:76235: a tRNA with a 3' CCA end + ATP + 2 CTP = a tRNA with a 3' CCACCA end + 3 diphosphate
PhysiologicalDirection=left-to-right (RHEA:76236)
Cofactor Mg(2+)
Subunit Homodimer.
Miscellaneous A single active site specifically recognizes both ATP and CTP and is responsible for their addition.
Similarity Belongs to the tRNA nucleotidyltransferase/poly(A) polymerase family. Archaeal CCA-adding enzyme subfamily.

Keywords [?]

Gene Ontology [?]

GO:0000049; Molecular function: tRNA binding.
GO:0000166; Molecular function: nucleotide binding.
GO:0000287; Molecular function: magnesium ion binding.
GO:0004810; Molecular function: CCA tRNA nucleotidyltransferase activity.
GO:0005524; Molecular function: ATP binding.
GO:0001680; Biological process: tRNA 3'-terminal CCA addition.

Cross-references [?]

Pfam PF01909; NTP_transf_2; 1;
PF09249; tRNA_NucTransf2; 1;
PIRSF PIRSF005335; CCA_arch; 1;
NCBIfam TIGR03671; Cca_archaeal; 1;

Features [?]

From: CCA_ARCFU (O28126)
Key     From     To       Description   Tag   Condition   FTGroup
BINDING     59     59       /ligand="Mg(2+)" /ligand_id="ChEBI:CHEBI:18420     [DE]  
BINDING     61     61       /ligand="Mg(2+)" /ligand_id="ChEBI:CHEBI:18420     D  
BINDING     110     110       /ligand="Mg(2+)" /ligand_id="ChEBI:CHEBI:18420     [DE]  
BINDING     47     47       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     S  
BINDING     47     47       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     S  
BINDING     50     50       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     [RK]  
BINDING     50     50       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     [RK]  
BINDING     133     133       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     H  
BINDING     133     133       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     H  
BINDING     152     152       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     K  
BINDING     152     152       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     K  
BINDING     161     161       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     Y  
BINDING     161     161       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     Y  

Additional information [?]

Size range 392-485 amino acids
Related rules None
Fusion None
Comments The CCA-adding enzyme family consists of 4 different subfamilies: 3 bacterial subfamilies (MF_01261, MF_01262 and MF_01263) and 1 archaeal subfamily (MF_01264).