Effect of triphosphate modifications in 2′-deoxynucleoside 5′-triphosphates on their specificity towards various DNA polymerases

Abstract

Some natural and glycon-modified dNTPs with β,γ-pyrophosphate substitution at the triphosphate residue were synthesized and studied to evaluate the effect of these modifications on substrate properties of dNTPs in DNA synthesis catalyzed by human placental DNA polymerases α and β, avian myeloblastosis virus reverse transcriptase, and calf thymus terminal deoxynucleotidyl transferase. Reverse transcriptase proved to be the enzyme least specific to such modifications; the substrate activity of β,γ-methylenediphosphonate substituted dTTP and 3′-azido-3′-deoxy-dTTP decreased in the following order: CF 2=CHF>CBr 2>CFMe≫CH 2. This order is individual for each DNA polymerase. It is interesting to mention that β,γ-CBr 2 substituted dTTP is neither a substrate nor an inhibitor of DNA polymerase β. This specificity distinguishes DNA polymerase β from other DNA polymerases studied.