Expansion of triplex recognition codes by the use of novel bicyclic nucleoside derivatives (WNA)

Recently, we have developed new base analogs (WNA) and demonstrated that WNA-&#6T538;T with thymine and WNA-C with cytosine stabilize non-natural antiparallel triplexes with a TA or a CG interrupting site, respectively. However, limitations in recognizable sequences with the WNA-containing TFO were also found. The objective of this study is to search better WNA analogs for expansion of triplex recognition codes to general duplex sequences. In this study, we designed new WNA analogs by systematic modification of the aromatic part and the recognition part. The new WNA analogs with the benzene ring substituted with bromide or cyanide have determined for selective stabilization of triplexes at a TA interrupting site, and general formation of triplexes having a TA interrupting site has been achieved.