24719-82-2Relevant articles and documents
Efficient access to 3′-: O -phosphoramidite derivatives of tRNA related N 6-threonylcarbamoyladenosine (t6A) and 2-methylthio- N 6-threonylcarbamoyladenosine (ms2t6A)
Debiec, Katarzyna,Sochacka, Elzbieta
, p. 1992 - 1999 (2021)
An efficient method of ureido linkage formation during epimerization-free one-pot synthesis of protected hypermodified N6-threonylcarbamoyladenosine (t6A) and its 2-SMe analog (ms2t6A) was developed. The method is based on a Tf2O-mediated direct conversion of the N-Boc-protecting group of N-Boc-threonine into the isocyanate derivative, followed by reaction with the N6exo-amine function of the sugar protected nucleoside (yield 86-94%). Starting from 2′,3′,5′-tri-O-acetyl protected adenosine or 2-methylthioadenosine, the corresponding 3′-O-phosphoramidite monomers were obtained in 48% and 42% overall yield (5 step synthesis). In an analogous synthesis, using the 2′-O-(tert-butyldimethylsilyl)-3′,5′-O-(di-tert-butylsilylene) protection system at the adenosine ribose moiety, the t6A-phosphoramidite monomer was obtained in a less laborious manner and in a remarkably better yield of 74%.
A hydantoin isoform of cyclic N6-threonylcarbamoyladenosine (ct6A) is present in tRNAs
Matuszewski, Michal,Wojciechowski, Jakub,Miyauchi, Kenjyo,Gdaniec, Zofia,Wolf, Wojciech M.,Suzuki, Tsutomu,Sochacka, Elzbieta
, p. 2137 - 2149 (2017)
N6-Threonylcarbamoyladenosine (t6A) and its derivatives are universally conserved modified nucleosides found at position 37, 3 adjacent to the anticodon in tRNAs responsible for ANN codons. These modifications have pleiotropic functions of tRNAs in decoding and protein synthesis. In certain species of bacteria, fungi, plants and protists, t6A is further modified to the cyclic t6A (ct6A) via dehydration catalyzed by TcdA. This additional modification is involved in efficient decoding of tRNALys. Previous work indicated that the chemical structure of ct6A is a cyclic active ester with an oxazolone ring. In this study, we solved the crystal structure of chemically synthesized ct6A nucleoside. Unexpectedly, we found that the ct6A adopted a hydantoin isoform rather than an oxazolone isoform, and further showed that the hydantoin isoform of ct6A was actually present in Escherichia coli tRNAs. In addition, we observed that hydantoin ct6A is susceptible to epimerization under mild alkaline conditions, warning us to avoid conventional deacylation of tRNAs. A hallmark structural feature of this isoform is the twisted arrangement of the hydantoin and adenine rings. Functional roles of ct6A37 in tRNAs should be reconsidered.
Noncanonical RNA Nucleosides as Molecular Fossils of an Early Earth—Generation by Prebiotic Methylations and Carbamoylations
Schneider, Christina,Becker, Sidney,Okamura, Hidenori,Crisp, Antony,Amatov, Tynchtyk,Stadlmeier, Michael,Carell, Thomas
supporting information, p. 5943 - 5946 (2018/04/30)
The RNA-world hypothesis assumes that life on Earth started with small RNA molecules that catalyzed their own formation. Vital to this hypothesis is the need for prebiotic routes towards RNA. Contemporary RNA, however, is not only constructed from the four canonical nucleobases (A, C, G, and U), it also contains many chemically modified (noncanonical) bases. A still open question is whether these noncanonical bases were formed in parallel to the canonical bases (chemical origin) or later, when life demanded higher functional diversity (biological origin). Here we show that isocyanates in combination with sodium nitrite establish methylating and carbamoylating reactivity compatible with early Earth conditions. These reactions lead to the formation of methylated and amino acid modified nucleosides that are still extant. Our data provide a plausible scenario for the chemical origin of certain noncanonical bases, which suggests that they are fossils of an early Earth.
