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HAMAP rule MF_01262

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General rule information [?]

Accession MF_01262
Dates 29-JUL-2005 (Created)
17-MAY-2023 (Last updated, Version 19)
Name CCA_bact_type2
Scope(s) Bacteria
Template(s) P06961 (CCA_ECOLI); Q7SIB1 (CCA_GEOSE); [ Recover all ]
Triggered by HAMAP; MF_01262 (Get profile general information and statistics)

Propagated annotation [?]

Identifier, protein and gene names [?]

Identifier CCA
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 Name=cca;

Comments [?]

FUNCTIONCatalyzes 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 Reaction=a tRNA precursor + ATP + 2 CTP = a tRNA with a 3' CCA end + 3 diphosphate; Xref=Rhea:RHEA:14433, Rhea:RHEA-COMP:10465, Rhea:RHEA- COMP:10468, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:37563, ChEBI:CHEBI:74896, ChEBI:CHEBI:83071; EC=;
CATALYTIC ACTIVITY Reaction=a tRNA with a 3' CCA end + ATP + 2 CTP = a tRNA with a 3' CCACCA end + 3 diphosphate; Xref=Rhea:RHEA:76235, Rhea:RHEA- COMP:10468, Rhea:RHEA-COMP:18655, ChEBI:CHEBI:30616, ChEBI:CHEBI:33019, ChEBI:CHEBI:37563, ChEBI:CHEBI:83071, ChEBI:CHEBI:195187; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:76236;
COFACTOR Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
MISCELLANEOUSA single active site specifically recognizes both ATP and CTP and is responsible for their addition.
SIMILARITYBelongs 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+)"
BINDING 23 23 /ligand="Mg(2+)"
BINDING 8 8 /ligand="ATP"
BINDING 8 8 /ligand="CTP"
BINDING 11 11 /ligand="ATP"
BINDING 11 11 /ligand="CTP"
BINDING 91 91 /ligand="ATP"
BINDING 91 91 /ligand="CTP"
BINDING 137 137 /ligand="ATP"
BINDING 137 137 /ligand="CTP"
BINDING 140 140 /ligand="ATP"
BINDING 140 140 /ligand="CTP"

Additional information [?]

Size range 360-419 amino acids
Related rules MF_01261
Fusion Nter: None Cter: 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.

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