Protein: CCA-adding enzyme (P77978)
Organism: Saccharolobus shibatae (strain ATCC 51178 / DSM 5389 / JCM 8931 / NBRC
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. 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 (By similarity). This ejects stable RNAs, whereas unstable RNAs are refolded while bound to the enzyme and subjected to a second CCA catalytic cycle (By similarity)
Sequence: MIEEEVLKIIKPTEEDKKGIEKVLEIIRERLNKLDFEVEGSFRKGTWLRQDTDVDVFVFYPKDVGKEYLERNALNDIINRIKDLDYTLAYAEHPYVIVNINNVEVDIVPALRVESGDRAITAVDRTPFHTKYVTSHLDERGKDEVRLLKRFMKGIGVYGAELKVQGFSGYATELLVIYYGSFRKVLEAASKWKHPIKIELTKPMRAFSEPLIIPDPVDPRRNVTAAVSLKNIATFSVAAKYYLKNPSMEFFFPSKKVEEKIKGDVLILRLNLDEKSSEDIIWGQIKRSVNKIERALKQSGFRVIDIQAWGDTSNIVIAVQLESKNIGQYYLNIGPQYYSETIDDFIQKNDNIWVGEDGRLYSIKERKEYNAEAIAKKNIVLKVKYNIESYWLQNTEDQQIMKFLRKTPTWLK
InterPro domains: - IPR006116: 2-5OAS/ClassI-CCAase, nucleotidyltransferase domain (domain) [12-136]
- IPR008229: tRNA nucleotidyltransferase, archaea (family) [1-412]
- IPR015329: tRNA nucleotidyltransferase, substrate binding (domain) [143-252]
- IPR043519: Nucleotidyltransferase superfamily (homologous_superfamily) [4-182]
- IPR048833: CCA-adding enzyme, C-terminal domain (domain) [275-380]
- IPR002934: Polymerase, nucleotidyl transferase domain (domain) [20-129]
- IPR011068: Nucleotidyltransferase, class I-like, C-terminal (homologous_superfamily) [238-411]
- IPR042090: tRNA nucleotidyltransferase, domain 2 (homologous_superfamily) [6-252]
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0003824 (catalytic activity), GO:0036094 (small molecule binding), GO:1901363 (heterocyclic compound binding), GO:0016740 (transferase activity), GO:0043167 (ion binding), GO:0097159 (organic cyclic compound binding), GO:0097367 (carbohydrate derivative binding), GO:1901265 (nucleoside phosphate binding), GO:0016772 (transferase activity, transferring phosphorus-containing groups), GO:0043168 (anion binding), GO:0000166 (nucleotide binding), GO:0032553 (ribonucleotide binding), GO:0035639 (purine ribonucleoside triphosphate binding), GO:0016779 (nucleotidyltransferase activity), GO:0032555 (purine ribonucleotide binding), GO:0017076 (purine nucleotide binding), GO:0005524 (ATP binding), GO:0005525 (GTP binding), GO:0019001 (guanyl nucleotide binding), GO:0032559 (adenyl ribonucleotide binding), GO:0070566 (adenylyltransferase activity), GO:0030554 (adenyl nucleotide binding)
Biological Process (BP): GO:0008150 (biological process), GO:0008152 (metabolic process), GO:0009987 (cellular process), GO:0044237 (cellular metabolic process), GO:0071704 (organic substance metabolic process), GO:0044238 (primary metabolic process), GO:0006807 (nitrogen compound metabolic process), GO:0006725 (cellular aromatic compound metabolic process), GO:1901360 (organic cyclic compound metabolic process), GO:0034641 (cellular nitrogen compound metabolic process), GO:0006139 (nucleobase-containing compound metabolic process), GO:0043170 (macromolecule metabolic process), GO:0046483 (heterocycle metabolic process), GO:0090304 (nucleic acid metabolic process), GO:0010467 (gene expression), GO:0016070 (RNA metabolic process), GO:0006396 (RNA processing), GO:0008380 (RNA splicing), GO:0034470 (ncRNA processing), GO:0034660 (ncRNA metabolic process), GO:0006399 (tRNA metabolic process), GO:0008033 (tRNA processing)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0005737 (cytoplasm), GO:0005622 (intracellular anatomical structure)