DINUCLEOSIDE PHOSPHATES CONTAINING ARABINOSE OR DEOXYXYLOSE - HYDROLYSIS BY EXONUCLEASES AND STACKING PROPERTIES

Two pairs of isomeric dinucleoside monophosphates containing either 1-(β-D-arabinofuranosyl)uracil (arabino-U, aU) or 1-(/3-D-2-deoxy-threo-pentofuranosyl) thymine (2'-deoxyxylo-T, dxT) were synthesized. The kinetics of the hydrolysis of these dimers by venom and spleen phosphodiesterases (PDE) were studied. In addition, circular dichroism was used to study their stacking behaviour. A correlation was found to exist between the enzymatic cleavage rate and the conformation of the dimers. It was found that the configuration change at C-2’ or C-3’ in the 5’-terminal nucleoside residue, especially the inversion of 3’-hydroxyl involved into the internucleotide 3'-5’-phos-phodiester linkage formation, was critical. © 1990, Taylor & Francis Group, LLC. All rights reserved.