CCA-adding enzyme

Details

Name
CCA-adding enzyme
Kind
protein
Synonyms
  • 2.7.7.72
  • CCA tRNA nucleotidyltransferase
  • tRNA adenylyl-/cytidylyl- transferase
  • tRNA CCA-pyrophosphorylase
  • tRNA nucleotidyltransferase
  • tRNA-NT
Gene Name
cca
UniProtKB Entry
Q7SIB1Swiss-Prot
Organism
Geobacillus stearothermophilus
NCBI Taxonomy ID
1422
Amino acid sequence
>lcl|BSEQ0022032|CCA-adding enzyme
MKPPFQEALGIIQQLKQHGYDAYFVGGAVRDLLLGRPIGDVDIATSALPEDVMAIFPKTI
DVGSKHGTVVVVHKGKAYEVTTFKTDGDYEDYRRPESVTFVRSLEEDLKRRDFTMNAIAM
DEYGTIIDPFGGREAIRRRIIRTVGEAEKRFREDALRMMRAVRFVSELGFALAPDTEQAI
VQNAPLLAHISVERMTMEMEKLLGGPFAARALPLLAETGLNAYLPGLAGKEKQLRLAAAY
RWPWLAAREERWALLCHALGVQESRPFLRAWKLPNKVVDEAGAILTALADIPRPEAWTNE
QLFSAGLERALSVETVRAAFTGAPPGPWHEKLRRRFASLPIKTKGELAVNGKDVIEWVGK
PAGPWVKEALDAIWRAVVNGEVENEKERIYAWLMERNRTREKNC
Number of residues
404
Molecular Weight
45368.875
Theoretical pI
8.61
GO Classification
Functions
ATP / ATP binding / CTP / magnesium ion binding / tRNA binding / tRNA cytidylyltransferase activity
Processes
RNA repair / tRNA 3'-terminal CCA addition
General 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 (By similarity). The structural flexibility of RNA controls the choice between CCA versus CCACCA addition: following the first CCA addition cycle, nucleotide-binding to the active site triggers a clockwise screw motion, producing torque on the RNA. This ejects stable RNAs, whereas unstable RNAs are refolded while bound to the enzyme and subjected to a second CCA catalytic cycle (By similarity).
Specific Function
ATP binding
Pfam Domain Function
Signal Regions
Not Available
Transmembrane Regions
Not Available
Cellular Location
Cytoplasmic
Gene sequence
Not Available
Chromosome Location
Not Available
Locus
Not Available
External Identifiers
ResourceLink
UniProtKB IDQ7SIB1
UniProtKB Entry NameCCA_GEOSE
PDB ID(s)1MIV, 1MIW, 1MIY
General References
  1. Li F, Xiong Y, Wang J, Cho HD, Tomita K, Weiner AM, Steitz TA: Crystal structures of the Bacillus stearothermophilus CCA-adding enzyme and its complexes with ATP or CTP. Cell. 2002 Dec 13;111(6):815-24. [Article]

Associated Data

Drug Relations
DrugDrug groupPharmacological action?TypeActionsDetails
Cytidine-5'-TriphosphateexperimentalunknowntargetDetails