THYMIDINE, 2-THIOTHYMIDINE, AND 2-SELENOTHYMIDINE: COMPARISON OF MISMATCH DISCRIMINATIONS

摘要

Oligonucleotides modified using 2-thiothymidine ((ST)-T-2) or 2-selenothymidine ((SeT)-T-2), which are thymidine analogs bearing either sulfur or selenium atoms, respectively, have been independently shown to suppress the formation of mismatched wobble base pairs with guanine when forming a duplex with single stranded DNA. However, limited data comparing the base discriminations of (ST)-T-2- and (SeT)-T-2-modified oligonucleotides, especially toward single stranded RNA, are available. Here, we report a comprehensive data set of the base discriminations of (ST)-T-2- and (SeT)-T-2-modified oligonucleotides toward both single stranded DNA and RNA. Our results demonstrate that (ST)-T-2- and (SeT)-T-2-modified oligonucleotides have similar base discrimination abilities. An important feature observed in both the (ST)-T-2- and (SeT)-T-2-modified oligonucleotides is their extremely high base discrimination toward single stranded RNA. Thus, (ST)-T-2 and (SeT)-T-2 modifications may be useful for therapeutic oligonucleotides targeting single stranded RNAs.