The Enzyme Database

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Accepted name: 2′-phosphotransferase
Reaction: 2′-phospho-[ligated tRNA] + NAD+ = mature tRNA + ADP-ribose 1′′,2′′-phosphate + nicotinamide
For diagram of tRNA splicing, click here
Glossary: ADP-ribose = adenosine 5′-(5-deoxy-D-ribofuranos-5-yl diphosphate)
Other name(s): yeast 2′-phosphotransferase; Tpt1; Tpt1p; 2′-phospho-tRNA:NAD+ phosphotransferase
Systematic name: 2′-phospho-[ligated tRNA]:NAD+ phosphotransferase
Comments: Catalyses the final step of tRNA splicing in the yeast Saccharomyces cerevisiae [2]. The reaction takes place in two steps: in the first step, the 2′-phosphate on the RNA substrate is ADP-ribosylated, causing the relase of nicotinamide and the formation of the reaction intermediate, ADP-ribosylated tRNA [6]. In the second step, dephosphorylated (mature) tRNA is formed along with ADP ribose 1′′-2′′-cyclic phosphate. Highly specific for oligonucleotide substrates bearing an internal 2′-phosphate. Oligonucleotides with only a terminal 5′- or 3′-phosphate are not substrates [1].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 126905-00-8
1.  Steiger, M.A., Kierzek, R., Turner, D.H. and Phizicky, E.M. Substrate recognition by a yeast 2′-phosphotransferase involved in tRNA splicing and by its Escherichia coli homolog. Biochemistry 40 (2001) 14098–14105. [PMID: 11705403]
2.  Spinelli, S.L., Kierzek, R., Turner, D.H. and Phizicky, E.M. Transient ADP-ribosylation of a 2′-phosphate implicated in its removal from ligated tRNA during splicing in yeast. J. Biol. Chem. 274 (1999) 2637–2644. [PMID: 9915792]
3.  Culver, G.M., McCraith, S.M., Consaul, S.A., Stanford, D.R. and Phizicky, E.M. A 2′-phosphotransferase implicated in tRNA splicing is essential in Saccharomyces cerevisiae. J. Biol. Chem. 272 (1997) 13203–13210. [PMID: 9148937]
4.  McCraith, S.M. and Phizicky, E.M. An enzyme from Saccharomyces cerevisiae uses NAD+ to transfer the splice junction 2′-phosphate from ligated tRNA to an acceptor molecule. J. Biol. Chem. 266 (1991) 11986–11992. [PMID: 2050693]
5.  Hu, Q.D., Lu, H., Huo, K., Ying, K., Li, J., Xie, Y., Mao, Y. and Li, Y.Y. A human homolog of the yeast gene encoding tRNA 2′-phosphotransferase: cloning, characterization and complementation analysis. Cell. Mol. Life Sci. 60 (2003) 1725–1732. [PMID: 14504659]
6.  Steiger, M.A., Jackman, J.E. and Phizicky, E.M. Analysis of 2′-phosphotransferase (Tpt1p) from Saccharomyces cerevisiae: evidence for a conserved two-step reaction mechanism. RNA 11 (2005) 99–106. [PMID: 15611300]
7.  Sawaya, R., Schwer, B. and Shuman, S. Structure-function analysis of the yeast NAD+-dependent tRNA 2′-phosphotransferase Tpt1. RNA 11 (2005) 107–113. [PMID: 15611301]
8.  Kato-Murayama, M., Bessho, Y., Shirouzu, M. and Yokoyama, S. Crystal structure of the RNA 2′-phosphotransferase from Aeropyrum pernix K1. J. Mol. Biol. 348 (2005) 295–305. [PMID: 15811369]
[EC created 2006]

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