Structural highlights
4x4w is a 2 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
|
| Ligands: | , , , |
| Gene: | TRNT1, CGI-47 (HUMAN) |
| Activity: | CCA tRNA nucleotidyltransferase, with EC number 2.7.7.72 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[TRNT1_HUMAN] Isoform 1: Adds and repairs the conserved 3'-CCA sequence necessary for the attachment of amino acids to the 3' terminus of tRNA molecules, using CTP and ATP as substrates.[1] Isoform 2: Adds 2 C residues (CC-) to the 3' terminus of tRNA molecules instead of a complete CCA end as isoform 1 does (in vitro).[2]
Publication Abstract from PubMed
Transcription in eukaryotes produces a number of long noncoding RNAs (lncRNAs). Two of these, MALAT1 and Menbeta, generate a tRNA-like small RNA in addition to the mature lncRNA. The stability of these tRNA-like small RNAs and bona fide tRNAs is monitored by the CCA-adding enzyme. Whereas CCA is added to stable tRNAs and tRNA-like transcripts, a second CCA repeat is added to certain unstable transcripts to initiate their degradation. Here, we characterize how these two scenarios are distinguished. 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. Intriguingly, with the CCA-adding enzyme acting as a molecular vise, the RNAs proofread themselves through differential responses to its interrogation between stable and unstable substrates.
On-Enzyme Refolding Permits Small RNA and tRNA Surveillance by the CCA-Adding Enzyme.,Kuhn CD, Wilusz JE, Zheng Y, Beal PA, Joshua-Tor L Cell. 2015 Feb 12;160(4):644-58. doi: 10.1016/j.cell.2015.01.005. Epub 2015 Jan, 29. PMID:25640237[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Lizano E, Schuster J, Muller M, Kelso J, Morl M. A splice variant of the human CCA-adding enzyme with modified activity. J Mol Biol. 2007 Mar 2;366(4):1258-65. Epub 2006 Dec 12. PMID:17204286 doi:http://dx.doi.org/10.1016/j.jmb.2006.12.016
- ↑ Lizano E, Schuster J, Muller M, Kelso J, Morl M. A splice variant of the human CCA-adding enzyme with modified activity. J Mol Biol. 2007 Mar 2;366(4):1258-65. Epub 2006 Dec 12. PMID:17204286 doi:http://dx.doi.org/10.1016/j.jmb.2006.12.016
- ↑ Kuhn CD, Wilusz JE, Zheng Y, Beal PA, Joshua-Tor L. On-Enzyme Refolding Permits Small RNA and tRNA Surveillance by the CCA-Adding Enzyme. Cell. 2015 Feb 12;160(4):644-58. doi: 10.1016/j.cell.2015.01.005. Epub 2015 Jan, 29. PMID:25640237 doi:http://dx.doi.org/10.1016/j.cell.2015.01.005
