Remarkable acceleration of a DNA/RNA inter-strand functionality transfer reaction to modify a cytosine residue: the proximity effect via complexation with a metal cation.
Bottom Line: We have recently developed a new strategy for the in situ modification of RNA based on the functionality transfer reaction between an oligodeoxynucleotide probe and an RNA substrate. 2'-Deoxy-6-thioguanosine (6-thio-dG) was used as the platform to anchor the transfer group.It was demonstrated that the (E)-pyridinyl vinyl keto group was efficiently and specifically transferred to the 4-amino group of the opposing cytosine in RNA in the presence of NiCl2 with more than 200-fold accelerated rate compared with the previous system with the use of the diketo transfer group.Detailed mechanistic studies suggested that NiCl2 forms a bridging complex between the pyridinyl keto moiety and the N7 of the purine residue neighboring the cytosine residue of the RNA substrate to bring the groups in close proximity.
Affiliation: Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 Japan, and CREST, Japan Science and Technology Agency, 4-1-8 Motomachi, Kawaguchi, Saitama 332-0012, Japan.Show MeSH
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Mentions: Effect of metal cations on the transfer yield. (A) Comparison of the yields in the presence of 5 μM of MCl2. (B) Effect of the concentration of NiCl2. The transfer yields at 1 h are compared. The reaction conditions are the same as described in the footnote to Figure 3 except that the yield was measured after 60 min.
Affiliation: Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 Japan, and CREST, Japan Science and Technology Agency, 4-1-8 Motomachi, Kawaguchi, Saitama 332-0012, Japan.