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HAMAP rule MF_01262

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General rule information [?]

Accession MF_01262
Dates 29-JUL-2005 (Created)
26-JAN-2023 (Last updated, Version 17)
Name CCA_bact_type2
Bacteria; Pseudomonadota
Templates P06961 (CCA_ECOLI); Q7SIB1 (CCA_GEOSE): [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.
Catalytic activity RHEA:14433: a tRNA precursor + ATP + 2 CTP = a tRNA with a 3' CCA end + 3 diphosphate
Cofactor Mg(2+)
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. Bacterial CCA-adding enzyme type 2 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 PF01743; PolyA_pol; 1;

Features [?]

From: CCA_BUCAI (P57169)
Key     From     To       Description   Tag   Condition   FTGroup
BINDING     21     21       /ligand="Mg(2+)" /ligand_id="ChEBI:CHEBI:18420     [DE]  
BINDING     23     23       /ligand="Mg(2+)" /ligand_id="ChEBI:CHEBI:18420     D  
BINDING     8     8       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     G  
BINDING     8     8       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     G  
BINDING     11     11       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     R  
BINDING     11     11       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     R  
BINDING     91     91       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     R  
BINDING     91     91       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     R  
BINDING     137     137       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     R  
BINDING     137     137       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     R  
BINDING     140     140       /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616     R  
BINDING     140     140       /ligand="CTP" /ligand_id="ChEBI:CHEBI:37563     R  

Additional information [?]

Size range 360-419 amino acids
Related rules MF_01261 (CCA supersedes the current rule)
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). There is no characterized protein in this subfamily. The closest sequence homologs are from type 1 subfamily (MF_01261), which is also a proteobacterial family (E.coli is characterized) but which contains an HD domain associated with phosphohydrolase activities. As the type 2 subfamily does not contain such a domain, it should not possess phosphohydrolase activities. FT lines are propagated from G.stearothermophilus CCA-adding enzyme (type 3 subfamily, MF_01263) whose X-ray structure is known.