IUBMB Enzyme Nomenclature


Accepted name: 2'-phosphotransferase

Reaction: 2'-phospho-[ligated tRNA] + NAD+ = mature tRNA + ADP-ribose 1",2"-phosphate + nicotinamide

For diagram click here and for mechanism, 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, PDB, 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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