Hybridization and Mismatch Discrimination Abilities of 2′,4′-Bridged Nucleic Acids Bearing 2-Thiothymine or 2-Selenothymine Nucleobase
作者:Takaki Habuchi、Takao Yamaguchi、Hiroshi Aoyama、Masahiko Horiba、Kosuke Ramon Ito、Satoshi Obika
DOI:10.1021/acs.joc.8b02863
日期:2019.2.1
Oligonucleotides modified with 2'-O,4'-C-spirocyclopropylene-bridged nucleic acid (scpBNA) exhibit excellent duplex-forming ability with their complementary single-stranded RNA (ssRNA). Here, we demonstrate that scpBNA bearing a 2-thiothymine (scpBNA-(ST)-T-2) or 2-selenothymine (scpBNA-(SeT)-T-2) nucleobase provides robust mismatch discrimination capabilities to oligonucleotides without compromising their high binding affinities toward the full complementary ssRNA. X-ray crystallographic analysis of a self-assembling oligonucleotide featuring 2',4'-BNA/LNA-2-thiothymine (2',4'-BNA/LNA-(ST)-T-2, where 2',4'-BNA and LNA stand for "2'-O,4'-C-methylene-bridged nucleic acid" and "locked nucleic acid", respectively), a prototype of scpBNA-(ST)-T-2, revealed that the 2-thiocarbonyl moiety plays a crucial role in the destabilization of thymine-guanine mismatched wobble base pairs.