title: Role of ribothymidine in the thermal stability of transfer RNA as monitored by proton magnetic resonance.
abstract: In order to elucidate the functional role of the modified uridines at position 54 of tRNA, the 270 MHz high-field proton NMR spectra of methionine tRNAs from E. coli, from a mutant thereof, and from T. thermophilus, containing ribothymidine, uridine and 2-thioribothymidine, respectively, have been measured as a function of temperature. A comparison of the NMR melting profiles of the minor nucleosides from these tRNAs shows that the melting temperature of uridine containing tRNA is 6 degrees C lower than that of the wild type tRNA whereas that of the 2-thioribothymidine tRNA is 7 degrees C higher than that of the wild type tRNA. These results, therefore, demonstrate that these modifications serve for stabilization of the tertiary structure of tRNA.
mesh_terms: D004355:Drug Stability; D004926:Escherichia coli / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D009239:N-Formylmethionine; D009690:Nucleic Acid Conformation; D012343:RNA, Transfer; D013045:Species Specificity; D013824:Thermus / Q000032:analysis; D014529:Uridine / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: C009182:ribothymidine; D009239:N-Formylmethionine; D012343:RNA, Transfer; D014529:Uridine