| Co-Investigator(Kenkyū-buntansha) |
HIRAOKA Shuich The University of Tokyo, Graduate School of Science, Research Associate, 大学院・理学系研究科, 助手 (10322538)
TANAKA Kentaro The University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (40281589)
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| Research Abstract |
The strategy of replacing DNA natural bases by alternative ones has allowed the modification of DNA in a highly specific and site-selective manner, because DNA has a structural basis to array predesigned building blocks. We have recently envisioned the replacement of hydrogen-bonded base pairing present in natural DNA by metalmediated base pairing. Incorporation of such metal-induced base pairs into DNA would not only affect the assembly-disassembly processes and the structure of DNA double strands but also confer a variety of metal-based functions upon DNA. The chemistry thus interfaces with both life sciences and materials science
Along this line, we designed and synthesized metal-mediated base pairs with nucleosides bearing a phenylenediamine, a catechol, a 2-aminophenol, a pyridine, or a hydroxypyridone as the nucleobase. Some of them were successfully incorporated into DNA and were found to stabilize the duplex or triplex structures. Recently, we reported the synthesis of a series of artificial oligonucleotides, d(5 -GH_nC-3 ) (n = 1-5), using hydroxypyridone nucleobases (H) as flat bidentate ligands. Right-handed double helices of the oligonucleotides, nCu^<2+> d(5 -GH_nC-3 )_2 (n = 1-5), were quantitatively formed through Cu^<2+>-mediated alternative base pairing (H-Cu^<2+>-H), where the Cu^<2+> incorporated into each complex were aligned along the helix axes inside the duplexes with the Cu^<2+>-Cu^<2+> of 3.7 -0.1 angstrom. The Cu^<2+> ions were coupled ferromagnetically with one another through unpaired d electrons to form magnetic chains.
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