2341-22-2Relevant articles and documents
A simple and efficient synthesis of puromycin, 2,2′-anhydro- pyrimidine nucleosides, cytidines and 2′,3′-anhydroadenosine from 3′,5′-O-sulfinyl xylo-nucleosides
Takatsuki, Ken-Ichi,Ohgushi, Sumito,Kohmoto, Shigeo,Kishikawa, Keiki,Yamamoto, Makoto
, p. 719 - 734 (2007/10/03)
Synthesis of antibiotics, puromycin and 3 ′-amino-3 ′-deoxy-N 6 ,N 6 -dimethyladenosine 11 was achieved by utilizing the cyclic sulfite 6a of the xylo -3 ′,5 ′-dihydroxy group as a new protective group. The key synthetic step is the deprotection of the sulfite moiety through the intramolecular cyclization of 2-α-carbamate 7 . In a similar manner, 2,2 ′-anhydro-pyrimidine nucleosides 15 , ribo -cytidines 17 and 2 ′,3 ′-anhydroadenosine 14 were prepared in high yields from the corresponding sulfites 4 , 5 , and 6b , respectively. Copyright Taylor & Francis Group, LLC.
A new protecting group '3′,5′-O-sulfinyl' for xylo-nucleosides. A simple and efficient synthesis of 3′-amino-3′-deoxyadenosine (a puromycin intermediate), 2,2′-anhydro-pyrimidine nucleosides and 2′,3′-anhydro-adenosine
Takatsuki, Ken-Ichi,Yamamoto, Makoto,Ohgushi, Sumito,Kohmoto, Shigeo,Kishikawa, Keiki,Yamashita, Haruhiro
, p. 137 - 140 (2007/10/03)
We developed a new protecting group, the cyclic sulfite for the protection of the 3′,5′-dihydroxy group of nucleosides. Seven cyclic sulfites, 4a-c, 5a-b, and 6a-b were prepared in high yields from the corresponding xylo-uridines 1 and 2, and xylo-adenosines 3 with thionyl chloride, respectively. Synthesis of the puromycin intermediate 8 was carried out by deprotection of the sulfite moiety through an intramolecular cyclization of the 2′-α-carbamate 7.
Biochemical detection of cytidine protonation within RNA
Oyelere,Strobel
, p. 10259 - 10267 (2007/10/03)
Perturbation of active site functional group pK(a)s is an important strategy employed by protein enzymes to achieve catalysis. There is increasing evidence to indicate that RNAs also utilize functional group pK(a) perturbation for folding and reactivity. One of the best candidates for a functionally relevant pK(a) perturbation is the N3 of C (pK(a) 4.2), which could be sufficiently raised to allow protonation near physiological pH. Here we report the synthesis and use of a series of α-phosphorothioate tagged cytidine analogues whose altered N3 pK(a)s make it possible to efficiently detect functionally relevant protonation events by nucleotide analogue interference mapping. 6-Azacytidine (n6CαS) and 5-fluorocytidine (f5CαS) both have enhanced acidity at the N3 position (pK(a) 2.6 and 2.3, respectively) but leave the hydrogen bonding face of C otherwise unaffected. In contrast, pseudoisocytidine (ΨiCαS) is a charge neutral analogue that mimics the hydrogen bonding character of protonated C. To test the utility of these analogues, we characterized the C300+-G97-C277 mutant form of the Tetrahymena group I intron, which is predicted to require C300 protonation for ribozyme folding and reactivity. At neutral to alkaline pHs, C300 was the only site of n6CαS and f5Cαs interference within the intron, yet both interferences were rescued at acidic pH. Furthermore, ΨiCαS substitution at C300 resulted in enhanced activity at alkaline pHs, consistent with the presence of an N3 proton under the pH conditions studied. Interference mapping with these analogues provides an efficient and sensitive means to identify every site within an RNA where cytidine protonation is important for RNA function and may make it possible to identify C's that participate in general acid/base catalysis within ribozyme active sites.
