Antisense oligonuclotides with oxetane-constrained cytidine enhance heteroduplex stability, and elicit satisfactory RNase H response as well as showing improved resistance to both exo and endonucleases†
Abstract
Antisense modifications [1′,2′-oxetane constrained
-modified AONs, for their antisense potentials by targeting to a 15mer complementary RNA. Although the
modified mixmer AONs show ∼3 °C drop per modification in melting temperature (Tm) of their hybrid AON–RNA duplexes, they are found to be good substrates for RNase H, in comparison with the native AON–RNA duplex. An AON with double
modifications along with 3′-DPPZ (
modified AON–RNA duplexes as well as double
modifications along with 3′-DPPZ have catalytic activities (kcat) close to the native. However, the RNase H binding affinity (1/Km) showed a slight decrease with increase in the number of modifications, which results in less effective enzyme activity (kcat/Km) for
modified AON–RNA duplexes. All
modified AONs (with 3′-DPPZ), as in the
counterpart, showed an enhanced tolerance towards the endonuclease and exonuclease degradation compared to the native (the