Reaction: selenophosphate + geranyl diphosphate + 5-methylaminomethyl-2-thiouridine34 in tRNA + H2O = 5-methylaminomethyl-2-selenouridine34 in tRNA + (2E)-3,7-dimethylocta-2,6-diene-1-thiol + diphosphate + phosphate (overall reaction)
(1a) geranyl diphosphate + 5-methylaminomethyl-2-thiouridine34 in tRNA = 5-methylaminomethyl-2-(S-geranyl)thiouridine34 in tRNA + diphosphate
(1b) selenophosphate + 5-methylaminomethyl-2-(S-geranyl)thiouridine34 in tRNA = 5-methylaminomethyl-2-(Se-phospho)selenouridine34 in tRNA + (2E)-3,7-dimethylocta-2,6-diene-1-thiol
(1c) 5-methylaminomethyl-2-(Se-phospho)selenouridine34 in tRNA + H2O = 5-methylaminomethyl-2-selenouridine34 in tRNA + phosphate
Other name(s): selU (gene name); mnmH (gene name); ybbB (gene name); sufY (gene name)
Systematic name: geranyl diphosphate/selenophosphate:tRNA 5-methylaminomethyl-2-thiouridine34 geranyl/selenophosphatetransferase
Comments: This bacterial enzyme converts 5-methylaminomethyl-2-uridine and 5-carboxymethylaminomethyl-2-uridine to the respective selenouridine forms in a two-step process that involves geranylation and subsequent phosphoselenation of the resulting geranylated intermediates. The resultant seleno-phosphorylated uridine intermediates further react with a water molecule to release a phosphate anion and 2-selenouridine tRNA. The enzyme contains a rhodanese domain.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Bartos, P., Maciaszek, A., Rosinska, A., Sochacka, E. and Nawrot, B. Transformation of a wobble 2-thiouridine to 2-selenouridine via S-geranyl-2-thiouridine as a possible cellular pathway. Bioorg. Chem. 56 (2014) 49-53. [PMID: 24971911]
2. Jager, G., Chen, P. and Bjork, G.R. Transfer RNA bound to mnmh protein is enriched with geranylated tRNA—a possible intermediate in its selenation. PLoS One 11 (2016) e0153488. [PMID: 27073879]
3. Sierant, M., Leszczynska, G., Sadowska, K., Komar, P., Radzikowska-Cieciura, E., Sochacka, E. and Nawrot, B. Escherichia coli tRNA 2-selenouridine synthase (SelU) converts S2U-RNA to Se2U-RNA via S-geranylated-intermediate. FEBS Lett. 592 (2018) 2248-2258. [PMID: 29862510]