"S-Geranyl-2-thiouridine wobble nucleosides of bacterial tRNAs; chemical and enzymatic synthesis of S-geranylated-RNAs and their physicochemical characterization"

Malgorzata Sierant,, Grazyna Leszczynska,, Klaudia Sadowska, Agnieszka Dziergowska, Michal Rozanski, Elzbieta Sochacka, and Barbara Nawrot



Published 2016-08-26 in Nucleic Acids Res. volume 2016 Dec 15; 44(22): 10986–109 .

Pubmed ID: 5159532
DOI identifier: 10.1093/nar/gkw727

Abstract:
Recently, highly lipophilic S-geranylated derivatives of 5-methylaminomethyl-2-thiouridine (mnm5geS2U) and 5-carboxymethylaminomethyl-2-thiouridine (cmnm5geS2U) were found at the first (wobble) anticodon position in bacterial tRNAs specific for Lys, Glu and Gln. The function and cellular biogenesis of these unique tRNAs remain poorly understood. Here, we present one direct and two post-synthetic chemical routes for preparing model geS2U-RNAs. Our experimental data demonstrate that geS2U-RNAs are more lipophilic than their parent S2U-RNAs as well as non-modified U-RNAs. Thermodynamic studies revealed that the S-geranyl-2-thiouridine-containing RNA has higher affinity toward complementary RNA strand with G opposite the modified unit than with A. Recombinant tRNA selenouridine synthase (SelU) exhibits sulfur-specific geranylation activity toward model S2U-RNA, which is composed of the anticodon-stem-loop (ASL) from the human tRNALys3 sequence. In addition, the presence of magnesium ions is required to achieve appreciable geranylation efficiencies.


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