Synthesis and Properties of Adenosine Oligonucleotide Analogues Containing Methylene Groups in Place of Phosphodiester 5′-Oxygens

Abstract

The ADP analogue in which the 5′-oxygen has been replaced by a methylene group can be prepared by condensing 5′-deoxy-5′-phosphonomethyladenosine with inorganic phosphate. This analogue readily polymerizes onto the primer A-A in the presence of the enzyme polynucleotide Phosphorylase and either Mg2+ or Mn2+. The initial products are of the form A-A(-cA)n-cA (where “-” and “-c” stand for the normal phosphodiester linkage and the linkage in which the 5′-oxygen is replaced with the methylene group, respectively). Treatment of these with alkali yields adenosine 2′(3′)-phosphate and the series (A(-cA).,-cA containing only phosphonomethylene linkages. The decamer A(-cA)8-cA interacts with two molecules of U(-U)8-U to form a triple-standard structure that has a stability similar to that exhibited by the analogous complex formed from A(-A)8-A and U(-U)8-U. This property, along with the resistance of these oligomer analogues toward nucleases that cleave phosphodiester linkages between the phosphorus and the 5′-oxygen, should provide a strong rationale for application of phosphonomethylene linkages in schemes for therapeutic drug design that use the antisense strategy. © 1993, American Chemical Society. All rights reserved.