HAMAP rule MF

Accession	MF_01261
Dates	29-JUL-2005 (Created) 17-MAY-2023 (Last updated, Version 24)

Name	CCA_bact_type1

Scope

Bacteria; Pseudomonadota

Templates

P06961 (CCA_ECOLI); Q7SIB1 (CCA_GEOSE): [Recover all]

Triggered by

HAMAP; MF_01261 (Get profile general information and statistics)

Identifier

CCA

Protein name

RecName:		Full=Multifunctional CCA protein;
Includes:
	RecName:		Full=CCA-adding enzyme;
			EC 2.7.7.72;
	AltName:		Full=CCA tRNA nucleotidyltransferase;
	AltName:		Full=tRNA CCA-pyrophosphorylase;
	AltName:		Full=tRNA adenylyl-/cytidylyl-transferase;
	AltName:		Full=tRNA nucleotidyltransferase;
	AltName:		Full=tRNA-NT;
Includes:
	RecName:		Full=2'-nucleotidase;
			EC 3.1.3.-;
Includes:
	RecName:		Full=2',3'-cyclic phosphodiesterase;
			EC 3.1.4.-;
Includes:
	RecName:		Full=Phosphatase;
			EC 3.1.3.-;

Gene name

cca

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 EC 2.7.7.72
	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+) Note: Magnesium is required for nucleotidyltransferase activity.
	Ni(2+) Note: Nickel for phosphatase activity.
Subunit	Monomer. Can also form homodimers and oligomers.
Domain	Comprises two domains: an N-terminal domain containing the nucleotidyltransferase activity and a C-terminal HD domain associated with both phosphodiesterase and phosphatase activities.
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 1 subfamily.

ATP-binding
Hydrolase
Magnesium
Metal-binding
Multifunctional enzyme
Nickel
Nucleotide-binding
Nucleotidyltransferase
RNA repair
RNA-binding
Transferase
tRNA processing

GO:0000049; Molecular function: tRNA binding.
GO:0000166; Molecular function: nucleotide binding.
GO:0000287; Molecular function: magnesium ion binding.
GO:0004112; Molecular function: cyclic-nucleotide phosphodiesterase activity.
GO:0004810; Molecular function: CCA tRNA nucleotidyltransferase activity.
GO:0005524; Molecular function: ATP binding.
GO:0016791; Molecular function: phosphatase activity.
GO:0001680; Biological process: tRNA 3'-terminal CCA addition.

Pfam	PF01966; HD; 1;
	PF01743; PolyA_pol; 1;
PROSITE	PS51831; HD; 1; trigger=PRU01175;

From: CCA_ECOLI (P06961)

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

Size range	368-429 amino acids
Related rules	MF_01262 (CCA)
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). 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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HAMAP rule MF_01261