Thionucleosides in transfer ribonucleic acid: diversity, structure, biosynthesis, and function

Ajitkumar, Parthasarathi; Cherayil, Joseph D.

doi:10.1128/mr.52.1.103-113.1988

Cited by 46 publications

(16 citation statements)

References 105 publications

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“…Thiopyrimidines and methylthiopurines are normal constituents of tRNA in all organisms and are thought to have important regulatory functions in translation [95]. The introduction of sulphur is a posttranscriptional modification of tRNA.…”

Section: Sulphuration Of Trnamentioning

confidence: 99%

Sulphane sulphur in biological systems: a possible regulatory role

Toohey¹

1989

Biochemical Journal

227

186

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cess appears to be essential for making the sulphur cyanolysable as evidenced by the acquisition of cyanolysability when ,-mercaptopyruvate is converted to the disulphide; only the latter can give the -S(S)form. This tautomerization can also occur in polysulphides and the lability of the sulphur in polysulphides with n > 3 compared with the stability of dialkyldisulphides (n = 2) again reflects the capacity to tautomerize

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Section: Sulphuration Of Trnamentioning

confidence: 99%

Sulphane sulphur in biological systems: a possible regulatory role

Toohey¹

1989

Biochemical Journal

227

186

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“…Sulfur 1 and selenium 2 substituted nucleobases (thymine, cytosine and uracil) are present in tRNA. These substitutions affect a variety of functions such as base-pairing selectivity, translation of proteins, and oxygen tolerance in anaerobic microorganisms.…”

Section: Introductionmentioning

confidence: 99%

Interplay between Conjugation and Size-Driven Delocalization Leads to Characteristic Properties of Substituted Thymines

Manae

Hazra

2017

J. Phys. Chem. A

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Substituted thymines, where oxygen is replaced by sulfur or selenium, affect a variety of functions in biological systems and are prospective phototherapeutic agents. In this study, we show that an interplay between two types of delocalization, one due to conjugation and the other owing to the varying size of the substituted atom, leads to distinct absorption spectra and electrophilic sites in substituted thymines. This result is supported by ab initio quantum chemical calculations and a simple particle-in-a-box model. The model explains the unexpected variation in the absorption of 2-thiothymine and 4-thiothymine and makes an unanticipated prediction about the nature of the LUMO in 2-selenothymine that is confirmed by quantum chemical calculations. Here, delocalization due to the large size of selenium dominates that due to conjugation; in essence, a 2-center delocalization exerts a greater influence on molecular properties than a 4-center delocalization. The study highlights that the widely used concept of delocalization may be affected not only by the long-established idea of double bond conjugation but also delocalization owing to the size of atoms.

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“…It is involved, for instance, in regulatory processes in the cell and in tRNA thiolation, has antioxidant properties and affects the functioning of the immune system. [5][6][7] In addition to many life processes that require the presence of this form of sulfur, there are hypotheses that it is also important in neoplastic cell proliferation. 6,[8][9][10] Sulfane sulfur production was observed by Wr obel et al in brain glioma tissues of various grades of malignancy.…”

Section: Introductionmentioning

confidence: 99%