Synthesis and Thermal Denaturation Studies of Conformationally Restricted 3′‐C‐Ethynyl‐3′‐O,4′‐C‐methyleneribonucleotides

Abstract

Incorporation of conformationally restricted 3′‐C‐ethynyl‐3′‐O,4′‐C‐methyleneribonucleotide X monomers into oligodeoxyribonucleotides results in large decreases in affinity towards complementary DNA, whereas significantly more stable duplexes are formed with RNA complements. RNA selectivity becomes more pronounced upon multiple incorporations of X monomers. Increased thermal stability is observed upon positioning of two X monomers in a +1 zipper interstrand motif. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Synthesis and Properties of Oligonucleotides Containing 3′-O,4′-C-Ethyleneoxy-Bridged 5-Methyluridines

“…The duplex formation ability of oligonucleotides containing other 3ʹ,4ʹ-bridged nucleosides 1-3 ( Figure 1) with ssDNA and ssRNA was previously reported. 13,14 The stability appeared to be highly dependent on the sequence and the modification pattern. 3ʹ,4ʹ-BNA-T 1 and 3ʹ,4ʹ-BNA-U 2 showed ΔTm/mod.…”

“…9,10 Several reports have been published regarding 3′,5′-linked oligonucleotides containing 2′,5′-phosphodiester linkages. [12][13][14][15] For example, the incorporation of 3′,4′-bridged nucleic acid analogs 1-3 forming 2′,5′-linkages ( Figure 1) into natural 3′,5′-linked oligonucleotides led to moderate or large decreases in the affinities towards ssDNA as compared to unmodified DNA, whereas the affinity towards ssRNA did not change appreciably. 13,14 Accordingly, oligonucleotides containing 3′,4′-bridged nucleic acid analogs 1-3 could form duplexes with ssRNA in an RNA-selective manner.…”