TRNT1 polymerizes CCA at the 3' end of pre-tRNA

Stable Identifier
Reaction [transition]
Homo sapiens
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TRNT1 (CCA-adding enzyme) polymerizes the non-templated nucleotides CCA onto the 3' end (acceptor arm) of tRNAs (Reichert et al. 2001, Lizano et al. 2007, Lizano et al. 2008). In contrast to some eubacterial tRNA genes, eukaryotic tRNA genes do not encode CCA at the 3' end. The added CCA sequence is determined by the structural properties of the TRNT1 protein itself rather than by any nucleic acid template (Augustin et al. 2003, Ernst et al. 2015, Kuhn et al. 2015, see also the structure of the bacterial enzyme in Li et al. 2002). After polymerization of a single CCA motif, conformational change of the enzyme ejects the tRNA before additional nucleotides can be polymerized (Kuhn et al. 2015). Aberrant RNA with two CCA motifs is targeted for destruction.

Literature References
PubMed ID Title Journal Year
18226598 A comparative analysis of CCA-adding enzymes from human and E. coli: differences in CCA addition and tRNA 3'-end repair

Lizano, E, Scheibe, M, Rammelt, C, Betat, H, Mörl, M

Biochimie 2008
12729736 Crystal structure of the human CCA-adding enzyme: insights into template-independent polymerization

Augustin, MA, Reichert, AS, Betat, H, Huber, R, Mörl, M, Steegborn, C

J. Mol. Biol. 2003
11727826 A eubacterial origin for the human tRNA nucleotidyltransferase?

Reichert, AS, Thurlow, DL, Mörl, M

Biol. Chem. 2001
17204286 A splice variant of the human CCA-adding enzyme with modified activity

Lizano, E, Schuster, J, Muller, M, Kelso, J, Mörl, M

J. Mol. Biol. 2007
12526808 Crystal structures of the Bacillus stearothermophilus CCA-adding enzyme and its complexes with ATP or CTP

Li, F, Xiong, Y, Wang, J, Cho, HD, Tomita, K, Weiner, AM, Steitz, TA

Cell 2002
25849199 Domain movements during CCA-addition: A new function for motif C in the catalytic core of the human tRNA nucleotidyltransferases

Ernst, FG, Rickert, C, Bluschke, A, Betat, H, Steinhoff, HJ, Mörl, M

RNA Biol 2015
25640237 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
Event Information
Go Biological Process
Catalyst Activity

5'-3' RNA polymerase activity of TRNT1 [nucleoplasm]

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