Reactions of 2-thioribothymidine and 4-thiouridine with hydrogen peroxide in transfer ribonucleic acids from Thermus thermophilus and Escherichia coli as studied by circular dichroism

Watanabe, Kimitsuna

doi:10.1021/bi00565a013

Cited by 25 publications

(22 citation statements)

References 31 publications

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“…CD and UV measurements. CD spectra were obtained with a JASCO (Japan Spectroscopic Co. Ltd) J-500A spectropolarimeter as already reported [19,20]. The temperature was set at 20°C unless otherwise indicated.…”

Section: Methodsmentioning

confidence: 99%

“…In a comparative study of the tertiary structures of glutamic acid tRNA (tRNAGlu) and lysine tRNA (tRNALYs) isolated from E.coli, both of which have very similar anticodon loop sequences, with the same hypermodified nucleoside 5-methylaminomethyl-2-thiouridine (mnm5s2U) at position 34 [2], we found that the anticodon structure of tRNALYS is actually different from that of tRNAGlu [16] in terms of circular dichroism (CD), which is known to be a very sensitive method for detecting the conformation of sulfur-containing nucleosides (or nucleotides) such as 4-thiouridine [17], 5-methyl-2-thiouridine [18,19] and mnm5s2U [19,20]. Since tRNAGlu is known to have a normal anticodon loop structure with respect to CD [19][20][21][22], as well as sensitivity towards nucleases [23,24], the anticodon of tRNALYS appears to be different in its tertiary structure from those of most tRNAs so far studied [3][4][5][6][7][8][9][10][11][12].…”

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confidence: 99%

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Unusual anticodon loop structure found inE.colilysine tRNA

Watanabe¹,

Hayashi

Oyama³

et al. 1994

Nucl Acids Res

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Although both tRNA(Lys) and tRNA(Glu) of E. coli possess similar anticodon loop sequences, with the same hypermodified nucleoside 5-methylaminomethyl-2-thiouridine (mnm5s2U) at the first position of their anticodons, the anticodon loop structures of these two tRNAs containing the modified nucleoside appear to be quite different as judged from the following observations. (1) The CD band derived from the mnm5s2U residue is negative for tRNA(Glu), but positive for tRNA(Lys). (2) The mnm5s2U monomer itself and the mnm5s2U-containing anticodon loop fragment of tRNA(Lys) show the same negative CD bands as that of tRNA(Glu). (3) The positive CD band of tRNA(Lys) changes to negative when the temperature is raised. (4) The reactivity of the mnm5s2U residue toward H2O2 is much lower for tRNA(Lys) than for tRNA(Glu). These features suggest that tRNA(Lys) has an unusual anticodon loop structure, in which the mnm5s2U residue takes a different conformation from that of tRNA(Glu); whereas the mnm5s2U base of tRNA(Glu) has no direct bonding with other bases and is accessible to a solvent, that of tRNA(Lys) exists as if in some way buried in its anticodon loop. The limited hydrolysis of both tRNAs by various RNases suggests that some differences exist in the higher order structures of tRNA(Lys) and tRNA(Glu). The influence of the unusual anticodon loop structure observed for tRNA(Lys) on its function in the translational process is also discussed.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Unusual anticodon loop structure found inE.colilysine tRNA

Watanabe¹,

Hayashi

Oyama³

et al. 1994

Nucl Acids Res

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“…The CNBr-oxidized tRNA species specific for Glu, Gln and Lys lost their potential to be aminoacylated by their cognate aa-RSs. It has been shown (either at the nucleoside or entire tRNA level) that the 2-thiouridines are oxidized by H 2 O 2 to uridine and to another “H 2 O 2 -altered”, unidentified product, but not to a ring-opened or disulfide structure [60]. Dethiolation of E. coli tRNA Glu in oxidative conditions led to more than 95% conversion of the 2-thiouridine 34 to uridine, as assigned by base composition analysis [61].…”

Section: Oxidative Dethiolation Of Trnasmentioning

confidence: 99%

tRNA structural and functional changes induced by oxidative stress

Nawrot

Sochacka

Duechler

2011

Cell. Mol. Life Sci.

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Oxidatively damaged biomolecules impair cellular functions and contribute to the pathology of a variety of diseases. RNA is also attacked by reactive oxygen species, and oxidized RNA is increasingly recognized as an important contributor to neurodegenerative complications in humans. Recently, evidence has accumulated supporting the notion that tRNA is involved in cellular responses to various stress conditions. This review focuses on the intriguing consequences of oxidative modification of tRNA at the structural and functional level.

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“…Hyperreactivity is not observed x.~hen probing dethiolated tRNA Lye3, the modified uridine of "~hich has been identified as mcm~U [6] indicating that the ~ulfur atom of the base is crucial for the enhanced cleavage ~:lata not shown). The ONOOK-induced strand scission at ,',34 is reminiscent of the dethiolation reaction itself, which performed in the presence of hydrogen peroxide [6,7]. We ,uggest that both reactions, namely the particular cleavage ,dth ONOOK and conversion of thiouridine into uridine with hydrogenperoxide, may initially require nucleophilic atack of a peroxo-species at the thiocarbonyl group of $34.…”

Section: Resultsmentioning

confidence: 99%

Probing the higher order structure of RNA with peroxonitrous acid

et al. 1996

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Potassium peroxonitrite (ONOOK) and [Fe(ED-TAis known to induce oxidative strand seission at sugar moieties thought to be solvent accessible, while those residues located in the 'inside' of structured RNAs are protected. Although ONOOH is neutral and significantly smaller than the metal complex, both reagents generate the same protection pattern on tRNAs, suggesting that access of the commonly formed hydroxyl radical, rather than access of its source, is the determining factor when probing the higher order structure of RNA. Strong difference in reactivity is only seen at the modified 2-thiouridine $34 of tRNA Lys3 which shows hyperreactivity towards ONOOK treatment. This particular reaction may require interaction between the peroxonitrite anion and the thiocarbonyl group of the base, since hyperreactivity is not observed when probing the dethiolated tRNA Lye3.

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Reactions of 2-thioribothymidine and 4-thiouridine with hydrogen peroxide in transfer ribonucleic acids from Thermus thermophilus and Escherichia coli as studied by circular dichroism

Cited by 25 publications

References 31 publications

Unusual anticodon loop structure found inE.colilysine tRNA

Unusual anticodon loop structure found inE.colilysine tRNA

tRNA structural and functional changes induced by oxidative stress

Probing the higher order structure of RNA with peroxonitrous acid

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